ABSTRACT Constructing highly efficient and stable non‐noble metal catalysts for selective hydrogenation of nitroarenes is a very appealing yet challenging task in the fields of materials science and catalysis. Herein, a series of N‐doped carbon‐anchored Zn single‐atom catalysts were prepared by pyrolyzing the biomass‐based composite precursors composed of chitosan, tannic acid, and ZnCl 2 . The optimal sample of Zn‐Cl/NC‐3_900 displays superior catalytic activity with a turnover frequency of 4817 h −1 at 80°C, selectivity (∼99%), and recyclability (without any post‐treatment) for hydrogenation of p ‐chloronitrobenzene to p ‐chloroaniline with N 2 H 4 ·H 2 O. Its catalytic performance is well kept even after HCl or KSCN treatments, revealing excellent chemical stability and anti‐poisoning capability. Additionally, a very high p ‐chloroaniline selectivity (∼98%) could be obtained under mild conditions (1.0 MPa, 100°C) when H 2 is used as reductant. Characterization results and theory calculations demonstrate that introducing an appropriate amount of N/Cl species may finely modulate the local coordination environments of Zn single‐atoms. The resultant axially Cl‐coordinated ZnN 2 sites (Zn‐N 2 Cl) possess moderated adsorption/desorption capability and lower activation barriers, in line with the Sabatier principle, thereby significantly boosting the catalytic hydrogenation performance. This work provides a simple and effective approach for developing efficient hydrogenation catalysts through manipulating the coordination structure of metal single‐atom sites.

Colloidal quantum dots (CQDs) are ideal for room-temperature gas sensors due to their high surface area, abundant dangling bonds, and excellent film-forming properties. However, the underlying conduction mechanism remains unclear, lacking in-depth analysis of gas-solid charge transfer and carrier transport, which hinders the rational design of high-performance gas sensors. To address this, we fabricated a PbS colloidal quantum dot thin-film transistor (TFT) gas sensor that enables in situ analysis of carrier concentration and mobility via gate voltage modulation. We systematically measured the variations in conductivity, carrier concentration, and mobility with NO2 concentration and established a normalized weight variation model. The results show that the conductivity increase upon NO2 exposure is primarily due to the rise in carrier concentration induced by gas adsorption. At low concentrations (below 0.5 ppm), the response is dominated by mobility variation. This work provides a physically meaningful theoretical framework for understanding the conduction mechanism.

Fe 3 @NG enables deep reduction toward CH 4 , while Cu 3 @NG is limited by CO hydrogenation.

Constant-potential DFT reveals distinct CO2 reduction behavior on Fe3 and Cu3 clusters supported on N-doped graphene. Fe3@NG enables deep reduction toward CH4 at mild cathodic bias, whereas Cu3@NG remains limited by uphill *CO hydrogenation. This contrast originates from Fe-induced electronic modulation that promotes CO2-derived intermediate activation.

Formic acid dehydrogenation (FAD) is a promising approach for sustainable H₂ production from renewable liquid feedstock under mild reaction conditions. Twelve single-atom catalysts (SACs) were designed by anchoring six transition metals (Ru, Rh, Pd, Os, Ir, and Pt) to pristine graphdiyne (GDY) and amino-modified GDY (am-GDY). Catalytic activity and H₂ selectivity toward FAD were systematically explored using density functional theory (DFT) calculations. All the SACs exhibited excellent thermodynamic stability. Among the unmodified systems, only Ru@GDY and Ir@GDY showed superior activity compared with the benchmark Pd(111) surface. Amino modification has been demonstrated to be a universal and effective strategy for boosting catalytic performance as it modifies the preferred reaction pathway of FAD. This modification substantially boosted the activity of most SACs, with Rh@am-GDY and Ir@am-GDY exhibiting simultaneous enhancements in both activity and H₂ selectivity. Notably, Ir@am-GDY demonstrated the highest activity, with an ultralow energetic span of 0.86 eV. Electronic structure analysis indicated that the -NH₂ groups triggered electronic redistribution at the metal centers, stabilized the key mono-HCOO intermediate, and optimized reactant adsorption, thus improving catalytic efficiency. This study established amino modification as a robust strategy for designing high-performance SACs for hydrogen production from formic acid.

Electrolytic reduction of nitrogen offers a route to NH3 synthesis under ambient conditions, yet the design of efficient electrocatalysts remains challenging. Here, we systematically investigate 52 vacancy-anchored single--atom catalysts (SACs), TM-Nx (x = 2, 3), on defective graphene substrate using density functional theory. Stability analyses confirm strong metal-support binding, and free-energy screening of adsorption and elementary steps identifies 14 promising candidates. We show that vacancy-engineered coordination cavities (TM-N2/ N3) tailor the active-site microenvironment, thereby governing N2 adsorption geometry (end-on vs side-on), pathway selection, and the resulting limiting potentials (UL). In particular, Mo-N3, stabilized by an N3 cavity, favors a side-on-derived mixed pathways and delivers UL =-0.12 V. Electronic analyses reveal that donation-backdonation interaction weakens the N---N bond, and facilitates activation across coordination motifs. These trends are further consolidated by a SISSO-derived descriptor (phi) that captures d-orbital and ligand-field contributions, within a unified physical picture. Selectivity analysis highlights two SACs (W-N3 and Mo-N3) with superior selectivity over hydrogen evolution reaction, and ab initio molecular dynamics simulations confirm their thermal robustness. This work provides mechanistic insights and design principles for engineering SACs toward efficient ammonia electrosynthesis.

Designing efficient and selective electrocatalysts for the nitrogen reduction reaction (NRR) remains a critical challenge due to the chemical inertness of N2 and the competing hydrogen evolution reaction (HER). In this study, we systematically investigate 78 TM@N2C2 single-atom catalysts, which consist of 26 transition metals anchored to a graphene framework. Three coordination motifs (Type A-C) were constructed to represent different spatial arrangements of N and C ligands. Formation energies and dissolution potential calculations demonstrate the thermodynamic and electrochemical stability of the designed structures. NRR activity and selectivity were assessed through comprehensive reaction pathway analysis, adsorption energy screening (Delta G*N2 vs. Delta G*H), and limiting potential (UL) calculations. The screening strategy identified five promising catalysts with high intrinsic activity and HER suppression: Re@N2C2 (Type A) and Ru, W, Re, and Os@N2C2 (Type B). The sureindependence screening and sparsifying operator (SISSO) analysis revealed that the dz2 band center strongly correlates with UL, providing electronic-level insight into activity trends. Further analysis using charge density difference, projected density of states (PDOS), and integrated-crystal orbital Hamilton population (ICOHP) confirmed a cooperative sigma-donation and pi*-backdonation mechanism facilitating N equivalent to N bond activation. Finally, ab initio molecular dynamics (AIMD) simulations verified the thermal stability of the top-performing catalysts under operating conditions. Importantly, comparative analysis with TM@N4 analogues revealed that the N2C2 coordination environment enables shallower dz2 states and more favorable UL, highlighting the critical role of ligand field modulation in boosting NRR activity. These findings offer mechanistic understanding and design guidance for developing robust, selective, and active NRR electrocatalysts.

The chemical microenvironment surrounding metal nanoparticles (NPs) plays crucial roles in regulating their electronic structures. However, due to the lack of quantitative descriptor, such effect has been understood largely in a qualitative manner. To address this issue, a series of reticular metal-organic frameworks (MOFs) with diverse functional groups (MIP-206-X, X = OH, OCH3, H, Cl, and F) were synthesized, and Pt NPs with similar sizes and loadings were incorporated to afford Pt@MIP-206-X for ammonia borane methanolysis. X-ray absorption near edge structure (XANES) was adopted to determine the d-orbital occupancy of Pt, and the electronic contribution from MOFs was quantified as the descriptor Δe, which was demonstrated to accurately describe the Pt-methanol adsorption strength (quantified by activation entropy and methanol desorption temperature) and exhibit an excellent linear correlation with catalytic activity. Isotopic analyses and DFT calculations revealed that a larger Δe strengthens methanol adsorption on Pt, promotes O─H bond cleavage as the rate-determining step (RDS), and leads to enhanced activity.

Electrocatalytic glycerol oxidation reaction (GOR) replacing anodic oxygen evolution reaction while coupling cathodic hydrogen evolution reaction (HER) possesses great effect to reduce energy consumption for producing hydrogen and enhance the applied value of anodic product in anion exchange membrane electrolyzer (AEME). However, the overall productivity for anodic and cathodic products is poor due to the difficult C-H bond activation of intermediates during GOR and strong adsorption of OH* intermediates during HER. Here, we realize the phase-selective synthesis of Ni4B3, Ni2B, and Ni3B interstitials and reveal the relationship between activity and atomic arrangement. Ni3B as bifunctional GOR and HER catalysts in AEME obtains 95.4 % formic acid selectivity at 99.9 % glycerol conversion, generates 63.1 L H2 for 57 h under the condition of 0.5 A cm(-2), 5.0 M KOH, and 1.0 M glycerol. Ni3B exhibits strong atomic orbit hybridization between Ni(d) and B(s,p), promoting the desorption of OH* intermediates and thus enhancing the catalytic performance for HER. Besides, B atoms near Ni atom of Ni3B are easily dissolved out during GOR, which facilitates the surface reconstruction and forms a thicker BOx-decorated NiOOH layer, further improving the lattice oxygen reactivity, thus accelerating the C-H bond activation of glyceraldehyde intermediates and enhancing catalytic activity.

ABSTRACT The Cu‐based materials are an important category of catalysts for CO 2 hydrogenation to methanol, in which Cu 0 and Cu + species have been widely acknowledged to play key roles in the reaction. Herein, a series of metal‐organic frameworks (MOFs), namely UiO‐66(n) with exposed ─COOH groups, are fabricated by employing both terephthalic acid and 1,2,4‐benzenetricarboxylic acid linkers. Following by introducing Cu nanoparticles, Cu@UiO‐66(n) are synthesized. By regulating the amount of exposed ─COOH groups on the MOF pore wall, the interaction between Cu and the MOF support is regulated. This ─COOH microenvironment regulates the overall Cu 0 /Cu + ratio in the supported Cu species, thereby tuning the Cu 0 /Cu + interfacial descriptor, which is closely associated with the CO 2 hydrogenation performance. The Cu@UiO‐66(25) featuring the longest Cu 0 /Cu + interface achieves a methanol space‐time yield of 694 g kg cat −1 h −1 and methanol selectivity of 92.8% at 250 °C and 4 MPa, far surpassing other counterparts. This work provides a deep understanding of the synergistic effect between Cu 0 and Cu + species in catalytic CO 2 hydrogenation.

Ammonia electrosynthesis from N2 under mild conditions has attracted intense interest, yet practical electrocatalytic nitrogen reduction (NRR) remains limited by the high barrier for activating the N equivalent to N bond and by the competing hydrogen evolution reaction (HER) that preferentially consumes proton-electron pairs. In this work, we design a graphene-supported single-atom motif anchored by a dual-nitrogen cavity (N2cav) and conduct a spin-polarized density functional theory based screening over a library of 78 TM-N2cav candidates generated by combining 26 transition-metal centers with three local coordination microenvironments (pyrrolic, pyridinic, and mixed). After thermodynamic stability filtering, the retained structures are further evaluated by *N2 adsorption feasibility and by two representative proton-coupled electron-transfer (PCET) steps (*N2 -> *NNH and *NH2 -> *NH3), yielding 17 catalysts for complete free-energy pathway analysis. The cavity confinement enforces end-on *N2 binding across the selected systems, whereas the subsequent hydrogenation landscape diverges into distal, alternating, or mixed routes depending on the "metal center-coordination environment" combination, leading to distinct potential-determining steps and limiting potentials (UL). Among all candidates, Ru-N2cav-P delivers the most favorable activity with UL = -0.23 V. Considering HER competition, five catalysts satisfy both adsorption and potential-window criteria for NRR selectivity. Finally, applying SISSO to the independently screened dataset, we derive an interpretable composite descriptor phi that rationalizes UL variations in terms of coordinationmodulated metal d-state features, providing transferable guidelines for the rational design of cavity-anchored NRR single-atom catalysts.

Lithium-carbon dioxide batteries hold promise for coupling CO2 utilization with high-energy–density storage, yet their practical application is limited by poor reversibility and large charge–discharge polarization arising from discharge-product chemistry. Here, using TM-PtTe single-atom catalysts as a model platform, we show that the identity of atomically dispersed catalytic sites governs an early-stage bifurcation between carbonate- and oxalate-mediated pathways, thereby predetermining the subsequent charging route and full-cycle polarization. Ru-, Rh-, Ir-, and Pt-based sites favor Li2CO3-related nucleation, whereas Pd- and Os-based sites switch the reaction toward oxalate chemistry; both Pd-PtTe and Os-PtTe can stabilize Li2C2O4 as a terminal discharge product, with Os-PtTe exhibiting the most favorable overall energetics. This oxalate-mediated chemistry bypasses the highly penalized Li2CO3 decomposition landscape and reduces the total overpotential from 0.83 V on Ru-PtTe to 0.22 V on Os-PtTe. Representative explicit-DMSO calculations further indicate that Li-O coordination stabilizes Li-containing intermediates while preserving the qualitative oxalate preference, yielding a calculated total overpotential of 0.18 V in the sampled DMSO environment. These results identify discharge-product selection as a materials-level descriptor for reversibility and polarization in Li-CO2 batteries and provide a clear design principle for developing low-polarization cathodes

The electrochemical nitrogen reduction reaction (NRR) provides a sustainable route to ammonia synthesis, but its efficiency is hindered by the inert N≡N bond and competing hydrogen evolution reaction (HER). Herein, we systematically screened 25 transition-metal (TM) single-atom catalysts (SACs) supported on goldene, denoted as TM@Auene, using density functional theory (DFT). Sixteen TM@Auene systems capable of end-on N2 adsorption were evaluated across distal, alternating, and mixed NRR pathways. Mo@Auene and Re@Auene exhibited high NRR catalytic activity with low limiting potentials of -0.04 and -0.10 V, respectively, associated with effective N2 activation through synergistic σ-donation and π*-back-donation. A volcano-type relationship was established between NRR activity and occupied d-electron number, positioning Mo and Re near the optimum. HER competition was assessed, with Nb@Auene, Mo@Auene, W@Auene, Re@Auene, and Os@Auene showing favorable NRR selectivity. For Mo@Auene and Re@Auene, Pourbaix diagram analysis and ab initio molecular dynamics (AIMD) simulations provide preliminary support for electrochemical stability and short-timescale structural integrity under NRR-relevant conditions. These results identify Mo@Auene as a promising NRR candidate and highlight Auene-supported SACs as a descriptor-guided platform for catalyst design.

The paired electrochemical refining process of glycerol electrooxidation reaction (GEOR) coupling with cathodic hydrogen evolution reaction (HER) in anion exchange membrane electrolyzer (AEME) has attained extensive attention, because it can realize the decentralized co-generation of value-added chemicals and hydrogen. However, the high bond energy of C(sp3)-H bonds in glycerol put a formidable challenge to realize the sufficient activation. This seriously hinders the enhancement of single product selectivity and hardly obtains high current density for the AEME. Herein, we design Ni3B metallene to drive glycerol-to-formic acid (FA) conversion for GEOR. Furthermore, Ni3B metallene as anodic GEOR catalyst and commercial Pt/C as cathodic HER catalyst in AEME exhibit high glycerol conversion (97.1 %), yield 96.5 g FA product, and obtain 81.7 L H2 for 75 h under 0.5 A/cm2. Theoretical calculation, in situ Raman, and X-ray absorption near-edge structure spectroscopy results demonstrate that the decreased d-p band center distance at Ni3B metallene-derived BOx-NiOOH active phase, obtained by surface reconstruction, unlocks the lattice oxygen, promoting the C-H bond activation of glycerol reactant/glyceraldehyde intermediate, reducing the energy barrier of rate-determining step (dehydrogenation of glyceraldehyde) for GEOR, and thus improving the overall catalytic performance of AEME.

Direct seawater electrolysis greatly alleviates the shortage of freshwater resources, emerging as a promising approach for hydrogen production. Unfortunately, the slow kinetics of oxygen evolution reaction (OER) and the complex seawater environment, especially the chloride oxidation reaction (ClOR), pose significant challenges for the design of direct seawater electrolysis catalysts. For the sake of enhancing corrosion resistance to chloride ions (Cl-), an alkaline environment is settled for increasing the potential difference between OER and competitive ClOR. NiFe-LDH has been recognized as a benchmark catalyst in alkaline environment owing to its unique advantages. However, in strongly alkaline environment, the deposition of Mg(OH)2 and Ca(OH)2 at the cathode limits the overall efficiency of direct seawater electrolysis. In this study, we have investigated the underlying effect of four different interlayer anions (PO43-, SO 4 2- , CO 3 2- , and NO3-) on the OER activity, selectivity, and pH application range of NiFe-LDH using density functional theory. Furthermore, we have explored the intrinsic correlations between electronic structure and catalytic performance. Our results confirm that the interlayer anions play a favorable role in promoting OER activity. Among them, NiFe-LDH with PO 4 3- remarkably outperforms the other interlayer anions in terms of OER activity and selectivity, reducing the OER overpotential (eta) to 0.29 V and overcoming the limitations associated with high pH conditions. Most importantly, there is a linear

Inspired by the active site of methane monooxygenase, we designed a Cu2O cluster anchored in the six-membered nitrogen cavity of a C2N monolayer (Cu2O@C2N) as a stable and efficient enzyme-like catalyst. Density functional theory (DFT) calculations reveal that the bridged Cu-O-Cu structure within C2N exhibits strong electronic coupling, which is favorable for methanol formation. Two competing mechanisms—the concerted and radical-rebound pathways—were systematically investigated, with the former being energetically preferred due to lower energy barriers and more stable intermediate states. Furthermore, strain engineering was employed to tune the geometric and electronic structure of the Cu-O-Cu site. Biaxial strain modulates the Cu-O-Cu bond angle, adsorption properties, and d-band center alignment, thereby selectively enhancing the concerted pathway. A volcano-like trend was observed between the applied strain and the methanol formation barrier, with 1% tensile strain yielding the overall energy barrier to methanol formation (ΔGoverall) as low as 1.31 eV. N2O effectively regenerated the active site and demonstrated strain-responsive kinetics. The electronic descriptor Δε (εd − εp) captured the structure–activity relationship, confirming the role of strain in regulating catalytic performance. This work highlights the synergy between geometric confinement and mechanical modulation, offering a rational design strategy for advanced C1 activation catalysts.

As a negative charge carrier, the hydride ion (H-) is more energetic, polarizable and reactive than cations1. An H--mediated electrochemical process is fundamentally different from existing systems and enables the development of innovative electrochemical devices, such as rechargeable batteries, fuel cells, electrolysis cells and gas separation membranes2. Here we developed a core-shell hydride 3CeH3@BaH2, which exhibits fast H- conduction at ambient temperature and becomes a superionic conductor above 60 °C. This hydride allows us to construct an all-solid-state rechargeable H- battery CeH2|3CeH3@BaH2|NaAlH4, which operates at ambient conditions using NaAlH4 and CeH2 as cathode and anode materials, respectively. This battery has an initial specific capacity of 984 mAh g-1 and retains 402 mAh g-1 after 20 cycles. Using hydrogen as charge carriers can avoid the formation of detrimental metal dendrites, in principle, which creates new research avenues for clean energy storage and conversion.

The microenvironment around catalytic sites plays crucial roles in enzymatic catalysis while its precise control in heterogeneous catalysts remains challenging. Herein, the coordinatively unsaturated metal nodes of Hf-based metal-organic framework nanosheets are simultaneously codecorated with catalytically active Co(salen) units and adjacent pyridyl-substituted alkyl carboxylic acids via a post modification route. By varying pyridyl-substituted alkyl carboxylic acids, the spatial positioning of the N atom in pyridine group relative to adjacent Co(salen) can be precisely controlled. Notably, the 3-(pyridin-4-yl)propionic acid, with para-position pyridine N atom, maximally improves the electrocatalytic CO2 reduction performance of Co(salen) unit, far superior to other counterparts. Mechanism investigations reveal that the pyridine unit of 3-(pyridin-4-yl)propionic acid is optimally positioned relative to Co(salen) and undergoes in situ reduction to pyridinyl radical under working potentials. This greatly facilitates the stabilization of *COOH intermediate via hydrogen-bonding interaction, lowering the formation energy barrier of *COOH and therefore boosting CO2 electroreduction.

Supported Co-based catalysts have shown great potential to replace noble-metal catalysts in the selective hydrogenation of substituted nitroarenes, while their tendency to deactivate during hydrogenation remains a major challenge. Here we report a facile method for constructing graphite/SiO2 double-confined Fe-Co nanoalloys, which catalyze hydrogenation of halogenated nitroarenes to halogenated anilines with high yields (> 98 %) under mild conditions. The unique double-confined structure provides effective protection for the alloy core from leaching and oxidation, leading to exceptional stability and recyclability that is unachievable by other supported or confined Co-based catalysts. Additionally, a harmonious amphiphilic environment is created to enhance the mass transport capability and to inhibit deactivation during catalytic process. Density functional theory (DFT) calculations reveal that the electron-enriched graphite-layers serve as effective active sites for selective hydrogenation via a distinct mechanism, thereby improving the hydrogenation efficiency. This design concept and synthesis approach are expected to advance the development of more efficient and stable earth-abundant metalbased catalyst for selective hydrogenation catalysis.