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MoS 2 modification by doping transition metals is an effective way to change the Mo–S bond energy by taking advantage of the electronic variability of the d orbitals of transition metals. Herein, this study investigates the doping effect of different transition metals onto MoS 2 edge sites through DFT calculations. To screen out the metal additive effect, different transition metals were doped to the MoS 2 edge sites to see the effect on generating S vacancies that were generally regarded as the active sites. DFT simulation results proved that the ability of the valence electrons to populate the orbitals with the greatest overlap with the orientation of the edge Mo–S bond was a major factor in how simple it was to create S vacancies at the Mo-edge and S-edge sites. For the transition metals, the vacancy formation energy increases with the increase of periodic number for the same group, while decreases with the increase of the atomic weight for the same period. This implied that the upper right corner transition metals in the Periodic Table could be selected to modify MoS 2 to obtain the minimum vacancy formation energy. Therefore, nickel and cobalt are the best choice as the doping element for modifying MoS 2. [Display omitted] • The correlation between transition metal-doped MoS 2 edge sites and vacancy formation energy is unveiled. • Co and Ni doping modified MoS 2 were found to promote the generation of S-edge sites. • The correlation between electron filling in d orbitals and S vacancy formation energy is revealed. [ABSTRACT FROM AUTHOR]

Efficient hydrogen production relies on cost-effective and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER). In this work, a liquid metal-assisted solid-flame combustion synthesis (SF-CS) method was used to create transition metal carbide TMC) nanocrystals with exposed facets. The TMCs include TiC, VC, NbC, TaC, Ta 2 C, WC, and Mo 2 C. In acidic solutions, the TMC nanocrystals show enhanced conductivity and superior HER performance, as evidenced by their lower Tafel slope, higher current density, and decreased overpotential. In particular, Mo 2 C nanocrystals exhibit an overpotential of 95 mV and a Tafel slope of 26 mV dec−1. These findings highlight a noteworthy improvement over previously reported nanostructures in recent years in terms of the HER properties of Mo 2 C with particular facets. This improvement is attributed to the unique surface characteristics, such as energy and active sites, which are impacted by various factors and require more investigation to meet the intended goals. [Display omitted] [ABSTRACT FROM AUTHOR]

This investigation aimed to study the effects of adding TiO 2 on many aspects of 1393-B3 glasses, including their physio-chemical, mechanical parameters, crystallization behaviour, in-vitro bioactivity, hemocompatibility, and cellular viability. Here, we replaced 1393 glass silica with boric oxide to determine a more effective alternative. 1393-B3 bioactive glasses having the general weight % composition (53-X) B 2 O 3 , 6 Na 2 O, 5 MgO, 20 CaO, 12 K 2 O, 4 P 2 O 5 , X TiO 2 (where X = 0, 1.0, 1.5, 2.0, and 2.5 %) were prepared using solid-state melt quenching method in platinum crucible at 1100 °C for 2 h in an electric furnace with air as furnace atmosphere. This research aimed to investigate the complete substitution of 1393 glass silica with boric oxide in order to get a reduced melting temperature forming 1393-B3. The objective was to develop a more energy-efficient and economical bioactive glass. Thermal analysis of the samples was obtained up to 700 °C. To evaluate the in-vitro bioactivity, the samples were immersed in simulated body fluid (SBF). These materials undergo XRD, FTIR, and SEM/EDAX analysis both before and after soaking in SBF. These characterization results show the presence of a hydroxyapatite (HA) layer forming on the samples of the bioactive glass surface. The haemolysis process performed on human blood shows its haemocompatibility result. To test these results for the human body. We performed cell proliferation and cell compatibility on the MG-63 cell line to see its effect on osteosarcoma patients. Density (2.31–2.48 gm/cm3), pH value (7.4–8.86), and mechanical parameters such as compressive strength (98–125 MPa), flexural strength (33–54), and elasticity are measured. As a result, physio-chemical, mechanical, biological properties and in-vitro bioactivity of these samples were obtained with increasing concentration of TiO 2 in 1393-B3 borate bioactive glass and found to increase with increasing concentration of TiO 2. [ABSTRACT FROM AUTHOR]

Monolithic catalyst is very important for the further industrial application of hydrogen production via NaBH 4 hydrolysis. Nowadays, the structural stability and catalytic performance of aerogel based monolithic catalysts still need to be further improved. Herein, the amorphous Ru–Co(OH) x @GO particles are synthesized by in-situ growth and transformation of ZIF-67 on the surface of GO, the hydrogen generation rate and activation energy via catalytic NaBH 4 hydrolysis can reach 11,062 mL min−1 g−1 and 36.2 kJ mol−1, respectively. Meanwhile, the composite aerogel of Ru–Co(OH) x @GO, chitosan and carbonylated cellulose nanofiber is prepared by solution blending and freeze drying, and the hydrogen generation rate has 7680 mL min−1 g−1 (retained 69.4%) under the same amount of Ru–Co(OH) x @GO. Furthermore, after high speed catalytic hydrogen generation, the aerogel can still maintain its structural integrity, thus facilitating recovery and reuse, which is attributed to the co-structural coupling of carbonylated cellulose nanofiber and chitosan macromolecule to the skeleton. This work provides a convenient and controllable strategy for the development of monolithic catalysts. • ZIF-67 nanocrystalline was in-situ grown on GO. • Amorphous RuCo(OH) x was transformed by etching. • Composite aerogel displayed lamellar skeleton and porous channel. • The hydrogen generation rate of the aerogel had 7680 mL min−1 g−1. • The aerogel had a complete structure after catalytic hydrogen production. [ABSTRACT FROM AUTHOR]

In this work, in situ-generated cobalt oxide was infused into g-BCN to fabricate a heterocomposite (CoBCN) with multiple active sites. The electronic structure of CoBCN was further modified via the introduction of n- (Ni) and p-(Fe) type metals to investigate the activities of CoBCN-type materials with loosely bound electrons for electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) which symbolize the reduction/oxidation of water and reduction of fuel gas oxygen that goes on in concurrent electrocatalytic and fuel cell. Experimental results indicated that not only the electronic nature of the surface but also the binding energy between the involved metals and intermediates varied accordingly for the association/dissociation steps, resulting in the superiority of p-doped materials in HER and the n-doped material in the OER and ORR. The HER activity was governed by Fe–CoBCN with an overpotential of 97 mV (@ 10 mA cm−2), whereas Ni–CoBCN showed superior performance for the OER and ORR with an overpotential and E 1/2 of 130 mV (@ 10 mA cm−2) and 0.79 V, respectively. p-/n-effect on CoBCN material for its multifunctional electrocatalytic activity for HER, OER and ORR. [Display omitted] • Fe and Ni oxide were doped individually to observe the p-/n-effect. • Fe–CoBCN dominated HER with a low overpotential due to facile Cat-H interaction. • Ni–CoBCN outperformed for OER and ORR with a low overpotential and E 1/2. [ABSTRACT FROM AUTHOR]

Organic metal complexes (OMCs) transport trace metals (e.g. , Co, Ni, Cu) from surface soils, via the unsaturated zone, to sites of cave carbonate (speleothem) formation. OMCs clearly imprint on speleothem trace element chemistry, but the role of kinetic factors in the signal transfer process has yet to be elucidated. We investigated whether OMCs may viably link metal concentrations in stalagmites and local hydrology (i.e. , drip rate), via their time-sensitive dissociation (or 'decay') in the speleothem water thin-film. We performed competitive ligand exchange experiments using water and soil samples from eight geographically diverse Aotearoa New Zealand caves, providing a first comparative characterisation of speleothem-specific OMC kinetics. Critically, this approach corroborated that NOM ligands limit transition metal availability at the dripwater-speleothem interface, exhibiting stabilities on the order Cu ≈ Co > Ni, whereas organic complexation of the alkaline earth metals Mg and Sr was virtually absent. Systematic variations of OMC stability with natural organic matter characteristics were not observed amongst water samples, whilst enhanced complexation was clearly evident in the comparably organic-rich soil extracts. Our results imply that the supply of transition metals to speleothems is inversely related to drip rate, increasing with drip interval via the decay of OMCs. This process appears most sensitive on time-scales relevant to typical speleothem-forming settings (<0 to ca. 40 drips min−1, corresponding to ca. <5.6 mL min−1), and therefore provides a general, mechanistic link to a quantitative proxy of palaeoclimatic cave drip rates. [ABSTRACT FROM AUTHOR]

The main and significant element in the energy system is hydrogen atom. In addition, electrochemical water splitting is among the most crucial approaches for displacing the extensively utilized petroleum and petroleum products. It is crucial to look for effective electro-catalysts to split the water molecule to produce hydrogen. Because of their good conductivity, distinctive outer shell electronic distribution, and various superficial structural nano-morphology, transition metal chalcogenides are very attractive as effective electrocatalysts for hydrogen production. Currently synthesized transition metal-built chalcogens (containing Sulfur, Selenium, and Tellurium) as efficient catalysts for general splitting of target water using hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), have been discussed in this review. [Display omitted] • Transition Metal-Based Chalcogenides as Electrocatalysts. • Electrochemical overall water Splitting with Chalcogenides. • Transition metals catalytic activity as Te < Se < S. • Hydrogen evolution reaction (HER) for hydrogen generation. • Efficient hydrogen production using Nanoscale Chalcogenides. [ABSTRACT FROM AUTHOR]

The hydrogen adsorption capacities of pure and boron doped Y 3 -(C 6 H 6) 2 have been investigated by using density functional theoretical calculations. Y 3 -(C 6 H 6) 2 can adsorb 5H 2 with gravimetric density of 2.3 wt%. When one or two boron atoms are doped, the hydrogen storage capacity of the Y 3 -(C 6 H 6) 2 is not significantly improved. As more boron atoms doped, the hydrogen storage capacity of Y 3 -(C 6 H 6) 2 increases. The gravimetric density of Y 3 –C 7 B 5 H 12 , Y 3 –C 6 B 6 H 12 , Y 3 –C 5 B 7 H 12 Y 3 –C 3 B 9 H 12 , Y 3 –C 2 B 10 H 12 , and Y 3 -CB 11 H 12 exceed the requirements of the US Department of Energy. In Y 3 –C 8 B 4 H 12 , Y 3 -CB 11 H 12 , and Y 3 –B 12 H 12 , some H 2 tend to dissociate and bond atomically on transition atoms in the process of adsorption. Various characterization methods indicate that Y 3 –C 7 B 5 H 12 , Y 3 –C 6 B 6 H 12 , Y 3 –C 5 B 7 H 12 Y 3 –C 3 B 9 H 12 , and Y 3 –C 2 B 10 H 12 have excellent performance in reversible hydrogen storage, particularly the Y 3 –C 7 B 5 H 12 and Y 3 –C 6 B 6 H 12. [Display omitted] • Hydrogen storage capacity of boron doped Y 3 -(C 6 H 6) 2 can be improved up to 6.4%. • The average adsorption energy of pure and boron doped Y 3 -(C 6 H 6) 2 are 0.21–0.38 eV/H 2. • All results show that Y 3 –C 7 B 5 H 12 and Y 3 –C 6 B 6 H 12 are good candidates for H 2 storage. [ABSTRACT FROM AUTHOR]

Harnessing the power of sustainable hydrogen energy requires the development of efficient, non-precious metal electrocatalysts for water splitting. 2D materials, particularly MXenes offer potential solutions, given their unique attributes like metal-like conductivity, hydrophilic surfaces, and rich chemistry. In this research, we synthesized NiO@V 2 CT x , a novel bifunctional electrocatalyst with a synergistic three-layer structure. This composite merge the tunable properties of V 2 CT x MXene with the catalytic capability of NiO nanoparticles. By varying the NiO concentrations, we synthesized four distinct composites, each showing unique electrochemical characteristics. The 7.5 % composite (VN3), in particular, exhibited superior electrochemical performance with overpotentials of 253 mV (HER) and 346 mV (OER), along with Tafel slopes of 104 mV/dec and 91 mV/dec, respectively, to reach a benchmark current density of 10 mAcm−2. However, higher concentrations lead to blockage of active sites that diminish performance. The low charge transfer resistance (11.33 Ω) of the Ni-adsorbed V 2 CT x MXene contributes to the rapid reaction kinetics and enhanced performance. The composite displayed exceptional durability, indicating its potential for long-term application. It maintained a high current retention of 93 %, indicating outstanding electrochemical stability. Moreover, the cell configuration using NiO@V 2 CT x //NiO@V 2 CT x requires a cell voltage of 1.75 V for overall water splitting. In essence, the VN3 composition was found to be the "sweet spot" for achieving optimal electrochemical performance, potentially offering benefits like high catalytic activity, enhanced conductivity, and improved durability. • First report on synthesis of NiO@V 2 CT x composite. • Material exhibited superior electrochemical performance. • The composite showed exceptional durability and high current retention. [ABSTRACT FROM AUTHOR]

Hydrogen is currently recognized as being able to mitigate the overuse of fossil fuels and as a clean energy source in future development. In addition, water electrolysis can work with renewable energy sources to make the hydrogen cycle sustainable. However, hydrogen production efficiency from water electrolysis relies on efficient catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At present, in order to further develop overall water splitting (OWS) catalysts, non-metal doping has attracted increasing attention. Non-metals can modulate the electronic structure, lattice structure, and surface properties of transition metal-based catalysts, which can be a new strategy to regulate the catalytic activity. Herein, the recent research progresses of non-metallic doping in transition metal-based catalysts are reviewed in this paper. This article summarizes the inherent correlation between the electronic structure and local environmental changes of water electrolysis catalytic materials with different non-metallic elements in the transition metal-based materials. Then, the reasons and related mechanisms for the improved performance of catalysts by nonmetal doping are discussed. The aim of this review is to offer some insights in favour of the role that non-metallic doping owns special advantages in electrocatalytic water splitting. • Non-metals doping is a new strategy to regulate the catalytic activity. • Non-metals can modulate the structure and surface properties of transition metal-based catalysts. • Non-metals doping can regulate inherent correlation between the electronic structure and local environmental. • The effects of non-metal doping on HER, OER and water splitting are discussed. [ABSTRACT FROM AUTHOR]

Photo-assisted electrocatalysis is a frontier direction of electrocatalysis in recent years, which is based on the synergistic effects of electrical and optical energy, providing a new strategy to improve the oxygen evolution reaction (OER) performance. The development of photo-assisted electrocatalysts for OER with high activity and long-term stability is of great significance for hydrogen production through water splitting. In this work, the CoO/NiFe LDH heterojunction are prepared as a photo-assisted electrocatalysts for the first time to enhance OER performance. The strong electron coupling between CoO and NiFe LDH is beneficial to change the electronic structure of catalyst and promote OER. Meanwhile, under illumination, NiFe LDH suppresses the photogenerated charge recombination of CoO and accelerates the charge transfer to promote the accumulation of holes in the CoO valence band, which can be used to further improve its OER performance. The CoO/NiFe LDH requires only an overpotential of 230 mV to achieve 10 mA cm−2 under illumination, which is 60 mV lower than that without irradiation. For water splitting, CoO/NiFe LDH heterojunction only requires 1.57 V (without light) and 1.52 V (with light) to achieve 10 mA cm−2, which is superiors to RuO 2 and most NiFe LDH based materials. Even under the irradiation of low-power LED strip, the CoO/NiFe LDH can still exhibit excellent water splitting performance and long-term stability. This work adopts a promising photo-assisted electrocatalytic strategy to promote the efficiency of water splitting, and boosts the development of LDH-based two-dimensional materials in the field of photo-assisted electrocatalysis. The synergistic effect of CoO/NiFe LDH heterojunction suppresse the photogenerated charge recombination and accelerate the charge transfer to promote the accumulation of holes in the valence band of CoO, making CoO/NiFe LDH exhibit enhanced OER performance. [Display omitted] • CoO/NiFe LDH heterojunction synthesized for photo-assisted electrocatalytic OER. • The strong electron coupling of CoO/NiFe LDH improves OER performance. • The holes accumulated on the CoO further boosts the OER performance. • CoO/NiFe LDH can be applied to the overall water splitting under illumination. [ABSTRACT FROM AUTHOR]

Effects of setting temperatures (T set = 310–350 °C) and hydrogen flow rates (H 2 -FR = 0.2–0.6 standard L/min, SLM) on kinetics and reaction mechanisms during dehydrogenation of Mg-Fe-Ni-H based tank are investigated. Mg 2 FeH 6 -Mg 2 NiH 4 composite under 1:1 mol ratio (∼60 g) is packed in a small hydrogen storage tank with a packing volume of ∼96 mL. The experiment with high operating temperature, resulting in the enhanced decomposition rate requires fast H 2 -FR to reach the best dehydrogenation kinetics. In the case of de/rehydrogenation mechanisms, dehydrogenation under fast H 2 -FR leads to individual decomposition and reversibility of Mg 2 FeH 6 and Mg 2 NiH 4. The experiment under slow H 2 -FR hinders the decomposition of Mg 2 FeH 6 and favors the formation of Mg 2 Fe (1-x) Ni x H 6 via the reaction between Mg 2 FeH 6 and Mg 2 Ni during dehydrogenation. The reversibility of Mg 2 Fe (1-x) Ni x H 6 is accomplished by hydrogenation of Mg 2 Ni + Fe + Mg, benefiting the utilization of unreacted Fe upon cycling. [Display omitted] • Mg-Fe-Ni-H is for the first time upscaled to small hydrogen storage tank. • Operating temperatures and H 2 release rates affect kinetics and reaction pathways. • Temperature and H 2 release rate are optimized for the best desorption kinetics. • At constant temperature, de/rehydrogenation mechanisms alter with H 2 release rates. • Formation and reversibility of Mg 2 Fe (1-x) Ni x H 6 depend on H 2 release rate and favor Fe utilization upon cycling. [ABSTRACT FROM AUTHOR]

A larger overpotential being needed to drive overall water splitting, the poor stability of electrode materials and high cost caused by the scarcity of noble metal electrocatalysts are still important factors for restricting electrochemical water splitting. Developing high-activity, low-cost electrocatalysts to enhance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is a major challenge for overall water splitting. For this purpose, the S–Ni(Fe)OOH electrocatalyst was synthesized and used to perform HER and OER in 1.0 M KOH solution. The experimental results show that the overpotential of S–Ni(Fe)OOH is 22 mV and 198 mV, and the Tafel slope is 93.21 mV dec−1 and 17.50 mV dec−1 for HER and OER respectively. Electrochemical impedance spectroscopy (EIS) also shows that S–Ni(Fe)OOH has smaller R ct value of 2.71 Ω (HER) and 5.492 Ω (OER). The electrochemical active surface areas (ECSA) of S–Ni(Fe)OOH are 55.75 cm2 (HER) and 85.75 cm2 (OER), respectively. In addition, cyclic stability and chronoamperometry (i-t) tests prove that S–Ni(Fe)OOH catalyst has good stability with retention rates of 73.83% and 73.73% for HER and OER, respectively. In conclusion, the optimal S–Ni(Fe)OOH electrocatalyst exhibits a superior HER and OER activity, and can be used as a bifunctional electrocatalyst for the overall water splitting. [Display omitted] • S–Ni(Fe)OOH shows the ultra-low overpotential of 22 mV and 198 mV for HER and OER, respectively. • The cell voltage maintains ∼94.30% of the initial performance after the durability test. • The cell in two-electrode system shows a high energy efficiency in overall water splitting. [ABSTRACT FROM AUTHOR]

In this study, spinel Ni 0.5 Zn 0.5 Fe 2 O 4 doped with transition metal ions as well as rare-earth ions Ni 0.4 Zn 0.4 M′ 0.2 Fe 2 O 4 (M′ = Cu, Dy, Gd and Lu) and M″ 0.5 Zn 0.5 Fe 2 O 4 (M″ = Ni, Mn and Co) are developed using the sol-gel auto-combustion route, and the role of substitution on electromagnetic properties is investigated. The powder X-ray diffraction accompanied by Rietveld refinement signifies a single-phase spinel ferrite that belongs to Fd- 3 m space group for all the compositions. Rietveld refinement confirms that doped Cu2+, Dy3+, Gd3+ and Lu3+ ions are at random distribution between spinel tetrahedral and spinel octahedral sites against their preferential occupancy. The saturation magnetisation (M S) of Ni 0.5 Zn 0.5 Fe 2 O 4 (M S = 50.5 emu/g) increased with partial doping showing M S = 60.08 emu/g for transition-metal doped Ni 0.4 Zn 0.4 Cu 0.2 Fe 2 O 4 and M S = 109.7 emu/g for rare-earth doped Ni 0.4 Zn 0.4 Dy 0.2 Fe 2 O 4 , which was the highest among all the doped compositions. Doping enhances the dielectric permittivity of Ni 0.5 Zn 0.5 Fe 2 O 4 from 4.2 to 6.5 for Ni 0.4 Zn 0.4 Cu 0.2 Fe 2 O 4 and 7.7 for Ni 0.4 Zn 0.4 Dy 0.2 Fe 2 O 4. Further, the reflection coefficient (R L) of all the doped compositions of Ni 0.4 Zn 0.4 M′ 0.2 Fe 2 O 4 (M′ = Cu, Dy, Gd and Lu) was less than −8 dB (85% absorption) throughout the frequency band of 8–12 GHz with an optimum material thickness of 3.5 mm. Transition metal ion doped Ni 0.4 Zn 0.4 Cu 0.2 Fe 2 O 4 resulted in further improvement of its absorption characteristics of the incident EM waves with reflection coefficient (R L) less than −10 dB (between 84.15% and 90%) between 10 and 12 GHz at a material thickness of 3.5 mm in the X-band frequency range. [ABSTRACT FROM AUTHOR]

The design of non-precious electrocatalysts with high performance is essential for developing green and renewable energy sources. Here, we presented a facile method for the synthesis of three-dimensional (3D) phosphorus-doped reduced graphene oxide (P -rGO) assembled by metal/molybdenum layered double hydroxide (M/Mo LDH), where M is Ni, Co, Fe, Cu, Zn, Mn, W, and V. The 3D structure of P -rGO provides abundant active sites for the hydrogen evolution reaction (HER). Among the mentioned metals, nickel shows the best HER performance, presenting a low overpotential of 91 mV at 10 mA cm−2 with a Tafel slope of 56 mV dec−1 in alkaline media. The Ni/Mo LDH@P-rGO electrocatalyst delivers excellent stability after 1000 consecutive cycles and after long-term testing over 12 h. The satisfactory HER activity of Ni/Mo LDH@P-rGO is due to its high electrochemically active surface area and synergistic effects between Ni and Mo atoms. This study will present a simple and efficient strategy to fabricate a high-performance electrocatalyst for HER. [Display omitted] • A facile method for synthesis of 3D- P -rGO assembled by metal/Mo LDH is presented. • The P -rGO 3D-structure provides abundant active sites for the hydrogen evolution reaction. • From them, nickel shows best HER performance, with low overpotential with a slighter Tafel slope. • Ni/Mo-LDH@P-rGO delivers excellent stability after 1000 consecutive cycles over 12 h. • This study presents an efficient strategy to fabricate a high-performance electrocatalyst for HER. [ABSTRACT FROM AUTHOR]

The CO-SCR technology based on transition metal is of great significance for NO x removal in large-scale industrial production. However, excess oxygen usually hinders the deNO x reaction in the actual industrial process. In this paper, a series of Mn-based catalysts modified by transition metals (Fe, Ni, Cu) were prepared using the co-precipitation method, which aimed to obtain good CO-SCR performance under O 2 -rich condition. The results showed that the Cu-Mn 2 sample exhibited excellent deNO x performance. Regardless of the presence or absence of oxygen, the NO conversion of Cu-Mn 2 catalyst was remain about 60% and 95% at 350 and 400 ℃, respectively. Differently, the NO conversion of Fe-Mn 2 catalyst significantly increased from approximately 10% to 61% at 400 ℃ after introducing oxygen, which proved that excess oxygen could promote the CO-SCR process over Fe-Mn 2 sample. The varied physical and chemical properties of the prepared materials were thoroughly evaluated through BET, SEM, XRD, XPS and in situ DRIFTS technologies. The results demonstrated that perovskite α-Mn 2 O 3 , decahedral Mn 5 O 8 , Fe 2 O 3 and Fe 3 O 4 crystals were the dominant structures promoting deNO x reaction on the Fe-Mn 2 catalyst. The oxidation of low valence nitrogen oxides by decahedral Mn 5 O 8 on Fe-Mn 2 catalyst was an important factor for oxygen resistance. And the various spinel structures over Ni-Mn 2 , and Cu-Mn 2 indicated strong synergistic effects. For the Cu-Mn 2 catalyst, the strong synergistic effect of Cu-□-Mn species could promote the dissociation of intermediate -NONO. O 2 tended to occupy the surface synergetic oxygen vacancies in Cu-□-Mn species at high temperatures, which could inhibit the dissociation of -NONO and enhance the CO oxidation reaction. The possible reaction mechanisms for CO-SCR over Mn-based catalysts were discussed specifically. [ABSTRACT FROM AUTHOR]

Transition metal doped carbon materials such as carbon nanotubes and fullerenes have been extensively investigated for hydrogen adsorption and storage applications. However, the strength of these hydrogen storage material is mainly dependent on the metal-support and hydrogen-metal interaction energies. In this work, we have designed, and explored transition metal doped C24 (TM@C24) complexes as single atom catalysts for hydrogen dissociation. Adsorption energy results for all studied TM@C24 complexes reveal the high thermodynamic stability of designed TM@C24 catalysts. Among all considered TMs@C24 catalysts, the highest adsorption energy (−6.22 eV) is calculated for Mn@C24 catalyst. Moreover, H 2 dissociation mechanism is evaluated for both gas phase and in aqueous media to get insight into the solvent effect. In both gas phase and in aqueous media, the best catalytic activity for hydrogen dissociation is computed for Mn@C24 catalyst with the lowest energy barrier of 0.04 eV and 0.30 eV, respectively. NCI analysis is carried out to confirm the shared shell interactions (covalent interactions) between adsorbed hydrogen and TM@C24 complexes. Furthermore, natural bond orbital and electron density differences analysis are also performed to explore the activation and dissociation of H 2 molecule. Overall results reveal that Mn@C24 complex can at as a promising low cost, highly abundant and noble metal free single atom catalyst to effectively catalyze hydrogen dissociation reaction. • First row transition metal doped C24 complexes are theoretically investigated for hydrogen dissociation reaction. • The transition metal act as an active center for the dissociation of hydrogen molecule. • Hydrogen dissociation is proceeded through homolytic cleavage or oxidative addition of H 2 molecule. • Mn@C24 catalyst has the best catalytic activity with the lowest energy barrier of 0.04 eV. • NBO and EDD analysis show the transfer of charge participated in dissociation process. [ABSTRACT FROM AUTHOR]

For the growth of hydrogen energy, it is essential to create electrocatalysts that are affordable, effective, and stable. The transition metal high-entropy boride electrocatalyst is synthesized with the molten salt-assisted boron thermal reduction method. It discusses the influence of element composition, temperature, and the ratio of salt to material on electrocatalytic hydrogen evolution. The results show that WMoVNbMnB synthesized at the ratio of salt to material of 15:1 and sintering temperature of 1000 °C has nano-flake structure. The overpotential at a current density of 10 mA cm−2 at 1 M KOH is as low as 115 mV, with the Tafel slope of 92 mV·dec−1. According to theoretical study, the transition metals (V, Mo, and Mn) are a considerable contributor to the electron around the Fermi level. Under the synergistic effect of multiple components, the V 3d orbit possesses excellent polarization, which thus improves the migration ability of the carrier. In the process of water decomposition, WMoVNbMnB electrocatalyst only needs to cross the 0.24 eV energy barrier to successfully dissociation, with the excellent properties of a glass carbon catalyst. It offers a workable reference for creating water electrolysis technology because of its highly effective catalytic activity. [Display omitted] • High entropy boride catalyst was prepared by one - step sintering method. • Through preparation conditions to change, in order to improve the catalytic performance. • Through the first principle calculation, the hydrogen precipitation capacity of the catalyst is verified. [ABSTRACT FROM AUTHOR]

Here, we report a theoretical design of transition metals (TMs) anchored two-dimensional (2D) holey graphyne (HGY) based catalyst for the hydrogen evolution reaction (HER) through state-of-art density functional theory (DFT) simulation. The studied TMs (Co, Fe, Cr) are bonded strongly on HGY surface due to charge transfer from d orbital of metal to C 2p orbital of HGY. The HGY+TMs systems are stable at room temperature as evident from ab-initio molecular dynamics (AIMD) simulation. We predicted that the Co, Fe and Cr anchored HGY are highly active for HER activity with Gibbs free energy (Δ G) value as low as −0.21, −0.14, and −0.05 eV respectively and which are close to the best-known HER catalyst (Pt metal). The enhanced HER performance is attributed to the increased conductivity as well as redistribution of electrons. As pristine HGY is experimentally synthesized, HGY+TMs (Co, Fe, Cr) systems can be as an efficient catalyst for H 2 production. [Display omitted] • The HER activity of TMs anchored holey graphyne (HGY) is investigated using DFT. • The TMs are strongly bonded with holey graphyne due to p-d hybridization. • The Δ G of Cr anchored HGY is −0.05 eV and close to the best HER catalyst Pt metal. • The enhanced performance of HER activity is due to redistribution of charges. • The Cr anchored HGY can be a promising catalyst for H 2 production. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) is a promising process to produce high purity hydrogen gas. However, the overpotential of this reaction hinders its practical applications. Single atom catalysts (SACs) are recently investigated by the scientific community to facilitate the HER. Herein, we studied the doping of late first-row transition metals on the B 12 P 12 and Al 12 P 12 nano-cages as SACs via density functional theory (DFT) calculations. Results show that all transition metals are chemisorbed on the support, with interaction energies ranging from −0.65 to −3.85 eV. The calculated Gibbs free energies of hydrogen evolution are −0.01, −0.06 and −0.20 eV for Ni@Al 12 P 12 , Ni@B 12 P 12 , and Co@B 12 P 12 , respectively, which are close to the optimum value of 0.00 eV, and comparable to the highly active Pt-based catalysts in literature. Our results indicate that the designed Ni@Al 12 P 12 , Ni@B 12 P 12 , and Co@B 12 P 12 SACs are excellent candidates as noble metal-free, sufficiently stable, and highly efficient electrocatalysts for HER. [Display omitted] • DFT investigation on the application of TM doped nano-cages toward the HER. • Doping of late first-row TMs on B 12 P 12 and Al 12 P 12 is energetically favorable. • Calculated ΔG H∗ are close to the optimum value of zero. • Thermodynamic, QTAIM, DOS, FMO, and NBO analyses are employed to analyze the SACs. [ABSTRACT FROM AUTHOR]

Catalytic converting the lignin-derived bio-oil to liquid fuel is one promising methodology to reduce the dependence on petroleum-based fuel while easing the atmospheric carbon dioxide burden. Hydrodeoxygenation (HDO) is one commonly used method to convert and upgrade bio-oil from biomass. In the present work, a Ru-promoted MoFeP/Al 2 O 3 catalyst was prepared and evaluated the HDO performance by converting two model compounds, guaiacol and anisole with a batch reactor at 250 °C. This catalyst shows a quite good HDO performance over the two model compounds, in which, oxygen was removed from the phenolic and hydrocarbons were produced as the product. Kinetic studies were also performed to build the reaction network and elucidate the reaction pathway of guaiacol and anisole HDO reactions. The primary, secondary, and tertiary products can be identified for the HDO reactions. A better understanding of HDO chemistry from the fundamental study can lead to more efficient catalysts for the target products. [Display omitted] • A highly active Ru-MoFeP/Al 2 O 3 was proposed in HDO reaction. • Reaction network of guaiacol and anisole HDO reaction were proposed. • Primary product, secondary or tertiary products can be identified. [ABSTRACT FROM AUTHOR]

[Display omitted] • Equilibrium CO-adsorbed M–BP configurations are identified by employing DFT embedded semi-automated workflow. • Significant densities of state change upon CO adsorption in M–BP confirms its promising potential for CO detection. • Zn-BP2 could be highly sensitive work function-type sensor for high-temperature CO detection. Our study examines the CO detection capabilities of pristine biphenylene (BP) and transition-metal-doped BP (M–BP x , x = 1 or 2), a novel two-dimensional nano-carbon material. Despite BP's potential in toxic gas detection, its low CO adsorption energy (E ads) of 0.134 eV limits its application. Utilizing a combined strategy of high-throughput computational screening and DFT technique, we accurately identified the ground state configurations of CO-adsorbed M–BP x (M = Sc, Ti, Fe, Co, Ni, and Zn) and confirmed M doping significantly boosts BP's CO adsorption ability, with E ads values ranging from 2.809 to 8.206 eV. This improvement is supported by ab initio molecular dynamics simulations and ionic d-p bonding interactions observed in electron localization functions, densities of state (DOS), and bond population analysis. Additionally, CO adsorption induces notable DOS changes in the M–BP x systems, validating the potential of M–BP x as suitable materials for CO detection. Notably, Zn-BP2 show notable work function shift after CO adsorption (0.36 eV), outperforming pristine BP's 0.30 eV shift, and favorable recovery time (8.940 s). These shifts underscore the potential of Zn-BP2 for work function-based high-temperature CO sensor, marking it as a promising material for sensitive CO detection. [ABSTRACT FROM AUTHOR]

Poplar wood underwent a two-step pressure impregnation with phytic acid-iron and epichlorohydrin-chitosan to boost its flame retardancy while mitigating the loss and mechanical performance issues of conventional treatments. Through chelation and grafting reactions, the stable existence of double chelated transition metal network macromolecules (DCMC) inside the wood was promoted under external heating conditions. Flame retardancy tests, thermal stability analysis, characterization of microstructure and element distribution, functional groups and gas composition analysis showed that the limiting oxygen index of the wood after flame-retardant treatment was significantly improved, with DCMC-Poplar reaching 31.9, and it also met the flame-retardant requirements after the anti-leaching test. Compared to Poplar, the peak heat release rate (HRR) of DCMC-Poplar can be reduced by up to 43.4 %. Under nitrogen and air atmospheres, the residual carbon of DCMC-Poplar, 38.53 % and 20.64 % respectively, was significantly higher than that of untreated poplar, retaining a relatively intact microstructure after combustion. DCMC inhibited the spread of flames and heat transfer by promoting rapid carbonization of the wood material to form a strong flame-retardant layer. Fe3+ catalyzed oxidation to fully combustible gases under low oxygen conditions, reducing the harmfulness of smoke during wood combustion. DCMC were successfully grafted into the wood through C-N bonds, improving the flame retardancy of the wood while avoiding the drawbacks of easy loss and mechanical strength reduction of flame retardants. • Double chelated transition metal macromolecules was synthesized inside the micropores of wood. • DCMC-Poplar had a 39.99 % reduction in total heat releasee (THR)relative to Poplar and an increase in char yield to 38.5 %. • The gas emission behaviors had been elucidated. [ABSTRACT FROM AUTHOR]

• Systematic study of polycarboxylic acid ligands and transition metal complexes. • The fluorescence emission peak of complex 1 has undergone a blue shift. • The magnetic properties of complexes 2 – 8 were studied. In this work, 4-(2-carboxyphenoxy)phthalic acid ligand (H 3 bppa), 4,4′-dipyridyl (4,4′-dipy), 1,10-phenanthroline (phen), 2,2′-dipyridyl (2,2′-dipy) and transition metal ions Zn2+, Cu2+, Mn2+, Ni2+, Co2+ were used to synthesize metal complexes by solvothermal reaction. Ten complexes were synthesized, namely, [Zn(H 2 bppa) 2 (H 2 O) 4 ]·4H 2 O (1), [Mn(H 2 bppa) 2 (H 2 O) 4 ]·4H 2 O (2), [Co(H 2 bppa) 2 (H 2 O) 4 ]·4H 2 O (3), [Mn(H 2 bppa) 2 (2,2′-dipy) (H 2 O)] n (4), [Cu(H 2 bppa) 2 (2,2′-dipy) (H 2 O)] n (5), [Mn 3 (bppa) 2 (4,4′-dipy) 2 (H 2 O) 6 ] n (6), [Co(Hbppa) (phen) 2 (H 2 O)] (7) and [Ni(Hbppa) (phen) 2 (H 2 O)] (8), [Mn(Hbppa) (phen) (H 2 O)] n (9), [Cu(Hbppa) (phen) (H 2 O)] n (10). Structural datas were collected by X-ray single crystal diffractometer, the results show that complexes 1, 2, 3, 7 and 8 are zero-dimensional mononuclear structure, 4, 5, 9 and 10 are one-dimensional chain structure, 6 is three-dimensional network structure. Furthermore, solid state fluorescence properties were performed on complexes H 3 bppa and 1 – 8 , magnetic properties were performed on complexes 2 – 8. The fluorescence experiment results show that the fluorescence intensity of complexes 1 – 8 is weaker than that of H 3 bppa, and the fluorescence emission spectrum of complex 1 undergoes a blue shift relative to the H 3 bppa. Magnetic testing data analysis shows that complexes 2, 3 and 8 have antiferromagentic properties and complexes 4, 5, 6 and 7 have ferromagentic properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Recent research studies have generated stable lead-free inorganic double perovskites halides (A 2 TX 6), replacing Pb2+-containing compounds' risky and unstable structures. The current study thoroughly examines the mechanical, optoelectronic, and thermoelectronic properties of the three perovskites halides Rb 2 TCl 6 (T = V, Cr, Mn) in order to explore their potential applications. The FP-LAPW within the Wien2k computational code was used to apply the generalized gradient approximation (GGA) in the frame of density functional theory (DFT) in order to elucidate the above properties of Rb 2 TCl 6. By using the Charpin and BoltzTraP techniques, we calculated and analyzed the mechanical parameters and thermoelectric properties of Rb 2 TCl 6 , respectively. Additionally, the cubic elastic constants as well as their derivative parameters meeting the ductile nature range were used to validate the durability of the studied materials. The formation energy results indicate that all Rb 2 TCl 6 compounds exhibit mechanical and thermodynamic stability. According to this study, the change of cationic T-site from V to Cr to Mn is mainly responsible for the production of half-metallic (HM) and semiconductor nature in Rb 2 TCl 6. Moreover, the GGA-PBE calculations successfully provided accurate direct band-gaps for the HM (E g = 2.128 eV; T = V) and (E g = 2.111 eV; T = Cr) and semiconductor (E g = 1.2640 eV in spin-up and E g = 1.7010 eV in the spin-down; T = Mn). The calculated optical parameters reveal that the three Rb 2 TCl 6 perovskites demonstrate decent optoelectronic efficiency combined with high conductivity and absorption. These results reveal that perovskites halides are useful materials and candidates for spintronics and optoelectronics devices. Furthermore, the present study elucidates that the temperature-dependent nature of the thermoelectronic properties is due largely to their amazing electronic structures. These Rb 2 TCl 6 materials may find wide use in thermoelectric applications, as evidenced by the ideal value of their calculated figure of merit (Z T = 1.0). • Mechanical, optoelectronic and thermoelectronic properties of Rb 2 TCl 6 are investigated. • Rb 2 TCl 6 [T = V, Cr, Mn] exhibit mechanical and thermodynamic stability. • FM phase Rb 2 TCl 6 shows HM [T = V, Cr] and direct band-gap semiconductor [T = Mn]. • Thermoelectronic materials of Rb 2 TCl 6 show ideal figure of merit (Z T = 1.0). • Rb 2 TCl 6 are suitable materials for optoelectronics and thermoelectronics. [ABSTRACT FROM AUTHOR]

This paper approaches the effect of the transition metal (TM) (Fe, Mn and Co) doping on the stability and the electronic properties of the SiC-based graphenylene (IGP-SiC). All TM dopants were shown to be more favorable at the Si site. The TM-doped IGP-SiC structures exhibit negative cohesive energies and remain in their shapes after ab-initio molecular dynamics simulations (300K), indicating both energetic and thermal stability, respectively. The band gap of IGP-SiC, 3.15 eV, is significantly affected by the TM doping, achieving energies of 1.27, 2.58 and 1.23 eV for Fe, Mn and Co, respectively, for the spin alpha channel. The substitutional doping enhances the surface reactivity, since the work function changes from 5.83 eV (IGP-SiC) to 5.44 (Fe), 5.39 (Mn) and 5.33 eV (Co). Our findings report that TM doping is an effective strategy to modulate the electronic properties of IGP-SiC, leading to a promising use in spintronics and optoelectronics. [ABSTRACT FROM AUTHOR]

• Aniline; Para -functionalization; Regioselectivity; Transition metal; Catalytic reactions. Controlling the site-selectivity in the C-H functionalization of anilines is one of the great challenges in synthetic chemistry. Considering the numerous applications of aniline derivatives in pharmaceuticals, agrochemicals and advanced materials, the para -selective functionalization of these scaffolds has received much attention. Various synthetic methods on the para -selective functionalization of primary, secondary and tertiary anilines, including electrophilic aromatic reactions, nucleophilic aromatic reactions, oxidative addition, radical addition, and carbenoid addition are highlighted in this review. Anilines are prevalent in pharmaceuticals, agrochemicals and organic materials. Therefore, site-selective C-H functionalization of anilines, especially, NH free anilines is of great importance in organic chemistry. Many advances have been made on the para -selective functionalizations of primary, secondary and tertiary anilines, including electrophilic aromatic reactions, nucleophilic aromatic reactions, oxidative addition, radical addition, and carbenoid addition, which are highlighted in the current review. [Display omitted] [ABSTRACT FROM AUTHOR]

Exploring the therapeutic potential of the hydrazone ligands (1–2) and their transition metal complexes (3–10) against malarial and oxidant dysfunctions. The molecular docking and ADMET studies were performed to examine the medicinal abilities of the compounds. [Display omitted] • Hexacoordinated complexes and their ligand were investigated for antimalarial and antioxidant potential. • Complexes are more potent than ligand. • Complex (10) shows highest potency as pharmaceutical agent. • Molecular docking and ADMET studies well support the in vitro results. Malaria is a leading cause of death in many parts of the world and has a profound impact on public health and poses significant challenges to healthcare systems in endemic regions. Malaria is a severe and sometimes fatal disease caused by Plasmodium parasites and its one significant aspect of malaria pathophysiology is its relationship with oxidative stress, a condition characterized by an imbalance between the production of free radicals and the body's ability to detoxify these reactive products or repair the resulting damage. So, in the present research, to identify effective agents for malaria and oxidative stress, microassay and DPPH protocols were applied to previously synthesized and well characterized octahedral hydrazone ligands (1–2) and their Co(II), Ni(II), Cu(II), Zn(II) metal complexes (3–10), which were derived from 2-methoxy-1-naphthaldehyde, 3,5-bis(trifluoromethyl)benzohydrazide, 3-bromo-5-ethoxy-4-hydroxybenzaldehyde. The biological assessment indicated that complexes (8, 9, 10) were particularly effective in inhibiting malaria and oxidative infections as compared to other compounds. Among these, zinc(II) complex (10) exhibited the highest efficacy for malaria and oxidative stress, with an IC 50 values of 0.59 ± 0.13 and 2.12 ± 0.17 µM which are comparable with quinine and ascorbic acid, correspondingly. Additionally, molecular docking studies against the 8E1Z and 1U5A proteins along with ADMET investigations were also support the superior efficacy of complex (10), demonstrating the lowest binding affinity, favorable binding modes and drug likeness ability. [ABSTRACT FROM AUTHOR]

The ceria-tin/alumina mixed metal oxides (Ce/Sn =1) with different proportions of Fe & Mn dopants were synthesized and investigated in detailed approach for diesel emission reduction. The dopants created structural defects enhancing the oxygen ion mobility for exhaust treatment. The existence of surface-active oxygen sites and oxygen ion vacancy sites generated for charge compensation due to reduction of Ce4+, Sn4+ and dopants incorporation evidenced from XPS analysis. The Mn doped sample holds better physicochemical properties than Fe doped sample. The Mn doped sample with higher surface area of about 101.32 m2 g−1 exhibits greater active sites for better catalytic activity. The redox couples in the Mn-doped sample Ce4+/Ce3+, Sn4+/Sn2+, and Mn3+/Mn2+ helps in oxygen regeneration to contribute to exhaust treatment by oxygen ion conduction from bulk to the surface. This sample exhibited the 92 % of NO x reduction and proved to be a dynamic candidate for diesel emission reduction. [Display omitted] • Fe and Mn dopants insertion in CeO2-SnO2/Al2O3 sample enhances the phase stability. • Mn doped sample possesses the better physicochemical properties than Fe doped sample. • Mn doped sample shows larger surface area of 101.32 m2 g-1 with more number of active sites. • The NOx emission is drastically reduced by the Mn doped sample. [ABSTRACT FROM AUTHOR]

Transition metals are promising catalysts for environmental remediation. However, their low reactivity, poor stability and weak reusability largely limit practical applications. Herein, we report that the electron-rich dissolved black carbon (DBC) incorporated into the nanoscale zero-valent copper (nZVCu) can boost intrinsic reactivity, structural stability and cyclic reusability for superior peroxymonosulfate (PMS) activation and pollutant degradation. A series of refractory pollutants can be effectively removed on the DBC/nZVCu, in comparison with the nZVCu reference. Hydroxyl radical (‧OH) is identified as the dominant reactive oxygen species by electron spin resonance (ESR) and chemical quenching tests, mediated by the metastable Cu(III) as the key reactive intermediate. The electron-rich DBC protects nanoscale Cu from oxidative corrosion to slow down the surface formation of inert CuO layer, rendered by the thermodynamically and dynamically capacitive regulation of corrosive electron transfer from metallic core. By this refining way, the conducive DBC improves the neighboring utilization of reactive electron during metal corrosion, oxidant activation, radical generation and pollutant degradation in Fenton-like catalysis. Our findings suggest that the ubiquitous DBC can be an efficient chelating agent to refine transition metals by serving as the surface deactivator and electron mediator, and take new insights into their environmental and agricultural geochemistry. [Display omitted] • Morphological and structural properties of nano-copper were characterized. • Superior Fenton-like catalysis was validated on engineered copper. • Capacitive regulation of corrosive electron transfer was confirmed. • Reaction mechanisms and reactive sites were elucidated. [ABSTRACT FROM AUTHOR]

High entropy alloy NiMoCoMnLa/CNTs@Ni HER electrocatalyst with core–shell nanostructure supported on carbon nanotubes was prepared by a simple two-step low temperature oil phase method under atmospheric pressure. The core–shell heterostructure effectively adjusts the electron layout, which makes the catalyst show superior performance in alkaline electrocatalytic hydrogen evolution reaction. [Display omitted] • A low temperature oil phase method is used for the preparation of high entropy alloy. • Core-shell nanostructures effectively accelerate electron transport. • The catalyst exhibits excellent electrocatalytic activity and stability in alkaline environment. The high entropy alloy (HEA) composed of five or more elements possesses excellent electrochemical hydrogen evolution reaction (HER) performance in alkaline electrolytic water due to the synergistic action of multiple main elements. However, high-entropy alloy catalysts typically have a single structure, and great challenges remain in designing complex structures (heterostructures) to adjust the electron layout to facilitate water decomposition for hydrogen production. Here, we successfully synthesized NiMoCoMnLa@Ni high entropy alloy (HEA/CNTs@Ni) heterostructures electrocatalysts supported on multi-walled carbon nanotubes (CNTs) by a simple two-step low temperature oil phase method. The results showed that the heterogeneous structure of HEA/CNTs and Ni led to electron reconfiguration and accelerated electron transfer rate as well as the optimized hydrogen adsorption energy and the increased number of active sites of catalyst. Therefore, the catalyst showed high electrocatalytic activity and stability for hydrogen evolution reaction. The overpotential is only 146 mV at 10 mA/cm2 with low Tafel slope of 79 mV/dec in 1 M KOH solution. It is worth noting that the catalyst is maintained at a high current density of 80 mA/cm2 for 24 h, and its current density does not decrease significantly or even shows a trend of enhancement, which effectively improves its HER performance in alkaline solution. This work provides a valuable guidance for fully exploring the potential of HEA catalyst in alkaline electrochemical hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

Four coordination polymer complexes and two dinuclear metallocycles (1 – 6) were comprehensively achieved with these ligands when reacted with Ni(II), Co(II), Ag(II), Cd(II), Zn(II), and Cu(II). Single crystal X-ray diffraction studies revealed that different metal salts reacted with different coordination modes of three ligands which can pursued with different conformations to accomplish distinct 0D to 3D coordination polymeric structures. The hydrogen bonds (C H∙∙∙O) and π···π stacking synergies further contributed to the stabilized crystal lattice structure. It is explicitly observed that the conformation, embracing structure and linking mode of these ligands decides a principal trend to determine the structuring of different coordination polymers. We envisaged that our experimental results fostering the construction of new CPs with specific structure using these large semirigid ditopic ligands. [Display omitted] Four coordination polymers (CPs), namely, {[Ni(L1) 2 Cl 2 ]·(CHCl 3)} n (1), {[Co(L1) 1.5 (NO 3) 2 ]·(CHCl 3)} n (2), {[Ag 2 (L2) 2 (NO 3) 2 ]·(CHCl 3)} n (3), [Cd(L2) 2 (Cl) 2 ] n (4), and two dinuclear metallocycles, namely, {[Zn 2 (L3) 2 (Cl) 4 ]·2CHCl 3 } n (5) and [Cu 2 (L3) 2 (Cl) 4 ] (6), (L1 = 2,2′-bis(pyridin-3-ylmethyl)-[5,5′-biisoindoline]-1,1′,3,3′-tetraone), L2 = 5,5′-oxybis(2-(pyridin-3-ylmethyl)isoindoline-1,3-dione), L3 = 5,5′-carbonylbis(2-(pyridin-3-ylmethyl)isoindoline-1,3-dione)), have been adeptly constructed using solvothermal conditions and successfully delineated by non-destructive single-crystal (X-ray) diffraction. Structural analyses provide insights into a two-dimensional (2D) 44 grid layer of complex 1 and a three-dimensional (3D) 63 network of 2. Additionally, the connection between these two complexes is established via hydrogen bonding (C H···O) to further accomplish a three-dimensional (3D) supramolecular framework system. Similarly, Complex 3 and 4 possess a one-dimensional (1D) wave-like chain and loop-like chains composed of olive-like metallacycle building units, respectively. These chains are bridged by C H···O hydrogen bond and π∙∙∙π stacking interactions to generate 3D supramolecular structure. Finally, complexes 5 and 6 occupies zero-dimensional (0D) square-like array also called as olive-like dimeric M 2 L 2 metallacycles. The distinct structural configurations of the six complexes are in close alliance with different conformations of the N -donor pyridyl ligands and coordination arrangement of the transition metal centers. [ABSTRACT FROM AUTHOR]

The dual MOF framework ZIF-L/X-PBA (X = Fe, Co, and Ni) was formed by combining ZIF-L with Prussian blue (PBA), from which Fe 3 C-NCNT, Co-NCNT, and Ni-NCNT were derived. The effect of NCNT derived from different transition metals PBA on batteries performance was studied. Tests showed that the Li–S batteries using Fe 3 C-NCNT obtained an initial discharge capacity of 1456 mAh g−1 at 0.2 C, while the batteries using Co-NCNT and Ni-NCNT had inferior performance in all aspects compared to Fe 3 C-NCNT. It was found that Fe 3 C-NCNT had the best performance, and that the inhibitory effect of MOF derivatives on LiPS varied due to the different characteristics of the metal centers, but they all could suppress shuttle effect and extend the life of the batteries. • Dual MOF framework ZIF-L/X-PBA was formed by combining ZIF-L with Prussian blue. • Fe 3 C–N-CNT, Co–N-CNT and Ni–N-CNT could suppress shuttle effect and extend cycle life. • Fe 3 C–N-CNT with a superior performance than Co–N-CNT and Ni–N-CNT. [ABSTRACT FROM AUTHOR]

[Display omitted] The properties of SF 6 characteristic decomposition products (SO 2 and SOF 2) adsorbed on intrinsic and transition metal atom modified WSe 2 monolayers were studied based on the first principles. The adsorption structure, adsorption energy, electron transfer, density of states, electron differential density, work function, and desorption properties are comprehensively discussed. In addition, the charge transfer in the adsorption system was qualitatively analyzed by using the frontier molecular orbital theory and energy band. The results show that the pristine WSe 2 monolayer has poor sensing performance for SO 2 and SOF 2. Effective modification methods can significantly increase the adsorption activity of the monolayer surface. The modification methods of transition metal atom adsorption and doping are discussed respectively. The modified monolayer all exhibit good sensing properties compared to the pristine monolayer due to the significant electronic hybridization between the impurity atoms and the gas molecules. Finally, the recovery response time of gas molecules from transition metal atom modified WSe 2 monolayer is evaluated to evaluate its potential application in the detection and removal of fault gases in SF 6 insulation equipment. Our work is not only important for predicting novel transition metal sulfide sensing materials, but also provides theoretical guidance for further developing WSe 2 -based sensors and scavengers for environmental monitoring applications. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) investigation has been done to unravel the adsorption and dissociation nature of hydrogen molecule on 3 d , 4 d and 5 d transition metal (M = Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt or Au) atom doped activated carbon (AC) surface. Transition metal doped AC are found to be active catalyst for storage of hydrogen and also gives the stability of M − H bonds formed after bond breakage of H 2 molecule. Transition metals are found to occupy the position on the five member ring rather than six member ring of the AC. Five member ring of the AC is seen to be more deformed than the six-member ring on metal doping. Higher values of LUMO-HOMO gap and vertical ionization potential and lower electron affinity signify the higher stability of hydrogen molecule adsorbed metal doped AC. Bond length and vibrational analysis of the adsorbed hydrogen molecule suggest the higher activation of hydrogen molecule on AC, where 4 d and 5 d metal doped ACs are found to be more efficient in comparison to 3 d metal. Adsorbed hydrogen molecule on metal doped AC follows dissociation either via spill-over or via normal process. DFT evaluated rate constant and the transition states suggest that Ru, Rh, Os and Ir doped AC are found to be efficient in the dissociation of hydrogen molecule, while, Cu doped AC is seen to be worst in the same reaction. Deformed electron density, HOMO-LUMO isosurface, and density of states confirms the redistribution of electrons among H 2 and metal doped AC surface. ΔG H values of Hydrogen evolution reaction also signifies the greater catalytic activities of Ru and Os supported activated carbon towards HER. [Display omitted] • Computational design of materials based on transition metal atom doped activated carbon surface towards H 2 adsorption, storage and H─H activation. • Catalyst designing for Hydrogen Evolution reaction. [ABSTRACT FROM AUTHOR]

In the present work, the effect of transition metals (Ni, Fe, Co) doping on 2-dimensional (2D) molybdenum disulfide (MoS 2) nanosheets for electrocatalytic hydrogen evolution reaction (HER) was explored. A simple and cost-effective hydrothermal method was adopted to synthesis transition metals doped MoS 2 nanosheets. The morphological and spectroscopic studies evidence the formation of high-quality MoS 2 nanosheets with the randomly doped metal ions. Notably, the Ni–MoS 2 displayed superior HER performance with an overpotential of −0.302 V vs. reversible hydrogen electrode (RHE) (to attain the current density of 10 mA cm−2) as compared to the other transition metals doped MoS 2 (Co–MoS 2 , Fe–MoS 2). From the Nyquist plot, superior charge transport from the electrocatalyst to the electrolyte in Ni–MoS 2 was realized and confirmed that Ni doping provides the necessary catalytic active sites for rapid hydrogen production. The stable performance was confirmed with the cyclic test and chronoamperometry measurement and envisaged that hydrothermally synthesized Ni–MoS 2 is a highly desirable cost-effective approach for electrocatalytic hydrogen generation. [Display omitted] • This work explores the effect of transition metal doping on MoS 2 nanosheets for HER. • Ni–MoS 2 displayed superior HER performance with an over-potential of −0.302 V vs. RHE. • Ni doping provides the necessary catalytic active sites for rapid hydrogen production. • Chronoamperometry measurement shows a stable performance of Ni–MoS 2 nanosheets. [ABSTRACT FROM AUTHOR]

Various transition metals were employed to enhance the catalytic performance and N 2 selectivity of Mn-based catalysts. The modification of Fe and Cu promoted the low-temperature activity, while the Al-modified catalyst displayed the highest N 2 selectivity close to 100 %. The characterization results proved that the content of O β and Mn4+ were increased after adding transition metals. N 2 selectivity experiments revealed that the reduction of NO to N 2 O and the oxidation of NH 3 to N 2 O did not occur. The product of NH 3 oxidation was only N 2. Combined with the results of the in-situ DRIFTS experiments, it was proposed that N 2 O was generated from the decomposition of NHNO and NH 4 NO 3 in the SCR reaction. The poor N 2 selectivity of the unmodified catalyst was related to the existence of inactive N 2 O 2 2- species on the surface, while the high content of active NH 2 - species on the Mn 0.1 Ho 0.005 Ce 0.015 Al 0.01 /TiO 2 catalyst enhanced its catalytic activity and N 2 selectivity. In addition, the results also revealed that only the E-R mechanism existed on the unmodified catalyst, while both the E-R and L-H mechanism were activated after the transition metal modification. The SCR reaction of NH 3 and NO proved to be the source of N 2 O. The activation of the L-H mechanism might play a key role in the improvement of activity and selectivity. [Display omitted] [ABSTRACT FROM AUTHOR]

Magnesium hydroxide (MgH 2) has excellent reversibility and high capacity, and is one of the most promising materials for hydrogen storage in practical applications. However, it suffers from high dehydrogenation temperature and slow sorption kinetics. Rare earth hydrides and transition metals can both significantly improve the de/hydrogenation kinetics of MgH 2. In this work, MgH 2 –Mg 2 NiH 4 –CeH 2.73 is in-situ synthesized by introducing Ni@CeO 2 into MgH 2. The unique coating structure of Ni@CeO 2 facilitates homogeneous distribution of synergetic CeH 2.73 and Mg 2 NiH 4 catalytic sites in subsequent ball milling process. The as-fabricated composite MgH 2 -10 wt% Ni@CeO 2 powders possess superior hydrogenation/dehydrogenation characteristics, absorbing 4.1 wt% hydrogen within 60 min at 100 °C and releasing 5.44 wt% H 2 within 10 min at 350 °C. The apparent activation energy of MgH 2 -10 wt% Ni@CeO 2 is determined to be 84.8 kJ/mol and it has favorable hydrogen cycling stability with almost no decay in capacity after 10 cycles. The unique coating structure of Ni@CeO 2 facilitates homogeneous distribution of synergetic CeH 2.73 and Mg 2 NiH 4 catalytic sites, bringing significant improvement in hydrogen storage performance for MgH 2. [Display omitted] • The unique coating structure of Ni@CeO 2 facilitates distribution of CeH 2.73 and Mg 2 NiH 4 catalytic sites. • E a is determined to be 84.8 kJ/mol, 85.1 kJ/mol lower than pure MgH 2. • MgH 2 -10 wt% Ni@CeO 2 can uptake 4.1 wt% H 2 within 60 min at 100 °C under 3 MPa H 2. [ABSTRACT FROM AUTHOR]

Achieving high catalytic performance with the lowest cost is critical for hydrogen evolution reduction. In recent years, biomass-derived carbon catalysts have triggered huge interest in catalytic reactions owing to the low cost, high energy conversion efficiency and environmental friendliness. A rapid growth of novel electrocatalysts is witnessed especially those based on non-precious metals, some of which approach the activity of precious metals. Synergistic interactions between metals and heteroatoms can significantly improve the electrocatalytic activity, thus transition metal-decorated biomass-based carbon materials were commonly adopted to improve HER performance. The resulting electrocatalytic activities are introduced and compared to conventional Pt/C-based electrocatalysts in present research. Moreover, the remaining challenges in the development process and future prospects of hydrogen evolution reduction catalysts are discussed. • The advantages, synthetic methods of biomass-based catalysts for HER were summarized. • The transition metals in different forms can promote the electrocatalytic activity. • The challenges in the development process and future prospects were discussed. [ABSTRACT FROM AUTHOR]

Undoped, doped and co-doped vertically aligned ZnO nanorods (NRs) are synthesized using sonicated sol-gel immersion method. A significant variation in structural, morphological, optical and photoconductivity properties of ZnO NRs after incorporation of transition metal ions (Fe or/and Ag) is obtained. XRD analysis revealed that incorporation of Fe ameliorates while that of Ag deteriorates the c-axis growth of NRs. The diameter of the NRs is tuned from 236 nm to 103 nm. The Fe-doped ZnO NRs exhibit significantly thinner diameter, longer length, and highest aspect ratio. The doping and co-doping reduces the optical band gap of ZnO by 20 meV and 10 meV respectively. A reduction in near band edge emission whereas enhancement in defect-related-green-emission is obtained. Noticeable enhancement in the light harvesting efficiency and significant quenching of the persistent photoconductivity is obtained by co-doping. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cost-effective synthesis of transition metal based ternary metal sulphide microsphere as electrocatalyst. • Electrochemical measurement was performed using polymer electrolyte membrane (PEM) system. • A comparative electrochemical study of synthesized ternary microsphere for HER. • CuCo 2 S 4 shows strong electrocatalytic activity in compare to other electrocatalyst. The production of hydrogen as a clean energy source by a facile method are major concern and promising research area now a days. The electrolysis of water to generate hydrogen and oxygen as a fuel are challenging renewable energy technology. To develop a highly efficient low-cost non-noble metal-based catalyst for hydrogen evolution reaction (HER) is essential and urgent need. Thus, the present work describes a facile synthetic approach to develop suitable cost effective electrocatalyst for water splitting application. It deals one-pot synthesis of low-cost transition metal based ternary metal sulphide (BMS) CuCo 2 S 4 , CuMn 2 S 4 , CuNi 2 S 4 , and CuZn 2 S 4 microspheres as electrocatalyst to generate hydrogen from water. The physical characterization of synthesized electrocatalyst were performed by powder x-ray diffractometer (PXRD) and Raman spectroscopy. The morphological characterization of synthesized electrocatalyst were done by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) however the elemental mapping analysis was done by energy-dispersive X-ray spectroscopy (EDX). The electrochemical measurements were performed in 0.5 M H 2 SO 4 acidic medium on 3-electrode polymer electrolyser membrane water (PEMW) system. The lowest onset and overpotential values have been observed as 61 and 79 mV, respectively in the case of CuCo 2 S 4 micro-sphere. However, the Tafel slope values of CuCo 2 S 4 , CuMn 2 S 4 , CuNi 2 S 4 , and CuZn 2 S 4 electrocatalysts were calculated 121, 115, 102 and 41 mV respectively. On the basis of obtained electrochemical characterization results, CuCo 2 S 4 has been revealed better electrocatalyst under acidic media. This study opens a new direction to consider low-cost transition metal based ternary microspheres as electrocatalyst to produce hydrogen during water electrolysis. [ABSTRACT FROM AUTHOR]

• Graphitic carbon nitride and Fe, Ru & Os embedded gCN is reported for acetone sensing. • The adsorption energy of Fe, Ru and Os embedded gCN, respectively improves to many fold. • Band structure and DOS study also suggested better sensing properties of Fe, Ru & Os embedded gCN. This study investigates the acetone sensing behavior of pristine graphitic carbon nitride (gCN) and group VIII transition metal (Fe, Ru & Os) embedded gCN monolayer using DFT calculations. Key structural and electronic properties such as adsorption energy, band structure, and density of states (DOS) have been examined. The calculated adsorption energy of pristine gCN is −1.32 eV, which improves to –3.52, −2.75, and −1.73 eV for Fe, Ru, and Os embedded gCN, respectively. The band structure also indicates a reduction in the band gap of gCN after acetone adsorption due to the introduction of Fe, Ru, and Os. Furthermore, after the adsorption of acetone, the DOS values exhibit a significant increase from 13.48 eV−1 for pristine gCN to 439, 423, and 332 eV−1 for Fe, Ru, and Os embedded gCN, respectively. [ABSTRACT FROM AUTHOR]

The electronic structures and magnetic properties of two-dimensional MgAl 2 S 4 monolayer, as well as the adsorption configurations, adsorption energy, and charge transfer phenomena of transition metal atoms adsorbed on both pristine and defective monolayer MgAl 2 S 4 surfaces were systematically investigated. The results show that MgAl 2 S 4 at equilibrium is a nonmagnetic indirect semiconductor with a bandgap of 1.908 eV. The adsorption energies of the adsorbed structures on both pristine and defective MgAl 2 S 4 surfaces are negative, indicating good stability for all configurations. The adsorption of transition metal atoms leads to the transformation of the MgAl 2 S 4 monolayer from non-magnetic semiconductor to magnetic semiconductor, bipolar magnetic semiconductor, half-metal, and metal. In addition, there is a good modulation of the bandgap. The significant charge transfer between MgAl 2 S 4 monolayer and the transition metal atoms implies the formation of chemical bonds. The lower work function implies that the MgAl 2 S 4 and transition metal atom adsorption structures benefit electron emission. Thus, research has revealed that the adsorption configurations of transition metal atoms on the surface of MgAl 2 S 4 monolayer offers new possibilities for the fabrication of spintronic devices, the design of highly efficient catalysts, and the application of emission devices. • Adsorption behaviour of transition metal atoms on pristine and defective MgAl 2 S 4 monolayer were studied. • The MgAl 2 S 4 monolayer adsorbed metal atoms showed magnetic semiconductor and half-metallic properties. • Charge transfer between MgAl 2 S 4 monolayer and the transition metal atoms have been observerd. • Some adsorption configurations of MgAl 2 S 4 monolayers have lower work functions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct carbonization of ionic liquids with Fe and/or Cu results in Fe-, Cu-decorated carbons. • Metal nanoparticles' presence and their oxidation states are corroborated. • Bifunctional catalysis of alkaline water splitting by three materials is scrutinized. • Fe,Cu/C exhibits exceptional activity towards oxygen evolution reaction. The quest for highly efficient, stable, and economically viable bifunctional electrocatalysts is of paramount relevance for advancing in water splitting for the hydrogen energy sector, particularly in facilitating hydrogen (HER) and oxygen evolution evolution (OER) as cathodic and anodic reaction, respectively. In this study, two ionic liquids containing transition metal Fe or Cu, as well as a mixture of these ionic liquids, were used as precursors to synthesize Fe-, Cu-, and Fe,Cu-decorated carbon materials through simple, straightforward, and inexpensive carbonization processes. Comprehensive characterization via SEM-EDS, TEM, XRD, and XPS established the formation of Fe 3 O 4 and Cu 2 O species. These materials were systematically evaluated for OER and HER in alkaline electrolyte. Fe,Cu-decorated carbon electrocatalyst exhibited favorable performance for OER, including a low onset potential, and reaching 10 and 50 mA cm−2 at overpotential values of 325 mV and 364 mV, respectively. Notably, grafting both Fe and Cu in the material further augmented its electrocatalytic properties, underscoring the enhanced potential of transition metal-decorated carbon materials for OER applications. [ABSTRACT FROM AUTHOR]

New Co(II), Ni(II), Cu(II) and Zn(II) metal complexes of Schiff base ligands derived by the condensation of 6-aminoindazole with different derivatives of salicylaldehyde were synthesized and characterized. Further compounds were evaluated for antimicrobial, anti-inflammatory, antioxidant and molecular docking studies and findings results revealed that compound 12 exhibit higher potency, against antimicrobial and anti-inflammatory studies, whereas antioxidant activity revealed that the activity of Schiff base ligands enhanced on complexation with transition metal. [Display omitted] • Schiff base-derived hexacoordinated transition metal(II) complexes were synthesized and characterized. • The in vitro antimicrobial, anti-inflammatory and antioxidant activities were performed. • Complex 11 and 12 displayed potent biological activities. • Molecular docking, DFT and ADMET studies validated the in vitro results. Indazoles represent one of the most important heterocycles in drug molecules. Therefore, in the pursuit of potent biological agents, a series of ligands (HL1-HL4) and their corresponding transition metal complexes [M(L1-L4) 2 (H 2 O) 2 ] were synthesized by the condensation reaction of 6-aminoindazole with various derivatives of salicylaldehyde. Further, the compounds underwent characterization through several physicochemical (TGA, powder XRD, SEM, EDAX) and spectroscopic techniques (FT-IR, UV–Vis, NMR, mass spectrometry, ESR). These techniques suggested hexacoordinated stereochemistry of the metal complexes, where ligands chelate via oxygen atom of phenolic ring, azomethine nitrogen and oxygen atom of water molecules in 1:2 (M:L) molar ratio. The thermal stability of the complexes was demonstrated by thermal analysis revealing three step decompositions leaving behind metal oxide as an end residue. The surface morphology of the ligands was distinct from metal complexes as revealed by SEM analysis, while mapping images demonstrated the simultaneously existence of the elements. While, to ascertain the nature of the obtained compounds (crystalline or amorphous), powder X-ray investigation was conducted by utilizing a wavelength of 1.54 Å. The compound's antioxidant potential was assessed through DPPH assays and anti-inflammatory activity was evaluated using BSA denaturation inhibition assay, while their antimicrobial potential was evaluated against six microbial strains (E. coli, S. aureus , P. aeruginosa, B. subtilis , C. albicans, A. niger) by serial dilution approach. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. HL2 (2) and its Cu(II), Zn(II) complexes (11, 12) exhibited potent antimicrobial activity (MIC value: 0.0047, 0.0048 µmol/mL against B. subtilis) and potent anti-inflammatory efficacy (IC 50 value: 6.7 ± 0.044, 6.9 ± 0.036 µM). All the complexes exhibited potent antioxidant activity and their is enhancement in the activity of Schiff base ligands upon complexation, complex (19) demonstrated the greatest activity with IC 50 value 2.1 ± 0.059. Additionally, the ADMET score provided a robust indication of the compounds' drug-like behaviour. Furthermore, the biological effectiveness of the highly microbial potent ligand HL2 (2) and its complexes (9–12) was demonstrated through computational studies. The binding studies exposed that complexes (11, 12) exhibited lowest binding energy at −7.8, −7.9 kcal/mol. While, DFT study emphasized that complex (12) exhibits the highest electrophilicity index value (6.359), suggesting its affinity for binding with biological molecules and also revealed that complexes exhibit greater potency compared to the ligands and could potentially be utilized as drugs for combatting pathogen-induced malformations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Boron nitride nanocages doped with transition metals TM-doped B 12 N 12 (TM = Ag, Au, Pd, Pt and Ru) with Favipiravir drug was studied both in gas phase and liquid phase. • Calculated adsorption energies (E ads), solvation energies (E sol), energy gap (E g), sensing parameter (%ΔE g), NBO analysis, Global descriptors and recovery time were analyzed which strongly support the AgB 11 N 12 nanocage to be potential drug delivery vehicle in the environment. • Charge transfer occurs from the nitrogen atom of the drug to B 12 N 12 and doped nanocages. • Natural population analysis supports that the drug and the nanocages are in non-covalent interaction in nature. The scientific community is keenly interested in developing efficient drug delivery systems using B 12 N 12 , particularly for carrying anti-influenza drugs like Favipiravir (FAV) against life-threatening RNA virus infections. This study delves into the exploration of transition metal-doped B 12 N 12 nanostructures as potential carriers for drug delivery. Using density functional theory (DFT) calculations at the wB97XD/6-311++G(d,p) level of theory, the research specifically investigates the efficacy of transition metal-doped (Ag, Au, Pd, Pt, and Ru) boron nitride nanocages as effective agents for delivering the FAV drug. The systematic exploration of adsorption energy, electronic features, and thermodynamic properties (ΔG and ΔH) of FAV interacting with B 12 N 12 and transition metals-doped (Ag, Au, Pd, Pt, and Ru) nanocages reveals a significant improvement in drug-carrying capacity, marked by notable physisorption capabilities as evident from negative adsorption energies. The confirmation of FAV's interaction with doped-B 12 N 12 nanocages was supported by a comprehensive analysis encompassing frontier molecular orbitals, adsorption energy, fractional charge transfer, molecular electrostatic potential (MEP), non-covalent interaction(NCI), and natural bond orbital (NBO) assessments. The frontier molecular orbitals (FMO), density of states (DOS), and natural bond orbital (NBO) analyses reveal nanocages as charge acceptors and drug as charge donor during the adsorption process. The band gap energies decreased upon FAV adsorption on both pristine and doped nanocages except Au and Pd doped nanocages. Among the doped cases, the Ag-doped B 12 N 12 nanocage exhibits the most significant reduction in the HOMO-LUMO energy difference, and therefore should be the most effective nanocarrier for FAV. The results of this study offer novel insights for the development of B 12 N 12 nanocages as carriers for the FAV drug. [ABSTRACT FROM AUTHOR]