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[Display omitted] The urgent need to prepare clean energy by environmentally friendly and efficient methods, which has led to widespread attention on electrocatalytic nitrogen reduction reaction (NRR) for ammonia production. At present, single atom catalytic nitrogen reduction has become the earliest promising method for industrial production due to its high atomic utilization rate, high selectivity, high controllability, and high stability. However, how to quickly screen catalysts with high catalytic efficiency and selectivity in single-atom catalysts (SACs) remains a challenge. Herein, the 29 SACs are constructed from C 6 N 2 nanosheets doped with transition metals (TM@C 6 N 2), which are analyzed for stability, adsorption performance, NRR catalytic activity, electronic properties, and competitiveness using first-principles calculations. The results show that Mo@C 6 N 2 and Re@C 6 N 2 exhibit the most outstanding catalytic performances, with limiting potentials (U L) of −0.29 and −0.31 V, respectively, in the solvent model. Machine learning is used to derive descriptors from the intrinsic features to predict the free energy changes for the potential-determining step. The importance of features is calculated, with the first ionisation energy ( IE 1) being the most significant influencing factor. Based on the guidance of machine learning and considering that IE 1 is related to the ability of metal atoms to donate electrons, a four-step screening strategy using the Integrated Crystal Orbital Hamilton Populations (ICOHP) to screen catalysts instead of the traditional five-step screening not only improves the screening efficiency but also obtains completely consistent screening results. This work presents a new approach to predicting the catalytic performance of SACs and provides new insights into the influence of intrinsic properties on catalytic activity. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) has attracted great considerations due to their high toxicity, teratogenicity, and carcinogenicity. In this study, four Zr‐MOFs were synthesized and used to comparative study their catalytic performances of oxalic acid (OA) for Cr(VI) removal. Results showed that the removal efficiency for Cr(VI) was reached 65.91%, 78.64%, 53.58%, and 96.32% by MOF‐525, MOF‐525(Co), MOF‐525(Zn), and MOF‐525(Fe) in the presence of OA when the initial Cr(VI) concentration was 100 mg·L−1, respectively. The single‐factor experiments for further improving the Cr(VI) removal by MOF‐525(Fe)/OA demonstrated that the optimal conditions were OA dosage of 790 mg·L−1, and MOF‐525(Fe) dosage of 500 mg·L−1 and pH of 2.0, and the MOF‐525(Fe)/OA system could be used to treat Cr(VI)‐containing wastewater at concentrations below 50 mg·L−1. Ionic strength studies indicated that Na+, K+, Mg2+, Cl−, and SO42− had little effect on the catalytic reduction of Cr(VI), while high concentrations of Ca2+ (0.10 and 0.25 mol·L−1), NO3− (0.25 mol·L−1), and PO43− (0.25 mol·L−1) had significant inhibition effects. The reusability experiments showed that the stability of MOF‐525(Fe) was excellent, and it could be used for potential applications. Based on the results of Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and Electron Paramagnetic Resonance spectrometer (EPR), the possible reduction mechanism of Cr(VI) by MOF‐525(Fe)/OA system was proposed as follows: The complexation of OA with Fe3+ was first complexed to produce Fe2+ and CO2•−, then Cr(VI) was combined with Zr–O and Fe–O clusters in MOF‐525(Fe) to obtain activation energy, and the reduction ability was enhanced at the same time; finally, Cr(VI) obtained electrons from CO2•− and was sequentially reduced as Cr(V) and Cr(III). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction (SCR) catalysts is used widely to reduce NOx emissions from diesel engines. However, improvements in de-NOx performance are required to meet future standards of near-zero NOx emissions. This study examines the effectiveness of dual-point NH3 injection technology, in which gaseous NH3 is injected into both closed coupled and under floor SCR catalysts. The NOx removal efficiency of dual-point NH3 injection is compared with that of single-point injection in a World Harmonized Transient Cycle test. The results show that dual-point injection of NH3 gas can effectively reduce NOx emissions from diesel engines due to superior temporal and spatial distribution of NH3 gas in an SCR catalyst. [ABSTRACT FROM AUTHOR]

A simple electrochemical sensor was developed towards the widely used insecticide Imidacloprid (IMI) using a redox active polymer, poly(1,5-diaminoanthraquinone) (PDAAQ) modified glassy carbon electrode (GCE). The electro catalytic reduction of IMI was obtained using the GCE/PDAAQ electrode in phosphate buffer solution having pH 7. The irreversible reduction of IMI occurs at a potential of −1.031 V with a slight shift towards negative potential with increase in concentration of IMI. The linear range obtained is 9.98 × 10–6 to 6.6 × 10–4 M with a limit of detection 2.95 × 10–7 M. Repeatability and reproducibility of the sensor was checked and was found to be in the acceptable range with relative standard deviation less than 5%. Selectivity of the sensor was studied in presence of various metal ions and organic molecules and found that there is no significant interference. IMI analysis was done using spike recovery tests in well water and cucumber juice samples which shows that the developed sensor can be successfully applied to the trace determination of IMI in real samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • NO x conversion and N 2 selectivity are significantly enhanced in the presence of SO 2. • The decrease in CO oxidation ability is the main reason for the improvement in NO reduction performance. • L-H reaction pathways for CO oxidation are inhibited by the formation of sulfate species. • The promotional mechanism of SO 2 on CO-SCR reaction over Ir-based catalysts is proposed. Generally, sulfur poisoning is considered to be one of the main factors contributing to the deactivation of selective catalytic reduction of NO x by CO (CO-SCR) catalysts, while the promotional effect of SO 2 on NO reduction over Ir/SiO 2 is observed which is an interesting scientific phenomenon. After the introduction of 20 ppm SO 2 , NO x conversion increased from ∼ 40 % to ∼ 90 % at 275 °C, and N 2 selectivity increased from ∼ 80 % to 100 % at 200 ∼ 300 °C. Furthermore, the promoting effect could remain unchanged after 24 h of continuous reaction. However, the temperature point for achieving complete conversion of CO increased from 225 °C to 275 °C after the introduction of SO 2. Experimental characterization and theoretical calculation jointly proved that the inhibition of CO oxidation by the generation of sulfate was the main reason for promoting NO reduction. Under the coexistence of O 2 and SO 2 , SO 2 was firstly oxidized to SO 3 on the iridium surface and generated sulfate species on surface hydroxyl groups of SiO 2. Some active sites for O 2 adsorption were covered by the generated surface sulfate, and adsorbed CO was hard to react with adsorbed O 2 , resulting in Langmuir–Hinshelwood (L-H) reaction pathways for CO oxidation being inhibited. Therefore, unoxidized CO reacted with NO adsorbed species and generated N 2 O to generate N 2 and CO 2 , improving NO reduction. This new insight has implications for understanding the promotional effect of SO 2 on NO reduction with CO in the presence of O 2. [ABSTRACT FROM AUTHOR]

Although bimetallic noble nanostructures often possess high activity in nanocatalysis, their controllable fabrication, tunable catalytic activity, and easy separation remain significant challenges. In this study, an Fe3O4@AgPd/Polydopamine (Fe3O4@AgPd/PDA) nanosnowman loaded with an AgPd nanocage was designed by a one-step template-disposition-redox polymerization method. The AgPd nanocage endowed the product with high catalytic activity for the reduction of organic pollutants (4-NP, MO, MB). Interestingly, under near-infrared (NIR) light, the catalytic kinetics of the Fe3O4@AgPd/PDA nanosnowman on catalytic reduction of organic pollutants increased by 2.6, 1.57, and 5.45 times, respectively. The asymmetric nanostructure facilitated the separation of electron–hole pairs, promoted electron transfer, and accelerated the catalytic activity. Density functional theory (DFT) analysis indicated that the electron transfer between the AgPd alloy and the Fe3O4 nanosphere played a critical role on the high catalytic activity. Moreover, Fe3O4@AgPd/PDA also demonstrated excellent catalytic activity in the Heck carbon–carbon coupling reaction with a >95% conversion rate and >99% selectivity. Owing to the well-encapsulated PDA shell and outstanding magnetic properties, the Fe3O4@AgPd/PDA nanosnowman exhibited good cyclic catalytic activity. With its multi-mode catalysis, NIR-enhanced catalytic activity, and easy separation, the Fe3O4@AgPd/PDA nanosnowman exhibits great application potential in nanocatalysis. [ABSTRACT FROM AUTHOR]

This article presents the first practical engine system using ammonia (NH 3) as a mono-fuel. To address the low flammability and distinctive odor, the system incorporates a four-cylinder spark ignition engine with an onboard reformer applying autothermal reforming to generate hydrogen as a combustion promoter, a three-way catalyst (TWC), and selective catalytic reduction (SCR) catalyst as an NH 3 adsorbent. The system successfully reduced nitrogen-based exhaust emissions during cold starts, which was a challenge, by controlling the air-fuel ratio (λ). Nitrogen oxides were suppressed by rich combustion until the TWC became active, while NH 3 passing through the TWC was adsorbed by the SCR catalyst. After TWC activation, simultaneous purification of NH 3 and nitrogen oxides was achieved by controlling λ at 1. The adsorbed NH 3 was subsequently purified along with nitrogen oxides via the SCR reaction by lean operation, regenerating the adsorption capacity and achieving near-zero emissions. • An NH 3 mono-fueled engine system with a reformer and an adsorbent was proposed. • Successful cold start-up was achieved with suppressed NH 3 , NO x , and N 2 O emissions. • Rich combustion reduced NO x and N 2 O until a three-way catalyst is activated. • Adsorbed NH 3 was purified with NO x by lean operation using SCR reactions. • Production of N 2 O on TWC was reduced avoiding lean and low temperature conditions. [ABSTRACT FROM AUTHOR]

Although not the only greenhouse gas, CO2 is the poster child. Unsurprisingly, therefore, there is global interest across industrial and academic research in its removal and subsequent valorisation, including to methanol and its surrogates. Although difficult to study, the heterogenous pnictogens represent one important category of catalytic materials for these conversions; their high crustal abundance and low cost offers advantages in terms of sustainability. Here, Zintl clusters based on these elements are studied as homogenous atom-precise models in CO2 reduction. A family of group 13 functionalized pnictogen clusters with the general formula [(R2E)Pn7]2– (E = B, Al, In; Pn = P, As) is synthesized and their catalytic competency in the reduction of CO2 probed. Trends in both turnover numbers and frequencies are compared across this series, and [(iBu2Al)P7]2– found to be very high-performing and recyclable. Electronic structures across the series are compared using density functional theory to provide mechanistic insights. Despite being difficult to study, heterogenous pnictogens are an important category of catalytic materials for CO2 conversion as their high crustal abundance and low cost offers advantages in terms of sustainability. Here the authors report group 13 functionalized Zintl clusters as homogenous atom-precise models in hydroborative CO2 reduction. [ABSTRACT FROM AUTHOR]

Heteroleptic magnesium hydrides are important for their stoichiometric and catalytic reduction chemistry. Their primary nucleophilic site is typically the hydride, while the ancillary ligands commonly used are mostly spectators. Chemically non-innocent ligands in comparison are rarely applied on MgH as their reactivity can be complex. Milstein et al. have recently reported Mg-mediated alkyne hydrogenation by using their metal–ligand cooperation (MLC) concept on a dearomatized picolyl-based PNP pincer that is non-innocent with a nucleophilic nature. A '(PNP)MgH' is noted as the active catalyst in hydrogenation but without structural validation. Inspired by the same, we report herein a novel NNN-chelator (MesL) with a dearomatized picolyl moiety and its well-defined MgH. Having two prominent nucleophilic sites, the present MgH shows metal–ligand competition while reacting with certain electrophiles. It also distinguishes nonpolar alkynes and polar carbonyls by cleanly inserting itself into the former but not the latter. The nucleophilicities of the two sites are also probed by DFT methods and compared with Milstein's (PNP)MgH. Although the present system shows no MLC-type H2 activation, the addition of a CS2 molecule in that way is realized. [ABSTRACT FROM AUTHOR]

With the continuous expansion of industrial activities worldwide, industrial emissions of nitrogen oxides (NOx) pose a serious threat to both ecosystems and human health. Ammonia selective catalytic reduction of NO (NH3‐SCR) technology has emerged as the most effective means to reduce NOx emissions, and the development of catalysts is crucial for the successful implementation of this technology. In gas‐solid multiphase catalytic systems, the performance limitations of conventional catalysts can be effectively overcome by meticulously designing the nanostructures of the catalysts to achieve improved catalytic efficiency. In this review, the unique structural features of core‐shell structures, layered double hydroxide (LDHs), hollow nano spheres and nanotubes, along with their preparation processes, are systematically examined, beginning with the effects of structural changes on catalytic performance. Based on this review, the impact of structural modifications on the catalytic efficiency of the catalysts for the NH3‐SCR reaction and their anti‐poisoning performance were investigated. Ultimately, the influence of catalyst structural changes on the future design of catalysts is anticipated. This provides a robust scientific foundation for the conception of higher performance catalysts, paving the way for technological innovation and advancements in NOx emission reduction practices. [ABSTRACT FROM AUTHOR]

Commercial SSZ‐13 zeolite with different n(Si)/n(Al) ratios and from different suppliers were subjected to a post‐synthetic treatment in order to create mesopores of up to 15 nm. Furthermore, the materials were modified with copper ions and thoroughly physico‐chemically characterized. The modified textural properties varied the nature of copper species, and thus, activity in the selective catalytic reduction of NOx with ammonia (NH3‐SCR‐DeNOx). Pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) studies with hexane as probe liquid revealed improved intracrystalline diffusion for some Cu‐containing SSZ‐13 materials. The NH3‐SCR‐DeNOx pathways are verified via in situ DR UV‐Vis, in situ FT‐IR and EPR, temperature‐programmed studies as well as SSITKA studies that provide a mechanistic understanding of the reaction. Kinetic modelling results demonstrate the highest NH3‐SCR‐DeNOx reaction rates and up to 20 % lower energy barriers with n(Si)/n(Al) ratio of 6.5 for all modified forms (i. e., (NH4)Cu‐SSZ‐13_6.5 and Cu‐SSZ‐13_6.5_NaOH/0.1) and cause only negligible parasitic ammonia oxidation. The modelling of the stop‐flow experiments further demonstrates that the SCR pathway via the HONO surface intermediate is present but barely contributes to the overall NO conversion compared to the dominant path between adsorbed NH3 and NO from the gas phase. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of six novel triazole-based heteroscorpionate ligands based on heterocycle metathesis reactions and their iron(II) complexes. Single crystal structure analyses were performed, the spectroscopic and magnetic properties of the obtained complexes were studied and their spin crossover–structural relationships were compared to those obtained for their pyrazole-based analogues reported in the literature. In particular, the amino derivative complex bis[hydrobis(pyrazol-1-yl)(3-amino-1,2,4-triazol-1-yl)]iron(II) obtained by post-synthetic catalytic nitro-group reduction under pressure of hydrogen in an autoclave presents a scarce gradual spin crossover behavior at room temperature. The profile of the SCO curve can be explained by the presence of only relatively weak H bonds, spreading only in one dimension. Among the interesting spin transition behaviors observed for the different complexes, such stable, complete and gradual spin crossover at room temperature makes this neutral complex a good candidate for sublimation and future investigation as an active element notably for thermoreflectance-based surface microthermometry applications. [ABSTRACT FROM AUTHOR]

Homogeneous earth abundant transition-metal electrocatalysts capable of carbon dioxide (CO2) reduction to generate value-added chemical products are a possible strategy to minimize rising anthropogenic CO2 emissions. Previously, it was determined that Cr-centered bipyridine-based N2O2 complexes for CO2 reduction are kinetically limited by a proton-transfer step during C–OH bond cleavage. Therefore, it was hypothesized that the inclusion of pendent relay groups in the secondary coordination sphere of these molecular catalysts could increase their catalytic activity. Here, it is shown that the introduction of a pendent methoxy group favorably impacts a pre-equilibrium protonation prior to the catalytic resting state, resulting in a significant increase in catalytic activity without a loss of product selectivity for generating carbon monoxide (CO) from CO2. Interestingly, combining the pendent methoxy group with a cationic acid causes a positive shift of the catalytic reduction potential of the system, while maintaining increased activity and quantitative selectivity. This work suggests that tuning the secondary coordination sphere with respect to cationic proton sources can result in activity improvements by modifying the kinetic and thermodynamic aspects of proton transfer in the catalytic cycle. [ABSTRACT FROM AUTHOR]

The utilization of catalysts comprising metal nanoparticle has been beneficial for enhancing the performance of oxygen reduction reaction (ORR). However, the inadequate intrinsic activity of these catalysts still presents a significant challenge, limiting their overall effectiveness. This issue can be addressed by introducing single atoms, which can create a synergistic effect with the nanoparticles to catalyse and thereby improve performance. Nevertheless, the synergistic catalysis of nanoparticles and single atoms is still under investigation. In this study, we fabricated a core‐shell structured carbon framework incorporating Fe single atoms and Bi nanoparticles through the pyrolysis of COF and MOF core‐shell structures. Introducing Fe single atoms into ZIF‐8, with Fe‐ZIF‐8 as the core and Bi‐containing COF as the shell, resulted in higher ORR activity. The catalyst exhibited a half‐wave potential of 0.867 V and a high current density of 6.68 mA cm−2 in 0.1 M KOH, which were comparable to those of Pt/C equivalent. This study provides new research concepts for exploring the application of single atoms and nanoparticles in catalytic oxygen reduction reactions through synergistic effects. [ABSTRACT FROM AUTHOR]

Developing effective methods to enhance the photocatalytic hydrogen evolution activity of MoS 2 -based cocatalysts remains a challenge due to their inherently low activity. This study utilized a simultaneous vulcanization-nitrogenization solid-phase reduction method to prepare MoN 1.2x S 2-1.2x cocatalyst. The experimental and theoretical results indicate that the N-doped atoms triggered the H+ reduction catalytic activity on the (002) plane of the MoN 1.2x S 2-1.2x cocatalyst. Additionally, the MoN 1.2x S 2-1.2x cocatalyst significantly improves the hydrogen evolution reaction to form heterostructures with g-C 3 N 4 nanosheets (denoted as MoN 1.2x S 2-1.2x @g-C 3 N 4). Benefiting from the abundance of exposed catalytic sites and the excellent intrinsic charge separation characteristics of MoN 1.2x S 2-1.2x , an optimized MoN 1.2x S 2-1.2x @g-C 3 N 4 hybrid (5 wt%) exhibits an extraordinary photocatalytic H 2 evolution rate of 360.4 μmolg−1h−1, which is 19.6 and 14.3 folds higher than the g-C 3 N 4 and 5 wt% MoS 2 @g-C 3 N 4 , respectively. The simultaneous vulcanization-nitrogenization solid-phase reduction method offers a new and effective approach to dope N atoms in MoS 2 cocatalysts for photocatalytic applications. [Display omitted] • The doped N atoms triggered the catalytic activity on the (002) plane of MoS 2. • The MoN 1.2x S 2-1.2x reduces the charge transfer impedance at the interface. • The constructed heterostructure provides a transfer channel for carriers. • The 5 wt% MoN 1.2x S 2-1.2x @g-C 3 N 4 exhibits the HER of 360.4 μmolg−1h−1. [ABSTRACT FROM AUTHOR]

Efficient and low-cost nanocatalysts are extremely desirable for the catalytic reduction of 4-nitrophenol (4-NP). A smaller nanocatalyst particle size and stronger support effect can significantly enhance the catalytic performance. Naturally occurring halloysite nanotubes (HNTs) are promising alternative supports for fine metal nanoparticles, but the smooth surface and single type of functional groups on HNTs are usually unfavorable for the anchoring of metal ions. Herein, we modified HNTs using a mild and controllable molten salt etching method to create a rough surface (rHNTs), followed by loading Pt–Ni alloys to prepare Pt–Ni/rHNTs for the catalytic reduction of 4-NP. The results demonstrate that ultrafine Pt–Ni alloy nanoparticles with a diameter of 1.60 nm are uniformly dispersed on the rough surface of rHNTs. The particle size and catalytic performance can be tuned by adjusting the loading amount of Pt–Ni. The optimized Pt–Ni/rHNT (1 wt %) nanocatalyst reveals the smallest Pt–Ni particle size and the highest catalytic rate of 0.1953 min−1, which exceeds many Pt–Ni-based catalysts in previous reports. This work offers an ingenious idea for the mild surface modification of HNTs and a brilliant perspective for the rational design of inexpensive 4-NP reduction nanocatalysts. [ABSTRACT FROM AUTHOR]

The catalytic reduction of organic pollutants in water is a critical environmental challenge due to the persistent and hazardous nature of compounds like azo dyes and nitrophenols. In this study, we synthesized nanostructured CuO/TiO2 catalysts via a combustion technique, followed by calcination at 700 °C to achieve a rutile-phase TiO2 structure with varying copper loadings (5–40 wt.%). The catalysts were characterized using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR–FTIR) spectroscopy, thermogravimetric analysis-differential thermal analysis (TGA–DTA), UV-visible diffuse reflectance spectroscopy (DRS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS). The XRD results confirmed the presence of the crystalline rutile phase in the CuO/TiO2 catalysts, with additional peaks indicating successful copper oxide loading onto TiO2. The FTIR spectra confirmed the presence of all the functional groups in the prepared samples. SEM images revealed irregularly shaped copper oxide and agglomerated TiO2 particles. The DRS results revealed improved optical properties and a decreased bandgap with increased Cu content, and 4-Nitrophenol (4-NP) and methyl orange (MO), which were chosen for their carcinogenic, mutagenic, and nonbiodegradable properties, were used as model organic pollutants. Catalytic activities were tested by reducing 4-NP and MO with sodium borohydride (NaBH4) in the presence of a CuO/TiO2 catalyst. Following the in situ reduction of CuO/TiO2, Cu (NPs)/TiO2 was formed, achieving 98% reduction of 4-NP in 480 s and 98% reduction of MO in 420 s. The effects of the NaBH4 concentration and catalyst mass were investigated. The catalysts exhibited high stability over 10 reuse cycles, maintaining over 96% efficiency for MO and 94% efficiency for 4-NP. These findings demonstrate the potential of nanostructured CuO/TiO2 catalysts for environmental remediation through efficient catalytic reduction of organic pollutants. [ABSTRACT FROM AUTHOR]

Developing an efficient catalyst is the key to selective catalytic reduction (SCR) of NOx by CO (CO‐SCR) to simultaneously address the pollution of toxic NOx and CO. Herein, a novel Rh/TiO2/Ti monolithic catalyst is designed and synthesized, featuring Rh species in the form of single atoms (Rh1) and clusters (Rhn). This catalyst overcomes the inhibitory effects of oxygen, achieving low‐temperature NO conversion. The investigation substantively contributes insights into the strategic manipulation of active metal components, emphasizing the potential of single‐atom/cluster catalysts to enhance efficiency. The Rh/TiO2/Ti catalyst has demonstrated exceptional catalytic efficacy, achieving 100% NO conversion at a low temperature of 190 °C in the presence of oxygen. Additionally, it exhibits remarkable stability and water resistance for practical applications. Moreover, comprehensive characterization confirms that Rh clusters and single‐atom sites play an important role in the selective adsorption of NO and CO molecules, promoting the formation of –N2O species and ultimately resulting in the complete conversion of NO and CO to N2 and CO2. This study not only provides valuable guidance for designing high‐performance CO‐SCR catalysts but also underscores the potential of single atoms/clusters catalytic systems in both fundamental research and industrial catalysis. [ABSTRACT FROM AUTHOR]

A Fe modified MOF-derived MnOx catalyst has been synthesized and studied for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Compared with pure MnOx, Fe-modified MnOx showed a broader activity temperature window, enhanced N2 selectivity, and improved sulfur tolerance. On one hand, the incorporation of Fe into MnOx increased acidity, thereby facilitating the adsorption of NH3 as well as its activation, which plays a crucial role for the reduction of NOx. On the other hand, the presence of Fe resulted in decreased Mn4+, which contributes to improved N2 selectivity. Over Fe modified MnOx catalyst, the coordinated NH3, NH4+, bridging nitrate and bidentate nitrate are reactive, and participate in the NH3-SCR reaction following both "Eley–Rideal(E-R)" and "Langmuir–Hinshelwood(L–H)" mechanism. The present research provides an idea for broadening the activity temperature window and enhancing the sulfur tolerance of MnOx catalyst for the reduction of NOx, making it more suitable for practical application. [ABSTRACT FROM AUTHOR]

Mesoporous silicas of MCM-41 and MCM-48 types were synthesized and modified with copper by template ion-exchange (TIE) technique. A high dispersion of deposited copper species was managed by subsequent treatment of the samples with ammonia, urea, or acetonitrile solution. Copper-modified silicas were analysed in terms of their chemical composition (ICP-OES), ordering of porous structure (XRD), textural parameters (low-temperature N2 sorption), dispersion and form of introduced copper species (UV–vis-DR, XRD, H2-TPR, NH3-TPD). Mesoporous silicas modified with copper exhibited promising catalytic efficiency in selective catalytic reduction of NO with ammonia (NH3-SCR). The samples containing dispersed copper species (predominantly monomeric copper cations) presented enhanced catalytic activity compared to catalysts containing CuO aggregates. On the other hand, CuO aggregates showed greater catalytic activity in the side process of direct ammonia oxidation by oxygen present in the reaction mixture. It was demonstrated that TIE post-treatment of the samples with urea resulted in most effective improving dispersion of deposited copper and is less destructive for ordered porous structures of mesoporous silica comparing to treatment with ammonia solution. [ABSTRACT FROM AUTHOR]

The selective catalytic reduction (SCR) system plays a crucial role in reducing diesel exhaust emissions. To further enhance the performance of the SCR system, a three-dimensional numerical simulation model was established and experimentally validated for its reliability. Subsequently, the length (L1) and porosity (ε1) of carrier 1, as well as the length (L2) and porosity (ε2) of carrier 2, were varied to achieve an axial non-uniform distribution of the catalysts. The impact of this axial non-uniform distribution on the SCR system's performance was investigated. Finally, a fuzzy grey relational analysis method was employed to evaluate and optimize the influence of the aforementioned four individual parameters on the SCR system's denitrification (de-NOx) efficiency and pressure drop. The results indicate that variations of L1 have the greatest impact on de-NOx efficiency, while changes of ε2 have the most significant effect on pressure drop. The fuzzy grey relational degrees of L1, L2, ε1, and ε2 on de-NOx efficiency are 0.8267, 0.6288, 0.7457, and 0.8233, respectively. Similarly, the fuzzy grey relational degrees of L1, L2, ε1, and ε2 on pressure drop are 0.3552, 0.4894, 0.1045, and 0.7931, respectively. Compared with uniformly distributed catalysts, axially non-uniform distributed catalysts can improve de-NOx efficiency by 2.22% and reduce pressure drop by 46 Pa. This study provides theoretical and engineering references for improving the SCR catalyst coating process. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) has a crucial impact on the energy conversion efficiency and the performance of fuel cells, it is urgent to deliver low‐cost efficient ORR catalysts for the aim to scale up the utilization of fuel cells. In this study, three oxamidate copper(II) complexes [Cu2(trans‐L)(H2O)2(ClO4)2]·2H2O (Cuox), [Cu2(cis‐L)(bpy)(ClO4)2]·CH3OH (Cuoxbpy), and [Cu2(cis‐L)(mebpy)(ClO4)](ClO4) (Cuoxmebpy) (L = N,N–bis(2–pyridylmethyl)oxamide, bpy = 2,2′–bipyridine, and mebpy = 4,4′–dimethyl–2,2′–bipyridine) were prepared and characterized. The configuration of L varied from the trans form to the cis form as the bipyridines were introduced to the dicopper complex. The redox properties of three oxamidate copper(II) complexes and their catalytic activities for the ORR were studied in neutral aqueous solutions. The ORR onset potentials by Cuox, Cuoxbpy, and Cuoxmebpy were 0.417, 0.502, and 0.481 versus RHE, respectively. Three complexes homogeneously catalyzed the ORR to predominantly generate H2O2. A bimolecular catalytic pathway was proposed for the ORR mediated by Cuox, whereas a single‐molecular pathway was by Cuoxbpy and Cuoxmebpy. This work demonstrated that oxamidate metal complexes are promising ORR catalyst candidates provided that their electronic structures are appropriately tuned by altering the substituent on the organic ligands. [ABSTRACT FROM AUTHOR]

A novel TiO2/CoFe2O4/SiO2 magnetic nanocomposite was successfully synthesized using sol–gel and hydrothermal methods. This nanocomposite consists of highly dispersed CoFe2O4 and TiO2 nanoparticles on the surface of the SiO2 matrix. The synthesis process involved the utilization of activated carbon, which played a dual role as a support for depositing the CoFe2O4 and TiO2 nanoparticles and as a rigid pattern for producing the silica matrix that enmeshed the nanoparticles. To study the unique characteristics of the samples, a range of analytical techniques, such as FT‐IR, VSM, XRD, SEM, N2 adsorption–desorption analysis, BET and EDX were employed. We carried out a complete examination of the catalytic performance of the TiO2/CoFe2O4/SiO2 nanocomposite for the reduction of different substances, including methyl orange (MO), safranin O (SO), methylene blue (MB), rhodamine B (RhB), chromium (VI) ions, and nitroaromatic compounds such as 2‐nitrophenol (2‐NP), 4‐nitroaniline (4‐NA), 2‐nitroaniline (2‐NA), and 4‐nitrophenol (4‐NP). The findings of our study demonstrate the remarkable efficacy of the TiO2/CoFe2O4/SiO2 nanocomposite in efficiently reducing dyes, Cr (VI), and nitroaromatic compounds to their desired forms in environmentally friendly aqueous solutions. Notably, the nanocomposite stands out due to its simple synthesis process, effortless recyclability, and its convenient separation by a magnet. [ABSTRACT FROM AUTHOR]

The proper selection of a relevant mixer generally requires an effective assessment of several models against the application requirements. This is a complex task, as traditional evaluation methods generally focus only on a single aspect of performance, such as pressure loss, mixing characteristics, or heat transfer. This study assesses a urea-based selective catalytic reduction (SCR) system installed on a ship, where the installation space is limited and the distance between the urea aqueous solution injection position and the reactor is low; therefore, the static mixer installed in this pipeline has special performance requirements. In particular, four evaluation indices are used in this study: The B value, C value, pressure loss correction factor (Z′), and the ratio of the required distance to the equivalent diameter of the pipe (LV/D) when the velocity field after the mixer attains uniformity. Six types of static mixers were simulated with varying concentrations, flow speeds, and positions. A fuzzy comprehensive evaluation method was introduced to evaluate and compare the related advantages and disadvantages. The results showed that 1) mixing performance was related to the shape of the mixer and had no direct relationship with flow velocity. 2) For the same mixer position, the lower the urea concentration, the greater the difficulty of evenly mixing the solution. 3) At a constant urea concentration, the mixing performance improved when the mixer was closer to the injection inlet. 4) The installation of a GK mixer in the SCR system of a 9L20C diesel engine was best. [ABSTRACT FROM AUTHOR]

Catalytic conversion of water pollutants into environmentally benign products has emerged as a highly promising technique in the realm of environmental remediation. Among metal and metal oxide nanoparticles, copper/copper oxide nanoparticles serve as an ideal catalyst to reduce hazardous aquatic pollutants in order to protect the environment. In the present study, a simple chemical oxidation method was used for the synthesis of Cu(OH)2 nanowire, which was then annealed in argon atmosphere at different temperatures. On annealing, Cu(OH)2 gets transformed into oxide forms, CuO and/or Cu2O. The significance of the synthesized nanomaterial for the catalytic conversion of organic pollutants like para-nitrophenol (p-NP) and para-nitroaniline (p-NA), to para-aminophenol (p-AP) and para-phenylenediamine (p-PDA), respectively, in the presence of NaBH4 was studied and their catalytic activities were compared, and the rate constants were found to be 0.016 s−1 and 0.021 s−1 for p-NP and p-NA respectively. Due to the increased surface area, which improves charge carrier separation and adsorption, the CuO/Cu2O hybrid nanowires established excellent catalytic behavior for the conversion of these harmful pollutants into useful products within a few minutes. In addition to this, the heterojunction of CuO/Cu2O hybrid nanowires formed are effectively catalyze the "clock reaction," which is a periodic reversible switching of reactions between colorless leucomethylene blue and blue colored methylene blue. This property of the developed nanocomposite has been used in the visual colorimetric detection of Zn2+ions, with high limit of detection of 53 nM and high sensitivity. Morphology and surface analysis were obtained by X ray diffraction, Raman, and Scanning Electron Microscopic analysis and the reaction kinetics were studied by UV–visible spectroscopy. The recyclability of the synthesized catalyst was investigated over five cycles, and it maintained consistent performance, achieving 95% conversion efficiency for p-NP and 93% for p-NA after the five cycles. [ABSTRACT FROM AUTHOR]

Surface area, pore properties, synergistic behavior, homogenous dispersion, and interactions between carbon matrix and metal‐nanostructures are the key factors for achieving the better performance of carbon‐metal based (electro)catalysts. However, the traditional hydro‐ or solvothermal preparation of (electro)catalysts, particularly, bi‐ or tri‐metallic nanostructures anchored graphene (G) or carbon nanotubes (CNTs), often pose to poor metal–support interaction, low synergism, and patchy dispersion. At first, bimetallic flower‐like‐CuFeS2/NG and cube‐like‐NiFeS2/NCNTs nanocomposites were prepared by solvothermal method. The resultant bimetallic nanocomposites were employed to derive the 2D‐nano‐sandwiched Fe2CuNiS4/NGCNTs‐SW (electro)catalyst by a very simple and green urea‐mediated "mix‐heat" method. The desired physicochemical properties of Fe2CuNiS4/NGCNTs‐SW such as multiple active sites, strong metal‐support interaction, homogenous dispersion and enhanced surface area were confirmed by various microscopic and spectroscopic techniques. To the best of our knowledge, this is the first urea‐mediated "mix‐heat" method for preparing 2D‐nano‐sandwiched carbon‐metal‐based (electro)catalysts. The Fe2CuNiS4/NGCNTs‐SW was found to be highly effective for alkaline‐mediated oxygen evolution reaction at low onset potential of 284.24 mV, and the stable current density of 10 mA cm−2 in 1.0 m KOH for 10 h. Further, the Fe2CuNiS4/NGCNTs‐SW demonstrated excellent catalytic activity in the reduction of 4‐nitrophenol with good kapp value of 87.71 × 10−2 s−1 and excellent reusability over five cycles. Overall, the developed urea‐mediated "mix‐heat" method is highly efficient for the preparation of metal‐nanoarchitectures anchored 2D‐nano‐sandwiched (electro)catalysts with high synergism, uniform dispersion and excellent metal‐support interaction. [ABSTRACT FROM AUTHOR]

Developing an efficient catalyst is the key to selective catalytic reduction (SCR) of NOx by CO (CO‐SCR) to simultaneously address the pollution of toxic NOx and CO. Herein, a novel Rh/TiO2/Ti monolithic catalyst is designed and synthesized, featuring Rh species in the form of single atoms (Rh1) and clusters (Rhn). This catalyst overcomes the inhibitory effects of oxygen, achieving low‐temperature NO conversion. The investigation substantively contributes insights into the strategic manipulation of active metal components, emphasizing the potential of single‐atom/cluster catalysts to enhance efficiency. The Rh/TiO2/Ti catalyst has demonstrated exceptional catalytic efficacy, achieving 100% NO conversion at a low temperature of 190 °C in the presence of oxygen. Additionally, it exhibits remarkable stability and water resistance for practical applications. Moreover, comprehensive characterization confirms that Rh clusters and single‐atom sites play an important role in the selective adsorption of NO and CO molecules, promoting the formation of –N2O species and ultimately resulting in the complete conversion of NO and CO to N2 and CO2. This study not only provides valuable guidance for designing high‐performance CO‐SCR catalysts but also underscores the potential of single atoms/clusters catalytic systems in both fundamental research and industrial catalysis. [ABSTRACT FROM AUTHOR]

Furfural is an attractive bio‐based platform chemical that has many derivatives of commercial interest. Herein, we show that the selectivity of the direct furfural reduction can be steered from 2‐methylfuran and 2‐methyltetrahydrofuran to furfuryl alcohol and tetrahydrofurfuryl alcohol by varying the ratio of formic acid and sodium formate. These reagents take the role of terminal reductants in the disclosed heterogeneous Pd‐catalysed process. We report the development and optimisation of the reaction conditions for three different products directly from furfural: 2‐methyltetrahydrofuran, tetrahydrofurfuryl alcohol and 2‐methylfuran which were obtained in 59 %, 46 %, and 63 % selectivity, respectively. Furthermore, the protocol uses commercially available Pd/Al2O3 as catalyst and the formic acid and sodium formate can be obtained from biogenous sources. [ABSTRACT FROM AUTHOR]

The cube‐like copper ferrite (CuFe2O4) nanocrystallines are produced by the hydrothermal method without using any surfactant. X‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT‐IR) are used to characterize the morphology, structure, and phase of the samples. CuFe2O4 nanocubes show the superior catalytic performance of reduction 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP). 20 mg CuFe2O4 nanocubes can totally convert 4‐NP to 4‐AP in 30 s at room temperature. Moreover, the reaction kinetics of 4‐NP catalytic reduction are also studied. Hence, this innovative CuFe2O4 nanocube has a lot of potential for organic pollutant destruction. [ABSTRACT FROM AUTHOR]

The accurate and rapid detection of persulfate concentration is important for environmental decontamination and human health protection. In this work, a novel self-powered electrochemical sensor for the sensitive monitoring of persulfate was developed, which utilized cobalt tetroxide (Co3O4@CC) or tin-doped cobalt tetroxide (SnxCo3−xO4@CC) cathode as the sensing element and anode with electrogenic microorganisms as the power supplier. The Co3O4@CC and SnxCo3−xO4@CC electrodes were fabricated by in situ growing nanostructured Co3O4 or SnxCo3−xO4 catalysts on carbon cloth. Electrochemical tests revealed that these electrodes exhibited excellent catalytic reduction performance toward persulfate because of the synergistic catalysis by Co3O4 and electrode electrons, well-exposed Co2+/Co3+ catalytic sites, and high electron transfer efficiency. Tin doping could enhance the catalytic persulfate reduction by improving the conductivity and electron transfer of the Co3O4 catalyst. The electrode prepared at a hydrothermal temperature of 90 °C and a tin dosage of 0.286 g·cm−2 achieved the highest persulfate reduction activity under pH 7. The sensing properties of the self-powered sensors toward persulfate were explored in detail. Results showed that under the optimal external load of 300 Ω, the proposed sensor could display a broad detection range of 0 to 1500 μmol L−1 K2S2O8 with sensitivities of 1.13 and 0.12 μA μmol−1 L, a detection limit of 1.11 μmol L−1 (S/N = 3), and a fast response time within 30 s. The sensors also presented satisfactory reproducibility and selectivity during the detection of persulfate. The proposed sensor will provide a new approach for sensitive, on-site, and real-time monitoring of persulfate for a wide range of applications. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides with NH3 at low temperatures remains a crucial goal for industrial applications. However, effective catalysts operating at 70–90 °C are rarely reported, limiting SCR scenarios to high‐temperature conditions. Herein, we report a unique MnO2 nanofilament catalyst grown on activated semi‐coke synthesized via a one‐step in situ hydrothermal approach, which exhibits a stable and marked 100 % conversion rate of NO to N2 with 100 % selectivity at 90 °C, superior to the other prepared structures (nanowires, nanorods, and nanotubes). Temperature‐programmed desorption shows a large number of acid sites on MnO2(NFs)/ASC, benefiting the formation of NH4+ ions. Meanwhile, diffuse reflectance infrared Fourier transform spectroscopy reveals the activation of NO with O2 to form bidentate nitrate/bridging nitrate NO2 intermediates via bidentate nitrate species, triggering the Fast SCR with NH3 at low temperatures. Such an effective, easy‐to‐prepare, and low‐cost catalyst paves a new pathway for low‐temperature SCR for a wide range of application scenarios. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis. Here, we introduce the development of a visible‐light catalytic direct reduction coupling reaction between α‐CF3‐alkyl bromides and alkynyl bromides to access valuable organic frameworks. Our research confirms the excellent compatibility of this reaction with various functional groups, which could be used to modify the substrate with biologically active molecular fragments. Mechanistic investigations, including control experiments, fluorescence quenching studies, and light‐switching experiments, have provided insights into the reaction mechanism. This study paves the way for the application of visible‐light catalysis in diverse synthetic transformations, offering a sustainable and efficient approach to organic synthesis. [ABSTRACT FROM AUTHOR]

The development of Cu‐SSZ‐13 represents a significant breakthrough in the field of NOx removal from mobile exhaust, demonstrating excellent selective catalytic reduction (SCR) activity across a broad temperature range (200–500°C). However, the limited reactivity of Cu‐SSZ‐13 at temperatures below 200°C poses a challenge for the removal of NOx emitted during vehicle cold starts. To stimulate new efforts to enhance low‐temperature SCR performance, this review provides a fundamental understanding of the nature of Cu‐SSZ‐13 in catalyzing the SCR reaction. The structures, coordination environments, and oxidation states of Cu2+ during the SCR reaction, as well as the redox cycle pathway of Cu2+ ions and the characteristics of the rate‐determining step, were discussed. Based on these insights, several strategies for improving the low‐temperature activity of Cu‐SSZ‐13 are proposed. Finally, the review offers a perspective on the future of low‐temperature SCR of NOx over Cu‐SSZ‐13. [ABSTRACT FROM AUTHOR]

[Display omitted] The rational construction of highly active and robust non-precious metal oxygen reduction electrocatalysts is a vital factor to facilitate commercial applications of Zn-air batteries. In this study, a precise and stable heterostructure, comprised of a coupling of Co 3 Fe 7 and Fe 3 C, was constructed through an interface engineering-induced strategy. The coordination polymerization of the resin with the bimetallic components was meticulously regulated to control the interfacial characteristics of the heterostructure. The synergistic interfacial effects of the heterostructure successfully facilitated electron coupling and rapid charge transfer. Consequently, the optimized CST-FeCo displayed superb oxygen reduction catalytic activity with a positive half-wave potential of 0.855 V vs. RHE. Furthermore, the CST-FeCo air electrode of the liquid zinc-air battery revealed a large specific capacity of 805.6 mAh g Zn -1, corresponding to a remarkable peak power density of 162.7 mW cm−2, and a long charge/discharge cycle stability of 220 h, surpassing that of the commercial Pt/C catalyst. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis. Here, we introduce the development of a visible‐light catalytic direct reduction coupling reaction between α‐CF3‐alkyl bromides and alkynyl bromides to access valuable organic frameworks. Our research confirms the excellent compatibility of this reaction with various functional groups, which could be used to modify the substrate with biologically active molecular fragments. Mechanistic investigations, including control experiments, fluorescence quenching studies, and light‐switching experiments, have provided insights into the reaction mechanism. This study paves the way for the application of visible‐light catalysis in diverse synthetic transformations, offering a sustainable and efficient approach to organic synthesis. [ABSTRACT FROM AUTHOR]

The electrochemical proton reactivity of transition metal complexes receives significant attentions. A thorough understanding of proton-coupled electron transfer (PCET) pathways is essential for elucidating the mechanism behind a proton reduction reaction, and controlling the pathway is a key focus in the field of the catalyst development. Spin interactions within complexes, which arise during electron transfer, can affect significantly the PCET pathway. Herein, we explore the phenomenon of spin rearrangement during the electrochemical reorganization of high-spin cobalt complexes. Our findings reveal that opposing spin interactions, induced by different coordination environments, can alter the PCET pathway. Finally, detailed analysis of the PCET pathway allows us to propose mechanisms for proton reduction in high-spin cobalt complexes. Proton-coupled electron transfer (PCET) is an essential process of catalytic proton reduction and can be tuned by altering external or internal factors. Here, the authors control the exchange coupling types of Co complexes as model systems and demonstrate selective control of the PCET process. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NOx) are produced during the high‐temperature combustion process of fossil fuels, which are considered as an atmospheric pollutant that can lead to significant environmental issues such as acid rain and photochemical smog. Therefore, it is essential to minimize the concentration of NOx in the atmosphere in order to protect the ecological environment upon which human beings depends. The integrated utilization of NOx removal technology results in environmentally harmless compounds, such as N2 and H2O, through the processes like adsorption, separation, catalytic reduction and other methods. Metal‐organic frameworks (MOFs) are seen as ideal candidates for addressing NOx pollution issues in the atmosphere due to their high specific surface area, ultrahigh porosity and unlimited modifiability. Herein, the latest research progress in MOFs and MOFs‐derived materials related to NOx adsorption, separation and catalytic reduction is presented and summarized. Besides, some opportunities and problems need to be solved in this field are proposed and discussed. [ABSTRACT FROM AUTHOR]

We employ UV/Vis Diffuse Reflectance spectroscopy directly coupled with a packed bed flow reactor to extract quantitative kinetic information. We use as a show‐case the CuII/CuI redox dynamics during the reduction half cycle of the NH3‐Selective Catalytic Reduction (SCR) on Cu‐CHA catalysts. Our measurements enable quantification of the fraction of oxidized Cu, reconstructed by Multivariate Curve Resolution (MCR) together with monitoring of the gas‐phase evolution during the reaction. These data both on the dynamics of the gas‐phase and of the active site oxidation state have been used to assess the reduction half cycle rate equation and estimate the rate constant. Our results in terms of reaction orders and kinetic constant are in line with previous findings in the literature. Overall, our results demonstrate that the combined analysis of the UV spectra and of the gas‐phase dynamics provides converging and unparalleled kinetic insight: this approach effectively resolves ambiguities concerning RHC kinetics and mechanism. More in general, this work provides evidence that operando spectroscopy can be used to extract quantitative kinetic information on catalytic cycles. [ABSTRACT FROM AUTHOR]

For the development of Bi/Bi2O3@Al2O3 nanocomposites for wastewater treatment, corrosion resistance, and self-cleaning properties, it is imperative to carefully combine and analyze various elements for the optimization of catalyst performance. We aim to provide effective and long-term environmental remediation solutions. FTIR spectroscopy, XRD, SEM, EDS, TEM, UV-vis spectroscopy, PL, and TGA techniques were used to characterize the Bi/Bi2O3@Al2O3 nanocomposite. The nanocomposite displayed significant supercapacitance and self-cleaning properties. A composite of bismuth–aluminum oxides was used as a catalyst to facilitate the catalytic reduction of 4-nitrophenol (4-NP) dye in aqueous solutions, and excellent catalytic reduction results were obtained. The photocatalyst catalyzed the reduction of 4-NP to 99% with a rate constant of 2.592 × 10−2 (10−2 min−1) in a short period of 40 minutes under UV-visible irradiation. Photogenerated electrons migrate from Bi/Bi2O3@Al2O3 when exposed to visible light as a result of the significant band gap in the conduction band and the structure of the core electrostatic field within the p–n heterojunction. When exposed to visible light, the Bi/Bi2O3@Al2O3 nanocomposite exhibited more charge separation with excellent catalytic reduction efficiency. It represents an important development since it offers effective wastewater treatment remedies, energy storage, and self-cleaning properties. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a cover image and features several communications and papers on various topics such as supramolecular self-assembly, electrocatalysts for water splitting, and temperature sensing applications. The journal is published by The Royal Society of Chemistry, a leading chemistry community that reinvests its profits back into the chemistry community. [Extracted from the article]

Microporous zeolite is commonly employed as the catalyst for selective catalytic reduction of NOx using NH3 as reducing agent (NH3‐SCR) because of its strong acidity and exceptional hydrothermal stability. However, the channel of microporous zeolite limits mass transfer under low temperature. Hierarchical porous molecular sieves can overcome the above imperfections. Hierarchical pore (microporous/mesoporous/macroporous) ZSM‐5 molecular sieves were prepared using polystyrene(PS) microspheres with different particle size as the hard templates and then the ion exchange method was utilized to introduce the active components Ce, Cu, and La. In addition, the effect of PS microspheres with different size and H2O+SO2 on denitrification performance was also investigated. The results exhibited that the specific surface area of the hierarchical pore ZSM‐5 was the smallest when the size of polystyrene microspheres was the largest. The NOx conversion of all supported hierarchical porous catalysts is more than that of supported microporous ZSM‐5 catalyst in the low temperature (200 °C), which was because that the presence of the mesopores favored diffusion‐control in the low temperature, expediting the reactant transport. Furthermore, the supported hierarchical pore ZSM‐5 catalyst exhibited excellent denitrification performance in a wide temperature range of 250–500 °C (the conversion of NOx exceeded 80 % and the N2 selectivity was approaching 100 %). More importantly, the supported hierarchical pore ZSM‐5 catalyst demonstrated notably superior water and SO2 resistance in comparison to the supported micropore ZSM‐5 catalyst. [ABSTRACT FROM AUTHOR]

In this work, small-sized CaO–PdNps nanocomposites were synthesized using Lawsonia inermis leaf extract as a reducing and capping agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to analyze the produced nanocomposites. Based on these investigations, the average particle size was found to be 8±12nm, with a predominantly spherical morphology. The resulting nanocomposite was then tested for catalytic activity in methylene blue reduction. The mass of the catalyst and dye, the concentration of sodium borohydride ([NaBH4]), and the reaction time were all optimized using a central composite design (CCD). A significant correlation between predicted and experimental degradation percentages was shown by the CCD model (R2=0.9901), which also proved statistically significant (p-value=0.0016). Furthermore, a deep learning neural network (DLNN) was used to improve the prediction accuracy over and beyond CCD. There was a good connection between the two models as a result of using the CCD output as DLNN validation data. Mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), mean absolute percentage error (MAPE), and R2 were used to assess the performance of the DLNN. The results (MAE=0.001, MSE=0.01, RMSE=0.001, MAPE=0.001, R2=0.999) validated that all four metrics were successful in forecasting the percentage of degradation. [ABSTRACT FROM AUTHOR]

The reactivity of nitrogen oxide, NO, as a ligand in complexes with [Fe2-S2] and [Co2-S2] non-planar rhombic cores is examined by density functional theory (DFT). The cobalt-containing nitrosyl complexes are less stable than the iron complexes because the Co-S bonds in the [Co2-S2] core are weakened upon NO coordination. Various positions of NO were examined, including its binding to sulfur centers. The release of NO molecules can be monitored photochemically. The ability of NO to form a (NO)2 dimer provides a favorable route of electrochemical reduction, as protonation significantly stabilizes the dimeric species over the monomers. The quasilinear dimer ONNO, with trans-orientation of oxygen atoms, gains higher stability under protonation and reduction via proton–electron transfer. The first two reduction steps lead to an N2O intermediate, whose reduction is more energy demanding: in the two latter reaction steps the highest energy barrier for Co2S2(CO)6 is 109 kJ mol−1, and for Fe2S2(CO)6, it is 133 kJ mol−1. Again, the presence of favorable light absorption bands allows for a photochemical route to overcome these energy barriers. All elementary steps are exothermic, and the final products are molecular nitrogen and water. [ABSTRACT FROM AUTHOR]

Nanowire‐MnO2 and a series of Zr‐doped MnO2 catalysts with different Zr/Mn molar ratios were successively prepared by hydrothermal and impregnation methods. The Zr‐doped MnO2 catalyst with Zr/Mn molar ratio of 0.04 and calcination temperature of 400 °C, proved to be the optimal that possessed the highest low‐temperature denitration efficiency. It showed the NO conversion of ~92 % and N2 selectivity of ~80 % at 150 °C. Characterization results demonstrated that the main active phase of the catalyst was β‐MnO2, Zr atoms interacted with Mn atoms, and Zr doping increased the structural defects, oxygen vacancies and weak acid sites, which effectively enhanced the low‐temperature denitration activity and N2 selectivity of β‐MnO2, also improved the water and sulphur resistance to some extent. [ABSTRACT FROM AUTHOR]

Tetrapyrrolic containing metal complexes are among the most efficient molecular catalysts for the CO2 reduction. Metalloporphyrins and phthalocyanines are currently under investigations and their catalytic properties are among the best molecular catalysts. Corrole, a contracted tetrapyrrolic macrocycle has been also used to design molecular for the CO2 reduction. The electrochemical activity towards CO2 reduction can rival those of their porphyrin analogues. However, the catalytic activity of the metallocorrole is initiated at the corresponding MII/I couple. Accordingly, a catalytic current in presence of CO2 with cobalt corrole appears when the CoI species is generated. We have designed an electron deficient A2B corrole holding two −CF3 groups and a benzonitrile in the meso positions and its cobalt complex (1). We reasoned that these groups could shuffle the redox potentials to reach the M(I) oxidation states at more positive values thereby lowering the overpotential for the catalytic CO2 reduction. Our results clearly show that catalyst 1 when adsorbed on a carbon electrode, shows the most favourable catalytic performance for CO production, achieving an efficiency of 85 % with a current density of −1.5 mA cm−2 at −1.0 V vs NHE. The current densities of controlled potential electrolysis with increasing amount of KHCO3, were found to increase more than one order of magnitude with the formation of MeOH. [ABSTRACT FROM AUTHOR]

Cisplatin (CDDP) is an FDA‐approved chemotherapeutic drug used for treating various solid tumors. Despite of its effectiveness towards chemotherapy, it faces several challenges, such as multi‐drug resistance (MDR) and significant damage to the normal tissues. To address these challenges, various nanoformulations were developed to improve the delivery and safety of CDDP. One of the limitation in these CDDP loaded nanoformulations is that the effective CDDP loading concentrations are very poor. Therefore, this leaves a grand challenge to develop an effective strategy to carry higher concentrations of CDDP molecules, and also simultaneously exhibit very unique properties. Herein, we have developed an one‐pot synthesis of Cisplatin encapsulated Plasmonic blackbody (CiP), which offers a double play for near infrared (NIR) light activatable chemo‐photothermal therapy in destructing cancer cells as well as mediate catalytic reduction of 4‐nitrophenol (4‐NP). The CiP nanoformulation exhibits superior light absorbing capabilities in the NIR region with an appreciable photothermal conversion efficiency of 41 %. Further, NIR light activatable combinatorial therapeutic approach of CiP was demonstrated against ovarian cancer cells and as a catalyst for the reduction of model pollutant 4‐nitrophenol. Our findings highlight the potential of CiP as a versatile platform for light‐activated combinatorial cancer therapy and environmental pollutant remediation. [ABSTRACT FROM AUTHOR]

Transition metal-based mixed metal oxides (MMOs) are nexus nanomaterials that garner significant interest from scientists because of their unique magnetic, electronic, optical and catalytic properties that can easily be tailored by varying their composition and structure. Although MMOs hold significant potential in multifunctional applications, but they are plagued by certain challenges such as identifying the appropriate method for synthesis, complications in controlling the surface area and the oxidation states of the constituent transition metals, while also ensuring the homogenous distribution of the constituent metal ions. Therefore, the present work aims to study the formation of homogenous and porous zinc-copper-nickel mixed metal oxide (ZnCuNi-MMO) by performing calcination of ZnCuNi-LDH at 350 °C. The obtained ZnCuNi-MMO was characterized using PXRD, SEM–EDX and BET techniques. Thereafter, ZnCuNi-MMO was applied as a heterogeneous catalyst for the hydrogenation of p-nitroaniline (p-NA) and catalytic reduction of methyl orange (MO) dye. The pollutant degradation characteristics were assessed using time-dependent UV–Visible absorption spectroscopy showing advanced efficient behavior of ZnCuNi-MMO towards the hydrogenation of p-NA (96.98%) and reduction of MO (95.58%). The catalyst exhibited fast reaction rates (0.402 min−1 for hydrogenation of p-NA and 0.471 min−1 for catalytic reduction of MO) and kinetics analysis of the experimental data was found to be coherent with the pseudo-first order model, thereby implying that the catalysis proceeded through the Langmuir–Hinshelwood mechanism. Thus the obtained experimental results highlight the utility and viability of synthesized MMO as an efficacious and sustainable catalytic material. [ABSTRACT FROM AUTHOR]

When platinum-containing diesel oxidation catalysts (DOC) are exposed to high temperatures under lean conditions, the platinum nanoparticles form volatile platinum dioxide on the catalyst surface. The exhaust flow carries the volatile platinum dioxide to the downstream aftertreatment catalyst, such as the selective catalytic reduction (SCR) catalyst, that is responsible for reducing the nitrogen oxides (NOx) emissions and can negatively impact its performance, by promoting the parasitic oxidation of ammonia. Here we investigate the factors such as exposure time, temperature and DOC design characteristics for their impact on the platinum dioxide migration, by characterising the amount of platinum deposited on the SCR catalyst at very low levels (<5 ppm), using inductively coupled plasma optical emission spectroscopy (ICP-OES) fire assay technique. Our results indicate that welldispersed platinum, not associated with palladium, is most prone to platinum dioxide migration. We also compare several methods to suppress the platinum dioxide migration from the DOC, such as sintering of the platinum nanoparticles, stabilising the platinum nanoparticles via interaction with palladium or covering the platinum nanoparticles with a high surface area capture layer to trap the volatile platinum dioxide. [ABSTRACT FROM AUTHOR]

The development of catalysts composed of single atoms is crucial for enhancing the performance of oxygen reduction reaction (ORR). However, the unsatisfactory intrinsic activity of these catalysts still poses a major challenge, limiting their overall effectiveness. One approach to addressing this challenge is the introduction of metal clusters, which can form a synergistic effect with the single atoms, ultimately improving their performance. In this study, core‐shell structured carbon polymer is constructed with Zn atoms and Sn nanoclusters by directly subjecting pyrolysis of the covalent organic polymer (COP) and metal organic framework (MOF) (COP@MOF). The thin COP shell serves a dual purpose: it prevents the collapse and aggregation of zeolitic imidazolate framework‐8 (ZIF‐8) and promotes the formation of mesopores, facilitating mass transport and enhancing the graphitization degree to improve conductivity. The resulting Sn‐COP@MOF800 exhibits promising catalytic performance in the ORR, demonstrating a half‐wave potential of 0.81 V and current density of 5.56 mA cm−2 in 0.1 m KOH, which is comparable to that of Pt/C. This study provides new ideas for exploring the application of metal single atoms and metal nanoclusters in ORR catalysis through synergistic effects. [ABSTRACT FROM AUTHOR]

A novel La/O co‐doped SnS oxysulfide catalyst (labeled SnLaOS) with heterovalent tin states and sulfur vacancy defects is successfully synthesized for effective catalytic reduction of toxic organics heavy metal ions with NaBH4 in the dark. La/O co‐doped and hydrogen peroxide‐driven SnLaOS catalyst with suitable heterovalent Sn2+/Sn4+ states and sulfur vacancy defects exhibited excellent catalytic reduction capability. The 100 mL 20 ppm of 4‐nitrophenol (4‐NP) and 50 ppm of rhodamine‐B (RhB), methylene blue (MB), methyl orange (MO), and Cr(VI) solution are entirely reduced by 5 mg SnLaOS‐3 within 10, 12, 12, 16, and 14 min, respectively, with durable stability. Synergistic transition metal La3+‐cation and O2−‐anion co‐doped SnS adjusted the energy bandgap and introduced sulfur vacancy defects, and the hydrogen peroxide‐driven regulated the SnLaOS with suitable Sn4+/Sn2+ states ratio. The sulfur vacancies in SnLaOS provide active sites for adsorbed proton for pollutants reduction, and heterovalent Sn2+/Sn4+ states in SnLaOS facilitates electrons efficient transfer through electron hopping between Sn2+ and Sn4+ for pollutants reduction. This study provides a novel efficient catalyst for the water pollutants treatment. [ABSTRACT FROM AUTHOR]