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The surface charges of catalysts have intricate influences on the thermodynamics and kinetics of electrochemical reactions. Herein, we develop a grand-canonical iteration method based on density functional theory calculations to explore the effect of surface charges on reaction kinetics beyond the traditional Butler–Volmer picture. Using the hydrogen evolution reaction on S vacancies of MoS2 as an example, we show how to track the change of surface charge in a reaction and to analyze its influence on the kinetics. Protons adsorb on S vacancies in a tough and charge-insensitive water splitting manner, which explains the observed large Tafel slope. Grand-canonical calculations report an unanticipated surface charge-induced change of the desorption pathway from the Heyrovsky route to a Volmer–Tafel route. During an electrochemical reaction, a net electron inflow into the catalyst may bring two effects, i.e., stabilization of the canonical energy and destabilization of the charge-dependent grand-canonical part. On the contrary, a net outflow of electrons from the catalyst can reverse the two effects. This surface charge effect has substantial impacts on the overpotential and the Tafel slope. We suggest that the surface charge effect is universal for all electrochemical reactions and significant for those involving interfacial proton transfers. [ABSTRACT FROM AUTHOR]

The reduction degree of TiO2 support is critical to the performances of metal catalysts. In many previous theoretical calculations, only the bridge oxygen vacancy (Ov) was considered as the electron-donating defect on reduced rutile TiO2 (r-TiO2−x) supports. However, titanium adatoms (Tiad.), oxidized titanium islands (Tiad.On), and acid hydroxyls (ObrH) also exist at the metal/support interface. By conducting density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, we compared r-TiO2−x surfaces with Ov, Tiad., Tiad.On, and ObrH sites loaded with Au nanoparticles (NPs). The results showed the Au NPs were oxygen-phobic but titanium-philic, resulting in wetting of Ov and Tiad. but short contact with Tiad.On and ObrH. The Bader charges of Au NPs (QM) showed a good linear relationship with the ideal number of donating electrons (Ne) from the defective sites (QM = −KeNe + QM,S), demonstrating the intrinsic electron allocation at the interface. The Ov, Tiad., and Tiad.On exhibited similar slopes (Ke), relatively steeper than that of ObrH. That means in the scope of Au NP charge state, the Tiad. and Tiad.On have a close electron-donating ability with Ov, but the ObrH donates relatively fewer electrons. This linear relationship can be extended approximately to other metals. The higher the metal work function, the steeper the Ke for easier electron donation from defective sites. The stronger the metal oxygen affinity, the more positive the intercept (QM,S). That explains the easy generation of metallic or negative Pt and Au NPs on r-TiO2−x, but hard for Cu and Zn in experiment. That provides theoretical guidance for regulating the charge of metal NPs over TiO2−x supports. [ABSTRACT FROM AUTHOR]

A theoretical study is conducted with three MX3$_{3}$ monolayer 2D materials (AlI3$_{3}$, AsI3$_{3}$, and IrBr3$_{3}$) on their electronic properties and how a halogen monovacancy affects their thermostability. Density functional theory (DFT) calculations are run to obtain the band structures and phonon dispersions for both pristine and defective structures. It is shown that AlI3$_{3}$ and AsI3$_{3}$ have indirect bandgaps of 2.40$2.40$ and 2.23$2.23$ eV, respectively. IrBr3$_{3}$ has a direct bandgap of 1.65$1.65$ eV. Phonon dispersions indicate that they are all thermodynamically stable in pristine state, but their defective counterparts are not. Ab‐initio molecular dynamics (AIMD) simulations are conducted for defective ones to further investigate their stability. It is found that AlI3 and AsI3 layers are decomposed while IrBr3 layer is bent. Further investigations are conducted by analyzing the bond energies and bond lengths of the three materials. It shows that AlI3$_{3}$ and AsI3$_{3}$ have lower bond energy and longer bond length, which makes them dissociated at the ambient temperature while higher bond energy and shorter bond length keep IrBr3$_{3}$ stabilized and enable its displacive phase transition in displacive limit. [ABSTRACT FROM AUTHOR]

Precise regulation on interfacial electronic coupling is essential to achieve efficient catalysts with tailored electrocatalytic behaviors but remains challenging. Herein, a straightforward topochemical strategy is presented to realize Co‐based heterostructured nanofiber stereoassembled with PO coupled nanosheet (CoHF/PO). By constructing well‐defined metal oxide/phosphide interface, prominent electron redistribution can be established via interfacial PO coupling, which is strongly correlated with the catalytic activities. Density functional theory calculations indicate that the rational interface engineering renders accelerated charge transfer and more importantly, optimized surface adsorption/desorption behaviors, contributing to boosted kinetics for both hydrogen evolution reaction and oxygen evolution reaction. Particularly, CoHF/PO featuring promoted intrinsic activity and accessible active sites exhibits intriguing activity and stability at higher current densities in alkaline media, surpassing commercial Pt/C and Ir/C. This study is expected to demonstrate noteworthy promise of covalent coupling toward modulated electronic environment and interface chemistry for electrocatalytic applications and beyond. [ABSTRACT FROM AUTHOR]

The intrinsic charge carriers' recombination and excited states decay greatly suppress the active species survival and photo(electro)catalytic performance. Inspired by Z‐scheme strategy, the polymeric nitrogen‐rich carbon nitride/cadmium sulfide (g‐C3N5/CdS) core–shell heterojunction is constructed to optimize photocatalytic performance. The optimal hydrogen production rate of g‐C3N5/CdS heterojunction catalyst under visible light without adding extra cocatalyst is up to 7860 µmol h−1 g−1, which is 3 and 71 times higher than that of pure CdS and g‐C3N5 photocatalysts, respectively. The femtosecond transient absorption spectroscopy is employed to observe the kinetic decay of carriers in the heterojunction, revealing the ultrafast charge trapping process (τ1 = 52.3 ps) and long‐lived excited states (τ3 = 1109.2 ps) in g‐C3N5/CdS photocatalyst. Meanwhile, density functional theory calculation results comprehensively suggest the promoted charge separation in heterojunction. Cost‐effective Z‐scheme g‐C3N5/CdS photocatalyst in this work shows a great potential for sustainable and high‐efficiency solar‐to‐H2 conversion. [ABSTRACT FROM AUTHOR]

• All dispersants considered acted in synergy with resins in peptizing asphaltenes. • Ionic liquid yielded the best dispersing power and the highest self-association. • Significant electron-withdrawing sites were main contributors to dispersing power. • Steric hinderance associated with molecular structure affected dispersing behavior. In confronting the global climate change, reusing waste asphalt materials stands out as a key strategy for the transportation sector to preserve natural resources and reduce the carbon footprint. Recycling additives or rejuvenators are usually required in this practice, especially for boosting the recycling rate. Given the imperative need for a general compositional design principle of rejuvenators, we previously proposed an innovative formulation concept by combining softeners with asphaltene dispersants, and reported that the use of dispersants largely reduced the total quantity of rejuvenators needed and thus would minimize the environmental impacts. The present study is aimed for probing the molecular mechanisms underlying this observation, with additional interest focused on the synergistic effect of the dispersants with resins and also on the impacts due to their self-association. Selection of representative materials consisted of three types of dispersants including an ionic liquid, a phenolic amphiphile, and an ester plasticizer, in combination with an aromatic oil as the softener. Long-time molecular dynamics (MD) simulation was employed to inspect the aggregation of asphaltenes. Quantum chemical (QC) computation was performed to provide insights into the source of different dispersing behaviors. The results indicated that the three dispersants all acted in concert with resins in dispersing asphaltenes. The dispersion characteristics of asphaltenes could be viewed as a net result of the two competing mechanisms of the dispersing capability and self-association of the dispersant used. The ionic liquid exhibited much higher propensity to self-association at increasing concentrations than the phenolic dispersant, and yet the optimum performance was achieved for both when they were added at low dosages. The ester plasticizer showed minimal self-association and yielded improved dispersion with increasing concentrations. In all cases, the dispersing functionality mainly originated from the presence or formation of significant electron-withdrawing sites, collectively due to the highly electronegative cation and anion, hydrogen bonding, and polar groups. Comparison of the dispersing power was also conducted from different perspectives. The findings are expected to provide molecular insights for formulating versatile and more environmentally benign asphalt rejuvenators. [ABSTRACT FROM AUTHOR]

Iron aluminide (FeAl) inter-metallic compounds are potential candidates for structural applications at high temperatures owing to their superior corrosion resistance, high temperature oxidation, low density and inexpensive material cost. However, the presence of defects can lead to reduction in the strength and ductility of FeAl-based materials. Here we present a density functional theory (DFT) study of the effect of the presence of defects including Fe and Al vacancies as well as H dopants at the substitutional and interstitial sites at a ∑ 5 210 / 1 ¯ 2 ¯ 0 FeAl grain boundary focusing on the energetics. The plane wave pseudopotential code Vienna Ab initio Simulation Package (VASP) in the generalized gradient approximation (GGA) is used to carry out the computations. The formation energy calculations showed that intrinsic defects such as Fe and Al vacancies probably form at the GB, indicated by their negative formation energies. These vacancies can further form defect complexes with H impurities, indicated by lowered formation energies, compact bonds and charge gain of H atoms. Electronic structure analysis showed stronger hybridization of 1s orbitals of H with Fe and Al atoms, which leads to the stabilization of these defects resulting in degradation of material strength. [ABSTRACT FROM AUTHOR]

The presence of a long‐abandoned hexagonal omega (ω) phase in steel samples is recently gaining momentum owing to the advances in transmission electron microscopy (TEM) measurements, even though it is already reported in other transition‐metal alloys. The stabilization of this metastable phase is mainly investigated in presence of C, even though the formation of the ω phase is attributed to the combined effect of many factors, one among which is the enrichment of solute elements such as Al, Mn, Si, C, and Cr in the nanometer‐sized regimes. The present study investigates the effect of the above alloying elements in ω‐Fe using density functional theory (DFT) calculations. It is seen that the magnetic states of the atoms play a major role in the stability of ω‐Fe. Cohesive energy calculations show that the alloying elements affect the energetics and stabilization of ω‐Fe. Further, density of states calculations reveal the variation in d‐band occupancy in the presence of alloying elements, which in turn affects the cohesive energy. Phonon band structure calculations show that only ω‐Fe with substitutional C shows positive frequencies and hence possess thermodynamic stability. Finally, we confirm the existence of ω‐Fe using TEM measurements of a steel sample containing the same alloying elements. Our results can shed light on the stabilization of the ω in other transition‐metal alloys as well, in the presence of minor alloying elements. [ABSTRACT FROM AUTHOR]

[Display omitted] • The work provides a rapid preparation method for defective HKUST-1 with hierarchical micropores and mesopores and Cu1+/Cu2+ mixed-valence sites. • Defective HKUST-1 exhibited specific loading of silibinin A&B with larger molecules from silymarin within 5 min, and high separation efficiency with 91.2% purity after primary separation. • The site competition mechanism for specific recognition and loading of active monomers into mesopores of defective MOF was elucidated at molecular level. • Silibinin A&B preferentially acted on Cu2+ and Cu1+ clusters with the highest binding energy via hydrogen and coordination bonds, respectively. • The separation approach by defective MOF is easy to operate, and requires no specific equipment. Discovering and separating active monomers from natural products is an efficient way to develop new drugs, but faces the difficulty in complex and time-consuming separation process. Metal-organic frameworks (MOFs) are considered a promising separation strategy due to their molecular recognition properties, but their microporous nature poses challenges for capturing most natural compounds with molecule sizes larger than 20 Å. For the first time, this study proposed a simple and efficient approach to separate active monomeric components with larger diameters from structurally similar natural compounds by defect modulation strategy. In this study, defective HKUST-1 with hierarchical microporous/ mesoporous structures and Cu1+/Cu2+ mixed-valence sites was rapidly synthesized. The defective MOF demonstrated specific loading of silibinin A&B from silymarin containing seven structurally similar flavonoids within 5 min, and high separation capacity with the purity of ∼91.2% after primary separation. FTIR, XPS, and DFT calculation revealed the site competition mechanism for specific recognition and loading, where silibinin A&B preferentially acted on Cu2+ and Cu1+ clusters with the highest binding energy via hydrogen and coordination bonds, respectively. Compared to traditional separation techniques, the separation approach via defective MOF shows multiple advantages including high specificity, high separation efficiency, and easy to operate. [ABSTRACT FROM AUTHOR]

• Oxidative aging promoted and further stabilized asphaltene aggregation. • The driving force for aggregation was dispersion between the fused aromatic cores. • All additives reduced asphaltene aggregation and improved orientational randomness. • TBC exhibited the highest potential due to spatial distribution of four polar sites. Economic and environmental sustainability has been a significant stimulus to the use of recycled asphalt materials in the pavement industry. In this practice, rejuvenators are usually required to treat the oxidized asphalts with the aim to restore the physical properties and engineering performance. A critical function required for rejuvenators is that they can deagglomerate the asphaltene aggregates by effectively interacting with them. This study employed the techniques of molecular dynamics simulations and quantum chemical calculations, and investigated the impacts of oxidation on asphaltenes and the deagglomerating potential of three selected additives with different molecular structures and polarities, i.e., tributyl citrate (TBC), limonene, and myristamide. Analyses based on the aggregation number, orientational order parameter, and decomposition of the interaction energy indicated that oxidation strengthened the binding between the asphaltenes and thus promoted their aggregation behaviors. Among the three additives, TBC exhibited the highest rejuvenating effectiveness as it restrained the formation of large asphaltene aggregates and improved the orientational randomness of the aromatic cores. This capability was attributed to the highest number of polar sites in TBC and its three-dimensional spatial structure, which enhanced the compatibility and interactions with the aged asphaltenes. Based on the independent gradient model (IGM) method, the asphaltene aggregation is driven by the π-π interactions dominated by dispersion forces between the fused aromatic cores. The additives weakened the asphaltene interactions to different degrees, but the reversing effects were limited compared to the unaged state. [ABSTRACT FROM AUTHOR]

A theoretical study is conducted with three MX3$_{3}$ monolayer 2D materials (AlI3$_{3}$, AsI3$_{3}$, and IrBr3$_{3}$) on their electronic properties and how a halogen monovacancy affects their thermostability. Density functional theory (DFT) calculations are run to obtain the band structures and phonon dispersions for both pristine and defective structures. It is shown that AlI3$_{3}$ and AsI3$_{3}$ have indirect bandgaps of 2.40$2.40$ and 2.23$2.23$ eV, respectively. IrBr3$_{3}$ has a direct bandgap of 1.65$1.65$ eV. Phonon dispersions indicate that they are all thermodynamically stable in pristine state, but their defective counterparts are not. Ab‐initio molecular dynamics (AIMD) simulations are conducted for defective ones to further investigate their stability. It is found that AlI3 and AsI3 layers are decomposed while IrBr3 layer is bent. Further investigations are conducted by analyzing the bond energies and bond lengths of the three materials. It shows that AlI3$_{3}$ and AsI3$_{3}$ have lower bond energy and longer bond length, which makes them dissociated at the ambient temperature while higher bond energy and shorter bond length keep IrBr3$_{3}$ stabilized and enable its displacive phase transition in displacive limit. [ABSTRACT FROM AUTHOR]

[Display omitted] • The furfural hydrogenation mechanisms are systematically investigated in vapor phase and aqueous phase. • A proton-shuttling mechanism in aqueous phase is proposed. • The presence of water enhances the stability and activity of reaction intermediates. • The dynamic charge separation between the catalyst and the intermediates results in low hydrogenation barriers. The catalytic hydrogenation of biomass-derived compounds in the aqueous phase is crucial to upgrading renewable biochemicals and biofuels. Herein, by combining density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, we have explored the selective hydrogenation mechanism of furfural on the copper surface with a fully explicit solvation model. The presence of water solvent could significantly affect the reaction mechanism, in adjunct with the charge interactions between the reaction intermediates and the Cu surface. It demonstrates a proton-shuttling mechanism for furfural hydrogenation where the initial hydrogen source for reducing the carbonyl group is from the dissociation of the adjacent water. Furthermore, the water solvation effect results in the dynamic charge separation between the copper surface and the reaction intermediates, significantly reducing the energy barrier. These results deepen our mechanistic understanding of selective hydrogenation of furfural over Cu-catalysts, paving the way for upgrading renewable biomass derivatives in applications. [ABSTRACT FROM AUTHOR]

Abstract: Violacein possesses a significant antioxidant activity, which possible relates to its other biological functions. In this study, the hydrogen atom transfer and electron donating ability of violacein is studied by using density functional theory method. The structure of violacein is optimized, and its O–H and N–H bond dissociation energy (BDE), ionization potential (IP) are calculated. The results find violacein has a strong electron donating ability, but a weak hydrogen atom transfer ability. While, its coplanar isomers have the strong hydrogen atom transfer ability as well as electron donating ability. The N7–H7 band plays an important role in violacein`s antioxidant activity. [Copyright &y& Elsevier]

• Innovative introduction of Co element into Na 2 FeP 2 O 7 material using a sol–gel method, as well as the reduction of active particles' size to nano-level and the formation of continuous carbon layer. • Taking advantage of "zero-strain" characteristic. • Enhanced charge/discharge capacity, superb rate capability and ultra-long cycling lifespan with a high capacity retention. • Experimental and theoretical investigation of the effect of Co doping with various measurements, including in-situ/ ex-situ characterizations, FIB-SEM, DFT calculations etc. Na 2 FeP 2 O 7 cathode material exhibits great promise in sodium ion batteries (SIBs), due to its low cost and high structural durability. Nevertheless, the intrinsically poor electronic conductivity and sluggish Na+ diffusion kinetics of Na 2 FeP 2 O 7 hinder its practical application. Herein, a synergistic cooperation of continuous amorphous carbon layer and optimized Co doping strategy is proposed to design high-performance SIB cathode (Co-doped Na 2 FeP 2 O 7 /C) via in-situ sol–gel method, where Co integration significantly enhances both the electronic conductivity and the Na+ diffusion kinetics, as confirmed by the combination of ex/in-situ characterizations and density functional theory calculations. Valuably, the synergy of amorphous carbon layer and appropriate Co doping restrains the structure stress to "zero-strain", Which remains beneficial for 0.10Co-NFO@C to display a high capacity of 96.12 mAh g-1 at 0.05C and a high-rate capacity of 61.75 mAh g-1 at 60C with the capacity retention of 79.9% after 5000 cycles. Moreover, optimized Co-doped Na 2 FeP 2 O 7 /C also shows outstanding cycling performance and rate capability when assembled into full batteries (hard carbon as the anode), demonstrating a reversible capacity of ∼110.9 mAh g-1 at 50 mA g−1, and a respectable capacity retention of 78.0% at 500 mA g−1 for 500 cycles. The strategy inspires new advances towards zero-strained cathode materials for high performance SIBs. [ABSTRACT FROM AUTHOR]

• GaN[0 0 0 1] nanowire is modelled using density functional theory. • Most stable adsorbing sites for Pd and Pt are identified. • Hydrogen dissociates to atoms, while attaching through metals. • Strain on the surface due to bond length changes can be utilized to detect hydrogen. • Lower adsorption energies, lattice strain and charge reconstruction aid H detection. Using density functional theory based simulations, the adsorption of hydrogen on GaN nanowires with [0 0 0 1] orientation is studied with Pt and Pd functionalization. The adsorption energies show that both Pt and Pd prefer to attach to a top site above the Ga atom in the nanowire. In the pristine GaN, hydrogen attach as a molecule, while in the presence of Pt and Pd, it dissociates into atoms and adsorb through a chemical bonding. Change in Ga-N bond lengths are observed with hydrogen adsorption on the surface of the nanowire and the resultant strain as well as the charge transfer between atoms can be used as entities to understand the detection mechanism. From the electronic structure analysis, it is revealed that both Pt and Pd can be used to tune the band gap and are favorable adsorbates to enhance the hydrogen sensing properties of GaN nanowires. Pt turns out to be a more efficient adsorbate for hydrogen detection due to the lowered adsorption energies, compact Pt-H bond length and enhanced surface charge reconstruction. [ABSTRACT FROM AUTHOR]

We present a quantum hash function in a quantum walk framework on Johnson graphs. In this quantum hash function, the message bit decides which coin operator, i.e., Grover operator or DFT operator, is applied on the coin at each step. Then a fixed conditional shift operator is applied to decide the movement of the walker. Compared with existing quantum-walk-based hash functions, the present hash function has a lower collision rate and quantum resource cost. It provides a clue for the construction of other cryptography protocols by introducing the quantum walk model into hash functions. [ABSTRACT FROM AUTHOR]

This paper presents results for four types of morphology-controlled two-dimensional cobalt based tetrakis (4-carboxyphenyl) porphyrin metal-organic frameworks (2D Co-TCPP MOFs) with different catalytic properties for nitrite, and an electrochemical sensor was fabricated by the Co-TCPP MOF with superior catalytic properties. The sensor exhibited a high sensitivity of 311.3 μg/g, an extra low detection limit (LOD) of 0.03 μM, and a wide linear range of 0.1–375 μM, which was applied successfully for nitrite detection in water, milk and sausage. Moreover, density functional theory (DFT) calculations were used to establish the sensing method, the adsorption structures of nitrite on the surface of Co-TCPP MOF were built and the electrocatalytic mechanism was confirmed. The results explained why the sensor fabricated by a single Co-TCPP MOF exhibited equal or better performance than reported sensors fabricated by composite materials based on a combination of theory and experiment. This work reported a universal electrochemical sensing method for nitrite detection in food based on a single morphology-controlled 2D TCPP MOF, which provided a new and valuable strategy for establishing an efficient food safety determination method guided by theoretical calculations. • An ultrasensitive and rapid method for nitrite detection in food is reported. • For the first time, DFT calculation is used for establishment of sensing method. • The method is established based on single morphology controlled 2D Co-TCPP MOFs. • The nitrite sensor exhibits high sensitivity, extra low LOD and wide linear range. • The work provides a new strategy for establishment of food analytical method. [ABSTRACT FROM AUTHOR]

Phase transformation in low alloyed Fe-C steels during quenching and partitioning (Q&P), though authentically attributed to carbon diffusion, is scarcely quantified experimentally in terms of microstructural evolution and lack of fundamental backing at a quantum mechanics level. Herein, we report on a combined in-situ high energy synchrotron X-ray diffraction and density functional theory (DFT) study to unveil the physical mechanism of phase transformation in a Q&P processed advanced Fe-C steel. Beside a small fraction of bainite, a low air-quenching rate of ∼6 °C/s in the M s to quenching temperature range leads to carbon enrichment into the untransformed austenite, which simultaneously turns up with the later stage of martensitic transformation at the existing austenite/martensite interfaces. The resulting transformations are ascertained by DFT results and attributed to a second energy barrier in ferrite/martensite facilitation to carbon diffusion to austenite at elevated temperatures, along with the well-known carbon solubility difference/equilibrium in austenite and martensite. The development of cubic martensite in the carbon steel is theoretically elucidated and attributed to more probable hopping sites and diffusion paths of carbon in the ferrite/martensite than in the austenite. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The geometries, electronic, and magnetic properties of the Au7H n (n =1–10) clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. It is found that the Au7 on the whole retains its triangle structure after hydrogen atoms adsorption and adsorbing hydrogen atoms can stabilize the Au7 structure. The Au7H7 cluster is much higher stability than the neighboring clusters. The pronounced even–odd alternation of the magnetic moments is observed in the Au7H n systems indicating Au7H n clusters possess tunable magnetic properties by adding even or odd number of H atoms. [Copyright &y& Elsevier]

• Ultrathin cobalt carbide (Co 2 C) nanosheets are firstly employed as photothermal catalysts. • Efficient degradation of mustard-gas simulants (CEES) is realized under solar light. • Catalytic performance of Co 2 C is better than nanocrystalline TiO 2 under identical conditions. • Mechanism of photothermal-driven CEES degradation on Co 2 C is clearly revealed. Here, ultrathin cobalt carbide (Co 2 C) nanosheets are firstly illustrated as effective and robust catalysts toward photothermal degradation of sulfur mustard simulants (e.g., 2-chloroethyl ethyl sulfide, CEES) under solar light. Under the optimal conditions, the degradation rate of CEES by Co 2 C nanosheets is up to 98 %, which is much higher than the widely used P25 and anatase TiO 2 nanoparticles. Moreover, the degradation performance is comparable or even better than those typical photothermal catalysts, including MnO 2 , MnO x -TiO 2 and Co 3 O 4 , under identical conditions. Experimental evidences and density functional theory (DFT) calculations reveal that the superior activity is attributed to three main reasons: (i) the high photo-to-heat conversion efficiency of Co 2 C enables an elevated surface temperature for chemical bond breaking, (ii) the feasible binding of CEES on Co 2 C surface via Co S and Co Cl coordination promotes the process of degradation, and (iii) the surface hydroxyl groups (OH) on Co 2 C nanosheets favor the degradation of CEES. Obviously, this work provides new insights into practical and large-scale application of transition metal carbides (TMCs) as novel photothermal catalysts in the decontamination of chemical warfare agents (CWAs) under ambient conditions (i.e., solar light and room temperature). [ABSTRACT FROM AUTHOR]

• 3D I-doped Bi 2 O 2 CO 3 /Bi 2 WO 6 heterojunctions were prepared via facile solvothermal method. • DFT reveals that the doping of I can further narrow the band gap of Bi 2 O 2 CO 3 /Bi 2 WO 6. • Z-scheme photocatalytic system was formed by I-doped Bi 2 WO 6 and Bi 2 O 2 CO 3 , respectively. • I-doped Bi 2 O 2 CO 3 /Bi 2 WO 6 composites show superior photocatalytic efficiency. The Bi-based hierarchical multi-component photocatalytic system is an important player in energy and environmental catalysis due to its full-spectrum light absorption and stable separation of photo-generated charges. In this study, a novel family of iodine doped Bi 2 O 2 CO 3 /Bi 2 WO 6 heterojunctions was successfully developed by a facile ionic liquid assisted solvothermal method. A visible light photocatalytic H 2 production rate of 664.5 μmol g−1 h−1 (0.3I-Bi 2 O 2 CO 3 /Bi 2 WO 6 with 3% Pt) has been durably obtained, much higher than those of pristine and undoped counterparts. The photocatalysts are also capable for persistent pollutant and dye degradation. Through electrochemical and spectroscopic tests and density functional theory calculation, the enhanced photocatalytic activity is attributed to formation of the Z-scheme photocatalyst. Therein, the lowered and indirect bandgap and heterojunctional band alignment spontaneously benefit visible light harvesting, electron-hole pair separation, and proton reduction. Besides a facile synthesis for effective photocatalysis, the Z-scheme mechanism is hoped to facilitate the design and realization of similar systems for photocatalytic H 2 evolution and organic hazards decontamination. [ABSTRACT FROM AUTHOR]

Lead is a prevalent toxic, nonessential heavy metal that has been considered as a major threat for human health. The intention of this work is to study the complexation of flavonoids (apigenin, chrysin, kaempferol and quercetin) with Pb(II) as well as antioxidant activities. The spectroscopy (AAS, UV–Vis, FT-IR, HPLC-MS, 1H NMR) and density functional theory (DFT) calculation were carried out to analyze complexation of flavonoids with Pb(II). In addition, antioxidant abilities of flavonoids were analyzed by FRAP and ABTS assays. The results of study indicate that complexation abilities of kaempferol and quercetin are stronger than apigenin and chrysin. Additionally, the main complexes are formed by reaction of flavonoids (except quercetin) with Pb(II) in a ratio of 2:1. It is indicated that kaempferol and quercetin have a promising prospect of becoming care ingredients for lead elimination. Image 1 • Quercetin has the strongest complexing ability in reaction with Pb(II). • The stoichiometries of the main complexes (except quercetin) are 2:1. • Kaempferol and quercetin still have strong antioxidant capacities after complexation. • Kaempferol and quercetin could be care ingredients for lead elimination. [ABSTRACT FROM AUTHOR]