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We develop a semi-analytical model for transport in structured catalytic microreactors, where both reactant and product are compressible fluids. Using lubrication and Fick–Jacobs approximations, we reduce the three-dimensional governing equations to an effective one-dimensional set of equations. Our model captures the effect of compressibility, corrugations in the shape of the reactor, and an inhomogeneous catalytic coating of the reactor walls. We show that in the weakly compressible limit (e.g., liquid-phase reactors), the distribution of catalyst does not influence the reactor yield, which we verify experimentally. Beyond this limit, we show that introducing inhomogeneities in the catalytic coating and corrugations to the reactor walls can improve the yield. [ABSTRACT FROM AUTHOR]

We combine ab initio molecular dynamics (AIMD) simulations with an unsupervised machine learning approach to automate the search for possible configurations of CO oxidation reaction intermediates catalyzed by the atomically dispersed Pt1/TiO2 catalyst. Following the example of Roncoroni and co-workers [Phys. Chem. Chem. Phys. 25, 13741 (2023)], we employ t-distributed stochastic neighbor embedding and hierarchical density-based spatial clustering of applications with noise to reduce the dimensionality and cluster AIMD snapshots based on the local coordination environment of Pt. We identify new local minima, particularly in cases where CO2 is bound to the active site, because it can coordinate in various ways with both the metal and support. The new minima constitute additional elementary steps in some proposed pathways for CO oxidation, resulting in turnover frequencies that differ from prior estimates by several orders of magnitude. This work, therefore, demonstrates that configuration sampling is a necessary component of computational studies of catalytic cycles for atomically dispersed catalysts. [ABSTRACT FROM AUTHOR]

We combine ab initio molecular dynamics (AIMD) simulations with an unsupervised machine learning approach to automate the search for possible configurations of CO oxidation reaction intermediates catalyzed by the atomically dispersed Pt1/TiO2 catalyst. Following the example of Roncoroni and co-workers [Phys. Chem. Chem. Phys. 25, 13741 (2023)], we employ t-distributed stochastic neighbor embedding and hierarchical density-based spatial clustering of applications with noise to reduce the dimensionality and cluster AIMD snapshots based on the local coordination environment of Pt. We identify new local minima, particularly in cases where CO2 is bound to the active site, because it can coordinate in various ways with both the metal and support. The new minima constitute additional elementary steps in some proposed pathways for CO oxidation, resulting in turnover frequencies that differ from prior estimates by several orders of magnitude. This work, therefore, demonstrates that configuration sampling is a necessary component of computational studies of catalytic cycles for atomically dispersed catalysts. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (CO2RR) for CH4 production presents a promising strategy to address carbon neutrality, and the incorporation of a second metal has been proven effective in enhancing catalyst performance. Nevertheless, there remains limited comprehension regarding the fundamental factors responsible for the improved performance. Herein, the critical role of Pd in electrocatalytic CO2 reduction to CH4 on Cu-based catalysts has been revealed at a molecular level using in situ surface-enhanced Raman spectroscopy (SERS). A "borrowing" SERS strategy has been developed by depositing Cu–Pd overlayers on plasmonic Au nanoparticles to achieve the in situ monitoring of the dynamic change of the intermediate during CO2RR. Electrochemical tests demonstrate that Pd incorporation significantly enhances selectivity toward CH4 production, and the Faradaic efficiency (FE) of CH4 is more than two times higher than that for the catalysts without Pd. The key intermediates, including *CO2−, *CO, and *OH, have been directly identified under CO2RR conditions, and their evolution with the electrochemical environments has been determined. It is found that Pd incorporation promotes the activation of both CO2 and H2O molecules and accelerates the formation of abundant active *CO and hydrogen species, thus enhancing the CH4 selectivity. This work offers fundamental insights into the understanding of the molecular mechanism of CO2RR and opens up possibilities for designing more efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

To tackle the challenge of ground-level ozone pollution, this study proposed a potential catalytic design approach for ozone decomposition using Cu–Mn bimetallic oxide. This approach is grounded in an understanding of the intrinsic reactivity for catalyst and incorporates a novel potassium-driven low-temperature oxidation process for catalyst synthesis. The research highlights the creation of a highly reactive Cu–Mn oxide phase with extensive defect coverage, leading to significantly increased reaction rates. It also identifies the MnO2(100) facet as a crucial active phase, where oxygen vacancies simultaneously enhance O3 adsorption and decomposition, albeit with a concurrent risk of O2 poisoning due to the stabilization of adsorbed O2. Crucially, the incorporation of Cu offsets the effects of oxygen vacancies, influencing conversion rates and lessening O2 poisoning. The synergistic interplay between Cu and oxygen vacancies elevates the performance of the defect-rich Cu–Mn oxide catalyst. By combining computational and experimental methods, this study not only advances the understanding of the Cu–Mn oxide system for ozone decomposition but also contributes valuable insights into developing more efficient catalysts to mitigate ozone pollution. [ABSTRACT FROM AUTHOR]

Substituting slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is considered as one of the feasible strategies for achieving energy-saving hydrogen production. Herein, a uniform layer of NiMoO4 nanorods was grown on nickel foam by a hydrothermal method. Then, a series of Ni-MoOx/NF-X nanorod catalysts comprising Ni/NiO and MoOx (MoO2/MoO3) were prepared through regulating annealing atmosphere and reduction temperature. The optimized Ni-MoOx/NF-3 with a large accessible specific area can act as a bifunctional catalyst for electrocatalytic anodic UOR and cathodic hydrogen evolution reaction (HER). At a current density of 100 mA cm−2, the introduction of urea can significantly reduce the overpotential of Ni-MoOx/NF-3 by 210 mV compared to OER. In addition, Ni-MoOx/NF-3 has a higher intrinsic activity than other catalysts. It only requires −0.21 and 1.38 V to reach 100 mA cm−2 in HER and UOR, respectively. Such an excellent performance can be attributed to the synergistic function between Ni and MoOx. The presence of metallic Ni and reduced MoOx in pairs is beneficial for improving the electrical conductivity and modulating the electronic structure, resulting in enhancing the electrocatalytic performance. When assembling Ni-MoOx/NF-3 into an overall urea–water splitting system, it can achieve energy-saving hydrogen production and effective removal of urea-rich wastewater. [ABSTRACT FROM AUTHOR]

Adsorbed molecules on a catalyst almost always arrange themselves in a manner that is far from perfectly random, which gives rise to spatial correlations. These correlations are a result of the interactions between the adsorbed species (adspecies) as well as elementary processes such as diffusion and reaction events that shape the adspecies arrangements. Despite their importance, spatial correlations are usually ignored while writing species balance equations for the modeling of heterogeneous catalytic systems. Recently, we have introduced a probabilistic microkinetic modeling (p-MKM) framework that aims at incorporating spatial correlations in the form of a short-ranged order (SRO) parameter into species balance equations. Here, we extend the approach to catalytic systems of higher complexity, namely, longer interactions and multiple species. This is made possible by including multiple pair probabilities in the p-MKM model for the first time. The interplay between different SRO parameters is probed. An important consideration is how many pair probabilities should be included to capture the underlying complexity with sufficient accuracy. [ABSTRACT FROM AUTHOR]

We investigate the formation and transport of gas bubbles across a model porous electrode/catalyst using lattice Boltzmann simulations. This approach enables us to systematically examine the influence of a wide range of morphologies, flow velocities, and reaction rates on the efficiency of gas production. By exploring these parameters, we identify critical parameter combinations that significantly contribute to an enhanced yield of gas output. Our simulations reveal the existence of an optimal pore geometry for which the product output is maximized. Intriguingly, we also observe that lower flow velocities improve gas production by leveraging coalescence-induced bubble detachment from the electrode/catalyst. [ABSTRACT FROM AUTHOR]

Electrocatalytically reducing CO2 into value-added products is a challenging but promising process. Catalysts have been proposed to reduce the potential necessary for the reaction to occur, among which single-atom alloys (SAAs) are particularly promising. Here, we employ density functional theory calculations and the computational electrode model to predict whether silver-based SAAs have the potential to be effective electrocatalysts to convert CO2 into C1 products. We take into account surface defects by using the Ag(211) surface as a model. We also verify whether the proposed materials are prone to OH poisoning or enhance the competing hydrogen evolution reaction. Our calculations predict that these materials show weak mixing between the host and the dopant, characterized by a sharp peak in the density of states near the Fermi energy, except when copper (also a coinage metal) is used as the dopant. This affects the adsorption energy of the different intermediate molecules, yielding different reaction profiles for each substrate. As non-doped silver, copper-doped SAA tends to spontaneously desorb carbon monoxide (CO) instead of proceeding with its reduction. Other elements of the fourth period (Fe, Co, and Ni) tend to bind to the CO molecule but do not favor more reduced products. These metals also tend to enhance the hydrogen evolution reaction. On the contrary, we show that the Ir and Rh dopants have significant potential as electrocatalysts, which favors the reduction of CO over its desorption while also suppressing the hydrogen evolution reaction at potentials lower than those required by copper. They have also been shown to not be prone to poisoning by OH radicals. [ABSTRACT FROM AUTHOR]

Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2. [ABSTRACT FROM AUTHOR]

Photoredox properties of several earth-abundant light-harvesting transition metal complexes in combination with cobalt-based proton reduction catalysts have been investigated computationally to assess the fundamental viability of different photocatalytic systems of current experimental interest. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations using several GGA (BP86, BLYP), hybrid-GGA (B3LYP, B3LYP*), hybrid meta-GGA (M06, TPSSh), and range-separated hybrid (ωB97X, CAM-B3LYP) functionals were used to calculate relevant ground and excited state reduction potentials for photosensitizers, catalysts, and sacrificial electron donors. Linear energy correction factors for the DFT/TD-DFT results that provide the best agreement with available experimental reference results were determined in order to provide more accurate predictions. Among the selection of functionals, the B3LYP* and TPSSh sets of correction parameters were determined to give the best redox potentials and excited states energies, ΔEexc, with errors of ∼0.2 eV. Linear corrections for both reduction and oxidation processes significantly improve the predictions for all the redox pairs. In particular, for TPSSh and B3LYP*, the calculated errors decrease by more than 0.5 V against experimental values for catalyst reduction potentials, photosensitizer oxidation potentials, and electron donor oxidation potentials. Energy-corrected TPSSh results were finally used to predict the energetics of complete photocatalytic cycles for the light-driven activation of selected proton reduction cobalt catalysts. These predictions demonstrate the broader usefulness of the adopted approach to systematically predict full photocycle behavior for first-row transition metal photosensitizer–catalyst combinations more broadly. [ABSTRACT FROM AUTHOR]

According to the classic theory of nucleation around a charged particle, dipoles induced in the particle's neighbors by the charged nucleation center decrease the electric field around it. This reduces the system's Gibbs energy and thus increases the nucleation rate. Unlike the situation of a neutral gas and an already existing charged particle, in plasma, charging the center of nucleation is the result of the separation of charges (a negatively charged center and a positively charged surrounding). This process being similar to charging of a capacitor, it demands extra energy, and thus increases the Gibbs energy. As a result, the nucleation rate decreases in comparison with the nucleation rate in a neutral medium. In this work, the process of nucleation in a plasma is considered and the nucleation rate is calculated. It is shown that for the conditions typical for arcs used for the production of nanoparticles, the reduction in the nucleation rate is an order of magnitude or higher. [ABSTRACT FROM AUTHOR]

Electrochemical and photochemical hydrogen (H2) evolution activities of a 6-fluoro-2-hydroxypyridinate (fhp−)-bridged paddlewheel-type dirhodium (Rh2) complex, [Rh2(fhp)4], were investigated through experimental and theoretical approaches. In DMF, the [Rh2(fhp)4] underwent a one-electron reduction (assigned to Rh24+/3+) at −1.31 V vs SCE in the cathodic region. Adding trifluoroacetic acid as a proton source to the electrochemical cell containing [Rh2(fhp)4], the significant catalytic current, i.e., electrochemical H2 evolution, was observed; the turnover frequency and overpotential of electrochemical H2 evolution were 18 244 s−1 and 732 mV, respectively. The reaction mechanism of electrochemical H2 evolution catalyzed by [Rh2(fhp)4] in DMF was examined in detail by theoretically predicting the redox potentials and pKa values of the reaction intermediates using density functional theory calculations. The calculations revealed that (i) the formation of a one-electron reduced species, [Rh2(fhp)4]−, triggered for H2 evolution and (ii) the protonation and reduction processes of [Rh2(fhp)4]− to further reduced hydride intermediates proceeded directly via a concerted proton–electron transfer mechanism. Moreover, [Rh2(fhp)4] was shown to be a highly efficient H2 evolution catalyst (HEC) for photochemical proton reduction reactions when combined with an artificial photosynthetic (AP) system containing [Ir(ppy)2(dtbbpy)]PF6 and triethylamine, which served as a photosensitizer and a sacrificial electron donor, respectively. Under visible light irradiation, the total amount of H2 evolved and its turnover number (per Rh ion) were 1361.0 µmol and 13 610, respectively, which are superior to those of previously reported AP systems with rhodium complexes as HEC. [ABSTRACT FROM AUTHOR]

Double-atom catalysts (DACs) for harmful nitrate (NO3−) electroreduction to valuable ammonia (eNO3RR) is attractive for both environmental remediation and energy transformation. However, the limited metal loading in most DACs largely hinders their applications in practical catalytic applications. Therefore, exploring ultrahigh-density (UHD) DACs with abundant active metal centers and excellent eNO3RR activity is highly desired under the site-distance effect. Herein, starting from the experimental M2N6 motif deposited on graphene, we firstly screened the low-density (LD) Mn2N6 and Fe2N6 DACs with high eNO3RR activity and then established an appropriate activity descriptor for the LD–DAC system. By utilizing this descriptor, the corresponding Mn2N6 and Fe2N6 UHD–DACs with dynamic, thermal, thermodynamic, and electrochemical stabilities, are identified to locate at the peak of activity volcano, exhibiting rather-low limiting potentials of −0.25 and −0.38 V, respectively. Further analysis in term of spin state and orbital interaction, confirms that the electronic state effect similar to that of LD–DACs enable the excellent eNO3RR activity to be maintained in the UHD–DACs. These findings highlight the promising application of Mn2N6 and Fe2N6 UHD–DACs in nitrate electroreduction for NH3 production and provide impetus for further experimental exploration of ultrahigh-density DACs based on their intrinsic electronic states. [ABSTRACT FROM AUTHOR]

Surface property modification of catalyst support is a straightforward approach to optimize the performance of supported noble metal catalysts. In particular, oxygen vacancies and hydroxyl groups play significant roles in promoting noble metal dispersion on catalysts as well as catalytic stability. In this study, we developed a nanoflower-like TiO2-supported Pd catalyst that has a higher concentration of oxygen vacancies and surface hydroxyl groups compared to that of commercial anatase and P25 support. Notably, due to the distinctive structure of the nanoflower-like TiO2, our catalyst exhibited improved dispersion and stabilization of Pd species and the formation of abundant reactive oxygen species, thereby facilitating the activation of CO and O2 molecules. As a result, the catalyst showed remarkable efficiency in catalyzing the low-temperature CO oxidation reaction with a complete CO conversion at 80 °C and stability for over 100 h. [ABSTRACT FROM AUTHOR]

The interaction between adjacent active sites is crucial to balance the efficiency and utilization of functional atoms in single-atom catalysts. Herein, the catalytic activity of hydrogen evolution reaction at different site (nitrogen coordinated transition metal centers embedded in graphene) distances was comprehensively investigated by density functional theory calculations. The results show that a proximity effect of reactivity and site spacing can be identified in the Co-series single-atom catalysts. Although the proximity effect is more linearly responded with the site spacing along x direction, an optimal distance of ∼0.8 and ∼2.8 nm are found for Co and Rh, Ir atoms, respectively. An in-depth analysis of the electronic property reveals that the proximity effect is caused by the distinct net charge of the active site, which is affected by the d z 2 position relative to EF. Subsequently, an excess electron nodal channel in x direction was found to serve as a communication pathway between the active sites. Through the finding in this work, an optimal Fe-N2C2 structure was deliberately designed and has shown prominent proximity effect as Co-series do. The results reported in this work provide a simple and effective tuning method for the reactivity of a single-atom catalyst. [ABSTRACT FROM AUTHOR]

In this work, we have proposed a Continuous Constant Potential Model (CCPM) based on grand canonical density functional theory for describing the electrocatalytic thermodynamics on single atom electrocatalysts dispersed on graphene support. The linearly potential-dependent capacitance is introduced to account for the net charge variation of the electrode surface and to evaluate the free energetics. We have chosen the CO2 electro-reduction reaction on single-copper atom catalysts, dispersed by nitrogen-doped graphene [CuNX@Gra (X = 2, 4)], as an example to show how our model can predict the potential-dependent free energetics. We have demonstrated that the net charges of both catalyst models are quadratically correlated with the applied potentials and, thus, the quantum capacitance is linearly dependent on the applied potentials, which allows us to continuously quantify the potential effect on the free energetics during the carbon dioxide reduction reaction instead of confining it to a specific potential. On the CuN4@Gra model, it is suggested that CO2 adsorption, coupled with an electron transfer, is a potential determining step that is energetically unfavorable even under high overpotentials. Interestingly, the hydrogen adsorption on CuN4@Gra is extremely easy to occur at both the Cu and N sites, which probably results in the reconstruction of the CuN4@Gra catalyst, as reported by many experimental observations. On CuN2@Gra, the CO2RR is found to exhibit a higher activity at the adjacent C site, and the potential determining step is shifted to the *CO formation step at a wide potential range. In general, CCPM provides a simple method for studying the free energetics for the electrocatalytic reactions under constant potential. [ABSTRACT FROM AUTHOR]

The development of highly active and stable iron–nitrogen (Fe–Nx) based oxygen reduction reaction (ORR) catalysts with pH versatility is one of the future directions of electrochemical energy. However, the task of designing and controlling the three-dimensional local structure of Fe species to obtain high ORR activity and stability remains a challenge. In this study, we prepared hierarchical porous FeN–hcC (iron–nitrogen–highly curved carbon) catalysts derived from ZIF-L by a soft template method. The highly curved carbon surface possibly results in a compressive strain effect on the supported Fe–Nx active site, which can not only enhance the high exposure of the active site to improve the electrocatalytic activity, but also facilitate the stability of the Fe–Nx site during the ORR catalytic process. FeN–hcC-1 exhibited a high half-wave potential of 0.89, 0.77 and 0.82 V vs. RHE in alkaline, acidic, and neutral media, respectively. In addition, after cyclic durability tests in different electrolyte environments, good stability is still maintained, which is significantly better than the planar Fe–Nx site and Pt/C catalyst. This work provides a new synthetic strategy for the construction of highly curved surfaces of carbon materials, while inspiring a method to improve the ORR performance of ZIF-derived materials. [ABSTRACT FROM AUTHOR]

We present a universal preparation method for synthesizing a range of pure-phase IB-group Sn-based alloy catalysts (Cu3Sn, Ag4Sn, and AuSn) for electrochemical reduction of CO2 to C1 product. The selectivity can be widely adjusted by altering metal composition and potential, improving the understanding of the structure–activity relationship in various Sn-based alloys. [ABSTRACT FROM AUTHOR]

Sulfonated hierarchical H-ZSM-5 monoliths were synthesized via ice-templating as solid acid catalysts for biodiesel production. Characterization confirmed successful –SO3 group grafting, increasing acid density. The catalysts achieved over 90% conversion of oleic acid in esterification, with easy recovery and reuse, and the relationship between porosity and acid density was explored. [ABSTRACT FROM AUTHOR]

Here, we propose a sub-3 nm small-size PtCo alloy catalyst integrated into a porous nitrogen-doped nanosheet through a space-confined and interfacial induction strategy. The designed PtCo–CoNC–P catalyst exhibits exceptional durability, with only a minimal 2 mV decline in half-wave potential after 30 000 cycles of accelerated durability tests. [ABSTRACT FROM AUTHOR]

A systematic investigation into the factors which influence catalytic activity in 50 simple (mostly) quaternary ammonium- and phosphonium halide catalysts for the hydrolysis of poly(ethylene terephthalate) has revealed the most efficacious constitutional isomer class and the optimum properties these catalysts should possess. General guidelines for catalyst design are provided. [ABSTRACT FROM AUTHOR]

An efficient hydrogen evolution reaction catalyst of ultrafine Pt nanoparticles loaded onto N-doped CoO was synthesized. This catalyst displayed high electrocatalytic activity and stability. The outstanding performance is attributed to the interactions between the active sites and support, as well as the regulation of the electronic structure through covalent nitrogen bridging. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction to ammonia (ENRA) in acidic media is currently a challenge. Herein, we presented a CoFe2O4/GO catalyst that exhibited a high faradaic efficiency (95.51%) and ammonia yield rate (1268.04 μmol h−1 cm−2) for ENRA under acidic conditions. The ENRA reaction mechanism was investigated through in situ ATR-FTIR spectroscopy and isotope labeling experiments. [ABSTRACT FROM AUTHOR]

Photo-thermo catalysis that combines photo- and thermo-catalysis has emerged as an attractive approach for effective and economical elimination of pollutants. Herein, we fabricated a robust, highly water stable 2D Co(II)-MOF photo-thermo catalyst towards the decomposition of permanganate anions. It has been demonstrated that Co(II)-MOF exhibits excellent catalytic capacity, good selectivity and incredible reusability for degrading MnO4-. The reaction rate of the process was investigated for thermo-photo vs. thermo/photo processes to provide conclusive evidence that Co(II)-MOF shows a strong synergistic use as both an energy source and Lewis acid. [ABSTRACT FROM AUTHOR]

It is well‐established that Pt‐based catalysts suffer from the unfavorable linear scaling relationship (LSR) between *OOH and *OH (ΔG(*OOH)=ΔG(*OH)+3.2±0.2 eV) for the oxygen reduction reaction (ORR), resulting in a great challenge to significantly reduced ORR overpotentials. Herein, we propose a universal and feasible strategy of fluorine‐doped carbon supports, which optimize interfacial microenvironment of Pt‐based catalysts and thus significantly enhance their reactive kinetics. The introduction of C−F bonds not only weakens the *OH binding energy, but also stabilizes the *OOH intermediate, resulting in a break of LSR. Furthermore, fluorine‐doped carbon constructs a local super‐hydrophobic interface that facilitates the diffusion of H2O and the mass transfer of O2. Electrochemical tests show that the F‐doped carbon‐supported Pt catalysts exhibit over 2‐fold higher mass activities than those without F modification. More importantly, those catalysts also demonstrate excellent stability in both rotating disk electrode (RDE) and membrane electrode assembly (MEA) tests. This study not only validates the feasibility of tuning the electrocatalytic microenvironment to improve mass transport and to break the scaling relationship, but also provides a universal catalyst design paradigm for other gas‐involving electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

The Kirsanov reaction has been used to synthesise air stable, efficient and selective bifunctional aminophosphonium catalysts for the alternating ring-opening copolymerisation of cyclohexene oxide and phthalic anhydride without the need for a co-initiator. [ABSTRACT FROM AUTHOR]

The copper (II)-incorporated iminophenol containing porous polymer (Cu-TAzo-TAPB), which was reported to be a recyclable catalyst for click reactions, is now exploited as an efficient catalyst in the solvent-free one-pot process to make 3,4-dihydropyrimidinone derivatives (DHPMs) by a three-component condensation reaction of urea/thiourea, aldehydes, and active methylene compounds. Usually, these reactions are complicated to carry out in a neutral medium. We describe here an eco-friendly method to produce Biginelli products with 5 mol% catalyst loading with a simple isolation technique. The high product yields show the effective Biginelli reaction technique. The catalyst is highly stable and easily recoverable for reuse without significant loss of catalytic efficiency. [ABSTRACT FROM AUTHOR]

In this work, we develop an in situ biomass-confined approach to fabricate an atomically dispersed Fe/NC catalyst for ORR. The acquired Fe/NC demonstrates glorious oxygen reduction reaction (ORR) activity (E1/2: 0.858 V) in alkaline media and long-term cycling stability (∼750 h) in a homemade liquid zinc-air battery. [ABSTRACT FROM AUTHOR]

The homoleptic hydroxy-pyridine functionalized Co(III)–NHC complex (2) demonstrates extraordinary catalytic activity towards the CO2 cycloaddition under mild conditions. Using this catalyst and TBAB, the highest TON (666 667) and TOF (52 713 h−1) were achieved compared to previously reported cobalt catalysts. [ABSTRACT FROM AUTHOR]

Nickel catalysis is a well-established and powerful tool for C–C cross-coupling reactions, and its versatility has expanded significantly over past decades by its combination with visible-light photocatalysis in metallaphotoredox chemistry. Photocatalysis enables the activation of traditionally inert substrates and turnover of the Ni catalyst through a single-electron transfer processes. In recent years, dual catalysis has been further empowered by photoactive Ni intermediates, which exhibit distinct reactivity profiles from their ground states and complement existing protocols. This short review focuses on the emergent subclass of metallaphotoredox catalysis in which the synergy of a photoactive Ni catalyst and a typical photocatalyst (e.g., a polypyridyl Ir complex) provide solutions to challenging C–C bond formation. 1 Introduction 2 Photoactive Nickel Complexes 3 HAT-Mediated C–C Cross-Coupling 4 Halofunctionalization of π-Systems 5 Photoelimination of an Aryl Radical 6 Conclusion [ABSTRACT FROM AUTHOR]

We report an HN-ZIF-67 catalyst with a large hollow structure and well-dispersed active sites by a facile diffusion-controlled strategy. Compared with the pristine ZIF-67 and semi-sealed ZIF-67, HN-ZIF-67 shows remarkable catalytic activity in the hydrogenation of nitro-compounds due to its highly dispersed active sites that are exposed to the substrate, and long cycle life. [ABSTRACT FROM AUTHOR]

In this study, we utilized a one-pot calcination process of zeolitic imidazolate frameworks (ZIFs) to create ZnSe/CoSe2@N-doped C composites. These serve as cost-effective and efficient alternatives to precious-metal-based catalysts for water electrolysis. The synthesis process addresses the issue of Co agglomeration, a common factor that typically degrades electrocatalytic performance, by incorporating Zn into the ZIF structure. This addition stabilizes the compound during electrolysis, preventing degradation. Optimizing the Zn/Co ratio is essential for enhancing the oxygen evolution reaction (OER). Our results demonstrate that adjusting this ratio leads to a significant improvement in mass activity. Through extensive physical and electrochemical analyses, we confirmed the synergistic interactions between Zn and Co, underscoring the potential of ZnSe/CoSe2@N-doped C composites as durable electrocatalysts. This study not only advances catalyst design for water electrolysis through metal stoichiometry manipulation but also promotes the development of economical and efficient water-splitting systems. [ABSTRACT FROM AUTHOR]

[Display omitted] The Sabatier principle in heterogeneous catalysis provides guidance for designing optimal catalysts with the highest activity. We report a new Sabatier phenomenon induced by nanoclusters on different atomic scales in gas-sensitive reactions. We prepared a series of Ag nanocluster catalysts with coordination structures ranging from Ag 0 to Ag 13 through a surface coordination strategy. When used as catalysts for gas-sensitive reactions, a volcano-type relationship between the coordination number of Ag nanoclusters and gas-sensitive activity emerges, with a summit at a moderate coordination of Ag 5. Mechanistic studies show that the efficient adsorption of activated *C 2 H 6 O on electron-rich Ag 5 clusters is a key factor for the Sabatier phenomenon (adsorption energy from −0.322 eV to −0.663 eV), which leads to highly selective sensing. We found that the catalyst electron-rich surface layer induced by Ag 5 clusters serves as a descriptor to explain the structure–activity relationship. Furthermore, due to the well-defined geometric and electronic structures in the Ag 5 clusters, the optimized catalyst achieves both maximum activity and selectivity in chemoselective sensing reactions. This study reveals the Sabatier principle and provides insightful guidance for the rational design of more efficient and practical nanocluster catalysts for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction (CO2RR) offers a promising avenue to address rising atmospheric CO2 levels by producing high‐value chemicals. However, the development of efficient, long‐lasting catalysts remains challenging. In this study, particle swarm optimization is employed to design a novel bimetallic boronene structure, thereby enhancing CO2RR activity through precise tuning of the metal‐substrate microenvironment. Through high‐throughput screening, seven CuMB4 (M = V, Zn, Nb, Ag, Cd, Ta, Au) monolayers are identified as promising CO2RR catalysts based on stability, conductivity, catalytic activity, and selectivity. These materials, characterized by hyper‐coordination and neighboring bimetallic effects, are proposed for synthesis via self‐assembled surface growth. Notably, CuZnB4 exhibited exceptional theoretical catalytic activity, characterized by remarkably low limiting potentials (UL) of −0.16 V for CH4 and −0.27 V for C2H4, as well as low kinetic barriers of 0.65 and 0.53 eV, respectively. The enhanced activity results from neighboring effects optimizing densely populated boron active sites and the ability to suppress hydrogen evolution reactions. Additionally, this study explored intrinsic properties influencing catalytic activity using volcano plots, descriptor analysis, and electron density evaluation. Unlike traditional catalysts prone to oxidation, CuMB4 varieties possess self‐activating properties, facilitating the conversion of *O/*OH to H2O and enhancing CO2 conversion. This research introduces robust CO2RR catalysts and provides insights into manipulating neighboring effects, thus guiding future catalyst design. [ABSTRACT FROM AUTHOR]

Emerging atomically dispersed metal catalysts (ADCs), especially carbon−based ADCs have arguably received enormous attention in diverse electrochemical energy conversion processes. Such catalysts have well−defined active centers, and their geometric and electronic structures depend greatly on their coordination microenvironments, which, in turn, govern the performances in the realm of electrocatalysis. In this review, it is focused on the state−of−the−art synthesis strategies for carbon−based ADCs, with particular emphasis on their microenvironment modulations. The advances in characterizing the microenvironment alongside understanding the synthetic pathway are outlined, and exemplified in electrochemical applications, including electrocatalytic H2 evolution, O2 evolution/reduction, CO2 reduction, and Li polysulfides conversion reactions. Rather than focusing on the catalysis metrics, this review delved deeply into the underly science and the associated reaction mechanisms of these catalysts in diverse electrochemical systems. The fundamental impacts of the microenvironments of the catalysts on electrocatalytic activities, selectivities, and stabilities are discussed. In the end, it is concluded by highlighting the current issues of the microenvironment engineering of these carbon−based ADCs and propose the prospects for future opportunities and challenges. [ABSTRACT FROM AUTHOR]

The combined use of O2 and CO2 as oxidizing agents in the oxidative coupling of methane (OCM) has been assessed over two representative OCM catalysts, i. e., La−Sr/CaO and NaMnW/SiO2, under a wide range of inlet O2 and CO2 concentrations. The overall impact of CO2 was found to depend on the operating conditions and the catalyst used. At O2‐rich conditions, a negative effect of CO2 was observed on C2 selectivity. At O2‐lean conditions, a positive effect of CO2 on both catalysts was observed, likely originating from an enhanced dehydrogenation of C2H6 to C2H4 and limited deep oxidation of the involving hydrocarbons and reaction intermediates. The behavior induced by CO2 is attributed to its mild oxidizing ability and interactions with the catalysts. The enhanced dehydrogenation of C2H6 was observed and confirmed by specific tests with a CO2 and C2H6 feed. Well‐controlled CO2 addition improved the value of the OCM product mixture, mainly due to a 9 % increase in C2H4 and a 19 % increase in CO selectivity, resulting in a 25 % reduction of CO2 at the outlet over the La−Sr/CaO catalyst. These findings provide new insight into the CO2 effect on OCM and the data to translate this research into OCM process alternatives. [ABSTRACT FROM AUTHOR]

Here we report on the use of formic acid as a green and safe reagent for the N‐methylation of primary amides in the presence of a Pd/In2O3 solid catalyst. No additive is needed and primary amides are selectively N‐methylated in good to excellent yields. The reaction operates through a formylation/reduction pathway, leaving the amide carbonyl untouched. [ABSTRACT FROM AUTHOR]

The hydrogenation of acetylene to ethylene is of great industrial interest. Achieving both high selectivity and high conversion of acetylene to ethylene via semi‐hydrogenation is quite challenging. Bimetallic catalysts offer opportunities to selectively control reaction pathways by altering the electronic and geometric properties of active sites on the catalyst surface. Recent advancements in the synthesis of bimetallic catalysts enabled the creation of random alloys, intermetallics, segregated structures, or single‐site alloys with precision. These catalysts could be tailored for semi‐hydrogenation of acetylene by tuning the features including adsorption energy, active site isolation, and the d‐band center. Modern machine learning tools are also helpful for catalyst design. In this article, an overview of the conceptual advances in the design aspects of bimetallic catalysts, advances and challenges involved in the acetylene semi‐hydrogenation, has been presented. [ABSTRACT FROM AUTHOR]

Developing advanced electrocatalysts toward the cathodic oxygen reduction reaction is essential for the large‐scale application of fuel cells. Pt‐based catalysts have been known to exhibit optimal ORR performance compared with other metal‐based counterparts. However, their long‐term stability and toxic tolerance still need further improvement. Numerous optimization strategies have been employed in the past few years to enhance the ORR comprehensive performance of Pt‐based electrocatalysts, and tremendous progress has been achieved. Among various optimization strategies, the confinement strategy can not only inhibit the coalescence of catalysts during high‐temperature preparation but also mitigate the aggregation, detachment, and dissolution during the electrochemical process, which motivates this review. After addressing the fundamental ORR mechanism and the superiority of confined strategies, we categorize and review various Pt‐based catalysts confined by different materials, including organic compounds, inorganic oxides and carbon materials. Their synthesis routes are discoursed first, then their structure and performance optimization are highlighted. Subsequently, the principle of confinement strategy to enhance the catalyst ORR performance is also discussed. Finally, the challenges and perspectives on the materials selection, synthesis design, technology improvement, and practical application of confined Pt‐based catalysts are proposed. [ABSTRACT FROM AUTHOR]

A simple, straightforward, and highly efficient greener approach for synthesizing bis(6‐aminouracil‐5‐yl)methane derivatives was developed by employing β‐cyclodextrin‐SO3H as supramolecular catalyst in water at 100 °C. A total of 16 bis(6‐aminouracil‐5‐yl)methanes were synthesized via a one‐pot reaction between substituted aromatic aldehydes, 6‐amino‐1,3‐dimethyluracil, and 10% β‐cyclodextrin‐SO3H in water with 84%–92% yield within 20–120 min. The salient features of this protocol included water as green solvent, β‐cyclodextrin‐SO3H as recyclable supramolecular catalyst, mild reaction conditions, easy isolation of pure products, and good to excellent yields. [ABSTRACT FROM AUTHOR]

Improving the utilization of active sites in carbon catalysts is significant for various catalytic reactions, but still challenging, mainly due to the lack of strategies for controllable introduction of active dopants. Herein, a novel "Ar plasma etching‐NH3 annealing" strategy is developed to regulate the position of active N sites, while maintaining the same nitrogen species and contents. Theoretical and experimental results reveal that the edge‐hosted‐N doped carbon nanotubes (E‐N‐CNT), with only 0.29 at.% N content, show great affinity to peroxymonosulfate (PMS), and exhibit excellent Fenton‐like activity by generating singlet oxygen (1O2), which can reach as high as 410 times higher than the pristine CNT. The remarkable utilization of edge‐hosted nitrogen atom is further verified by the edge‐hosted‐N enriched carbocatalyst, which shows superior capability for 4‐chlorophenol degradation with a turnover frequency (TOF) value as high as 3.82 min−1, and the impressive TOF value can even surpass those of single‐atom catalysts. This work proposes a controllable position regulation of active sites to improve atom utilization, which provides a new insight into the design of excellent Fenton‐like catalysts with remarkable atom utilization efficiency. [ABSTRACT FROM AUTHOR]

A washing step is employed to adjust the residual surface hydroxyl groups on the Cu–TiO2 catalysts, which in turn influences the local environment of copper species. Hydroxyl groups control both copper dispersion and the Cu+/Cu2+ ratio. Notably, a higher [Cu+]/[OH−] ratio is associated with an enhanced reaction rate in CO conversion. [ABSTRACT FROM AUTHOR]

The utilization and transformation of CO2 under mild conditions, particularly at ambient pressure and moderate temperature, remain challenging and attract widespread attention. Ionic liquids are considered to be green and designable solvents, and have high efficiency for CO2 conversion. Here, a novel aprotic ionic liquid, [Ch][Triz], was discovered as a dual-functional catalyst capable of simultaneously activating CO2 and the substrates, and exhibited outstanding performance in catalyzing the cyclization of CO2 and 2-aminobenzonitriles under solvent-free and mild conditions (such as 0.1 MPa, 30–50 °C), affording a range of quinazoline-2,4(1H,3H)-diones in high yields. Furthermore, [Ch][Triz] IL could be easily recovered and reused up to five recycle runs without obvious activity loss. This work proposes a sustainable approach to CO2 conversion, and holds great potential for quinazoline-2,4(1H,3H)-dione preparation under mild conditions. [ABSTRACT FROM AUTHOR]

Cu-based catalysts have been promising materials for electrocatalytic reduction of carbon dioxide into C2+ products. However, the low selectivity of Cu-based catalysts for a single C2+ product limits their application. Herein, this work presents a strategy to modify the coordination environment of Cu-based MOF catalysts through the introduction of different doping atoms, aiming to improve the selectivity towards ethanol products. The CuIn-BTC-DBD catalyst exhibits an ethanol FE of 87% with a partial current density of −17 mA cm−2 at −1.4 V vs. RHE. Through experimental investigations, we reveal the modulation of the coordination environment of Cu-based MOFs through the doping of In atoms. This strategy improves the selectivity for ethanol products. This study provides a new approach to designing bimetallic Cu-based MOF electrocatalysts with high efficiency, mild conditions, and stable CO2RR to ethanol products. [ABSTRACT FROM AUTHOR]

Methyl magnesium bromide is a precatalyst for the dehydrocoupling of silanes and amines to produce aminosilane products under mild conditions. As a commercially available Grignard reagent, this precatalyst represents a simplification over previous magnesium-containing catalysts for Si–N bond formation while displaying similar activity to other magnesium-based catalysts. This observation is consistent with the hypothesis that competitive Schlenk equilibrium can be addressed by not using an ancillary ligand. While the activity of MeMgBr is lower than some reported catalysts, including other commercially available precatalysts, unique selectivity was observed for MeMgBr that may allow for directed synthesis of aminosilane products. This work continues to increase the accessibility of Si–N heterodehydrocoupling through a growing family of commercially available precatalysts that balance activity and selectivity. [ABSTRACT FROM AUTHOR]

A novel rosarin di-Cu complex 2Cu-1 and a linear six-pyrrolic mono-copper complex 1Cu-1 were synthesized using rosarin as the ligand. The molecular conformations of these complexes were confirmed by X-ray crystallography. The optical study of 1Cu-1 indicated NIR-II absorption due to the long six-pyrrolic ligand and the ICT effect. The 2Cu-1 complex exhibited a very narrow electronic reduction–oxidation gap of 0.50 eV, attributed to the antiaromatic characteristics of the rosarin ring. The first HER study of the di-copper rosarin complex 2Cu-1 indicated that the multi-metal poly-pyrrolic complexes are promising molecular hydrogen evolution reaction catalysts. [ABSTRACT FROM AUTHOR]

Fluorite-type nanocrystalline 5% iron-substituted ceria (Ce0.95Fe0.05O2−δ) was synthesized by the solution combustion method with an average crystallite size of 15 nm. The catalyst was well characterized by SEM, EDX, XPS, XRD, and H2-TPR studies, which confirmed the substitution of Fe3+ in the CeO2 lattice. This precious metal-free catalyst was developed for the selective conversion of various arylboronic acids to the corresponding biphenyls and phenols employing K2S2O8 and H2O2, respectively. This catalyst could be coated on cordierite monolith, which acts as a catalyst cartridge employed efficiently in recycling experiments up to seven cycles. The scale-up reaction was also carried out with a catalyst cartridge, affording a good yield of the desired product. [ABSTRACT FROM AUTHOR]

Zinc-air batteries (ZABs) have received considerable interest because of the growing demand for high-energy–density and safe energy storage systems. Efficient and economical catalysts for the cathodic oxygen reduction reaction (ORR) in ZABs play a crucial role in reducing expenses and facilitating industrialization. In this study, an efficient alkaline ORR electrocatalyst derived from ZIF-67 is synthesized by a simple one-pot method followed by high-temperature calcination. The optimized catalyst, CoCu-NPC-1000, demonstrates outstanding electrocatalytic performance in ORR, with a half-wave potential (E1/2) of 0.849 V and an onset potential (Eonset) of 0.988 V. Notably, CoCu-NPC-1000 also shows excellent methanol tolerance, stability, and durability under alkaline conditions. These superior catalytic properties are attributed to the synergistic effect of Co-Nx and Cu-Nx dual active sites, along with the increased average pore diameter facilitated by the pore-forming agent Zn(NO3)2·6H2O. The CoCu-NPC-1000-based zinc-air battery outperforms the power density of Pt/C, achieving 107.1 mW cm⁻2 at a current density of 124.3 mA cm⁻2, compared to 84.79 mW cm⁻2 at 143 mA cm⁻2 for Pt/C. Additionally, its specific capacity reaches 851 mAh g Zn - 1 , exceeding that of Pt/C (688 mAh g Zn - 1 ). This study not only confirms the effectiveness of Zn(NO3)2·6H2O as a pore-forming agent but also offers valuable insights into synthesizing bimetallic organic framework-derived electrocatalysts for ZABs. [ABSTRACT FROM AUTHOR]