The pursuit of sustainable hydrogen production has positioned water electrolysis as a cornerstone technology for global carbon neutrality. However, sluggish kinetics, catalyst scarcity, and system integration challenges hinder its widespread deployment. Ultrathin two-dimensional (2D) materials, with their atomically exposed surfaces, tunable electronic structures, and defect-engineering capabilities, present unique opportunities for next-generation electrocatalysts. This review provides an integrated overview of ultrathin 2D electrocatalysts, discussing their structural diversity, synthetic routes, structure-activity relationships, and mechanistic understanding in water electrolysis processes. Special focus is placed on the translation of 2D materials from laboratory research to practical device implementation, emphasizing challenges such as scalable fabrication, interfacial engineering, and operational durability in realistic electrolyzer environments. The role of advanced characterization techniques in capturing dynamic structural changes and active site evolution is discussed. Finally, we outline future research directions, emphasizing the synergy of machine learning-driven materials discovery, advanced operando characterization, and scalable system integration to accelerate the industrial translation of 2D electrocatalysts for green hydrogen production.

Proton exchange membrane water electrolysis (PEMWE) has garnered significant attention as a pivotal technology for converting surplus electricity into hydrogen for long-term storage, as well as for providing high-purity hydrogen for aerospace and high-end manufacturing applications. With the ongoing commercialization of PEMWE, advancing iridium-based oxygen evolution reaction (OER) catalysts remains imperative to reconcile stringent requirements for high activity, extended longevity, and minimized noble metal loading. The review provides a systematic analysis of the integrated design of iridium-based catalysts in PEMWE, starting from the fundamentals of OER, including the operation environment of OER catalysts, catalytic performance evaluation within PEMWE, as well as catalytic and dissolution mechanisms. Subsequently, the catalyst classification and preparation/characterization techniques are summarized with the focus on the dynamic structure-property relationship. Guided by these understandings, an overview of the design strategies for performance enhancement is presented. Specifically, we construct a mathematical framework for cost-performance optimization to offer quantitative guidance for catalyst design. Finally, future perspectives are proposed, aiming to establish a theoretical framework for rational catalyst design.

Photocatalytic synthesis of hydrogen peroxide (H₂O₂) has emerged as a promising approach because of its simplicity and environmental benefits. However, significant challenges remain obstacles to their advancement, such as the rapid recombination of photogenerated charge carriers and sluggish surface redox reactions on nonmetallic organic catalysts. Metal-based organic catalysts with tunable electronic structures are considered ideal for exploring the mechanisms and structure-performance relationships in H₂O₂ synthesis. This review summarizes the fundamental principles of photocatalytic H₂O₂ synthesis via oxygen reduction and water oxidation reactions. Recent advancements in electronic structure tuning strategies for metal-based organic catalysts are critically examined, focusing on their impact on light absorption range, photogenerated carrier separation, O₂ activation, and the selective generation of H₂O₂. In addition, this review comprehensively evaluates the applications of sacrificial agents in photocatalytic reaction systems and offers insights into the future development of metal-based organic catalysts for H₂O₂ photosynthesis.

The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_x catalysts. This study investigated the sulfation mechanism of the CoMn₂O₄/CeTiO_x (CMCT) catalyst during the selective catalytic reduction of NO_x with NH₃ under conditions containing H₂O and SO₂ at 150 °C. Employing a comprehensive suite of time-resolved analysis and characterization techniques, the evolution of sulfate species was systematically categorized into three stages: initial rapid surface sulfate accumulation, the transformation of surface sulfates to bulk metal sulfates, and partial sulfates decomposition after the removal of H₂O and SO₂. These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies, whereas surface sulfates (including ammonium sulfates and surface-coordinated metal sulfates) cause reversible performance loss through decomposition. Furthermore, the competitive adsorption of H₂O and SO₂ significantly influences the catalytic efficiency, with H₂O suppressing SO₂ adsorption while simultaneously enhancing the formation of Brönsted acid sites. This research underscores the critical role of sulfate dynamics on catalyst performance, revealing the enhanced SO₂ resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway. Collectively, the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.

The influence of electronic structure on the performance of catalysts for peroxymonosulfate (PMS) activation remains ambiguous. In this study, the 3d electron configuration of Fe(III) in AgFeO₂ was atomically regulated using cobalt doping. The amount of PMS adsorbed and the catalytic performance were positively correlated with the total effective magnetic moment and the ratios of high-spin Fe(III) and e_g filling within the catalysts. These 3d electron regulations favor PMS adsorption and electron transfer owing to the lower PMS adsorption energy, increased electronic states near the Fermi level, and reduced dz² orbital occupancy. Benefiting from fine tailoring of the electron configuration, the AgFe_0.80Co_0.20O₂ catalyst exhibited outstanding catalytic PMS activation and favorable application potential, achieving efficient pharmaceutical wastewater treatment and more than 80% ofloxacin removal after 72 h of continuous-flow operation. Notably, this study offers a comprehensive understanding for the influence mechanism of electronic structure regulation on PMS activation, providing design guidance for the development of efficient heterogeneous Fenton-like catalytic systems.

Effective lattice oxygen (O_latt) activation at low temperatures has long been a challenge in catalytic oxidation reactions. Traditional thermal catalytic soot combustion, even with Pt/Pd catalysts, is inefficient at exhaust temperatures below 200  °C, particularly under conditions of frequent idling. Herein, we report an effective strategy utilizing non-thermal plasma (NTP) to activate O_latt in Ce_1-xCo_xO_2-δ catalysts, achieving dramatic enhancement of the soot combustion rate at low temperatures. At 200 °C and 4.3 W (discharge power, P_dis), NTP-Ce_0.8Co_0.2O_2-δ achieved 96.9% soot conversion (X_C), 99.0% CO₂ selectivity (S(CO₂)) and a maximum energy conversion efficiency (E_max) of 14.7 g kWh^-1. Compared with previously reported results, NTP-Ce_0.8Co_0.2O_2-δ exhibits the highest S(CO₂) and E_max values. Remarkably, even without heating, X_C, E_max, and S(CO₂) reached 92.1%, 6.1 g kWh^-1, and 97.5%, respectively, at 6.3 W (P_dis). The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO₂ crystal lattice and forms an asymmetric Ce-O-Co structure, making oxygen “easy come, easy go”, thereby enabling the rapid combustion of soot over NTP-Ce_0.8Co_0.2O_2-δ. This study highlights the great potential of NTP for activating O_latt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.

Constructing new Brönsted acid sites within zeolitic materials holds paramount importance for the advancement of solid-acid catalysis. Zeo-type germanosilicates, a class of metallosilicates with a neutral framework composed of tetravalent Ge and Si oxygen tetrahedrons, are conventionally considered not to generate Brönsted acid sites. Herein, we disclose an abnormal phenomenon with Ge-rich IWW-type germanosilicate (IWW-A) as an example that Ge-enriched germanosilicates are featured by mild Brönsted acidity. Using the art-of-state density functional theory calculation, ¹⁹F magic angle spinning nuclear magnetic resonance, microcalorimetric and ammonia infrared mass spectrometry- temperature-programmed desorption characterizations, the nature of germanosilicate's Brönsted acidity has been demonstrated to be closely related to the neighboring framework Ge-hydroxyl pairs. Besides, the contribution of Ge-OH groups to Brönsted acidity and the role of Ge-pair structure for maintaining mild acid strength have been elucidated. In catalytic cracking of n-hexane and methanol-to-olefins reaction, the IWW-A germanosilicate exhibit high light olefins selectivity, good recyclability and low carbon deposition, outperforming the benchmark zeolite catalyst, ZSM-5 aluminosilicate.

In this study, we investigated Mo-impregnated H-MCM-22 catalysts (denoted Mo/M) for methane dehydroaromatization (MDA) to produce aromatics such as benzene and toluene (BT). We attempted to improve the performance of the MDA catalysts by reducing the amount of Brönsted acid sites (BAS) of the H-MCM-22 supports via hydrothermal dealumination. Among the prepared catalysts, an optimal hydrothermal treatment (HT) of H-MCM-22 supports at 400 °C, followed by Mo impregnation (denoted Mo/M_400), resulted in a reduced and optimal amount of BAS, along with a comparable Mo distribution to Mo/M. Further, Mo/M_400 enhanced BT formation rates (maximum BT formation rate of 5.23 vs. 4.73 mmol_BT·g⁻¹·h⁻¹ for Mo/M); it appears that dealumination-induced reduction in the quantity of BAS altered their spatial interaction with active Mo species, promoting BT and naphthalene formation. Interestingly, the lifetime of intermediate C₂ (ethane and ethylene) formation was also improved for Mo/M_400. Rigorous coke analyses revealed that the decreased coke content in the aromatic-selective 10-membered-ring (10-MR) pores, as well as the ability of the 12-MR pores to accommodate coke deposits over a longer reaction time, improved the stability of Mo/M_400. Nonetheless, for all catalysts, the deactivations of BAS, and subsequently, the active Mo sites were mainly ascribed to coke deposition. The overall enhancement in MDA performance by Mo/M_400 was attributed to the advantages of the optimally reduced BAS, allowing such performance to surpass those of previously reported Mo-based catalysts.

Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals, but their asymmetric synthesis remains challenging especially for those with multiple chiral centers. In this study, IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of (S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl) butanamide (antiepileptic drug Brivaracetam) via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and (S)-2-aminobutylamide with high diastereoselectivity. To further improve the catalytic efficiency of IR104, its mutant D191E/L195I/E253S/M258A (M3) was identified by saturation mutagenesis and iterative combinatorial mutagenesis, which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity (98:2 d.r.). Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme. The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemic α-substituted aldehydo-esters, expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination. Finally, IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale. Using this mutant, various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r. and 96% yields and subsequently converted into γ- and δ-lactams, providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.

Acid-nitrile exchange reaction (transnitrilation) is a state-of-the-art strategy for nitrile synthesis with a promising industrial application. Herein, a dedicated catalytic system for transnitrilation was designed based on remote H-spillover effect by physically mixing Pt nanoparticles-encapsulated in hollow ZSM-5 (Pt@ZSM-5) and Ni-doped Nb₂O₅ (Ni/Nb₂O₅) under 10%-H₂/N₂. The Pt@ZSM-5 acts as a primary active-center for H₂-dissociation over Pt to form H-spillover; while, Ni/Nb₂O₅ serves as an acceptor-site of H-spillover. Upon uptake of the H-spillover, the doped-reversible Ni²⁺/Ni⁺ couples in the Ni/Nb₂O₅ significantly facilitate migrations of proton (Brönsted-acid site) and surface vacancy (Lewis-acid site) throughout its surface, thus enhancing and enriching its surface-acidic sites for the catalytic transnitrilation. Kinetic analysis demonstrates nitrile-activation over Lewis-acid site of Ni/Nb₂O₅ as rate-determining step of the transnitrilation. This research provides a molecular-scale and fundamental understanding of remote H-spillover effect on a solid acid for an improved catalytic performance by in-situ regulation on its surface-acid type and strength.

CO₂ hydrogenation to CH₃OH is of great significance for achieving carbon neutrality. Here, we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts (CZC-G) with optimized interfacial synergy, achieving superior performance in CO₂ hydrogenation to methanol. The CZC-G catalyst demonstrated exceptional methanol selectivity (96.8%) and a space-time yield of 73.6 g_MeOH·kg_cat^-1·h^-1 under optimized conditions. Long-term stability tests confirmed no obvious deactivation over 100 h of continuous operation. Structural and mechanistic analyses revealed that the urea-assisted grinding method promotes the formation of Cu/Zn-O_v-Ce ternary interfaces and inhibits the reduction of ZnO, enabling synergistic interactions for efficient CO₂ activation and selective stabilization of formate intermediates (HCOO*), which are critical for methanol synthesis. In-situ diffuse reflectance infrared Fourier transform spectra and X-ray absorption spectroscopy studies elucidated the reaction pathway dominated by the formate mechanism, while suppressing the reverse water-gas shift reaction. This work underscores the critical role of synthetic methodologies in engineering interfacial structures, offering a strategy for designing high-performance catalysts for sustainable CO₂ resource utilization.

Precise manipulation of the catalytic spin configuration and delineation of the relationship between spin related properties and oxidation pathways remain significant challenges in Fenton-like processes. Herein, encapsulated cobalt nanoparticles and cobalt-nitrogen-doped carbon moieties, endowed with confinement effects and variations in shell curvature were constructed via straightforward pyrolysis strategies, inducing alterations in magnetic anisotropy, electronic energy levels and spin polarization. The enhanced spin polarization at cobalt sites leads to a reduction in crystal field splitting energy and an increase in electronic spin density. This phenomenon facilitated electron transfer from cobalt orbitals to p_z orbitals of oxygen species within peroxymonosulfate molecules, thereby promoting the formation of high-valent cobalt species. The encapsulation effectively stabilized cobalt nanoparticles, mitigating their dissolution or deactivation during reactions, which in turn enhances stability and durability in continuous flow processes. The high-valent cobalt species within the shell exhibit increased exposure and generate localized high concentrations, thereby intensifying interactions with migrating pollutants and enabling efficient and selective oxidation of emerging compounds with elevated redox potentials. This work underscores the profound impact of confined encapsulation curvature and spin polarization characteristics of metal sites on catalytic oxidation pathways and performance, opening novel avenues for spin engineering in practical environmental catalysis.

The major challenge in photocatalytic water splitting lies in water oxidation reactions, which still suffer from poor charge separation. This study overcame inefficient charge separation by establishing a robust interfacial electric field through the electrostatic-driven assembly of Co₃O₄ nanoparticles with a perylene imide supramolecule (PDINH). The well-aligned band structures and intimate interfacial contact in the PDINH/Co₃O₄ heterostructure create an enhanced interfacial electric field that is 4.1- and 53.2-fold stronger than those of individual PDINH and Co₃O₄, thus promoting directional charge separation and transfer. Moreover, S-scheme charge transfer strongly preserves the oxidative holes in PDINH to drive efficient water oxidation reactions. Consequently, PDINH/Co₃O₄ composite achieves a photocatalytic oxygen evolution rate of 29.26 mmol g^-1 h^-1 under visible light irradiation, 8.2-fold improvement over pristine PDINH, with an apparent quantum yield of 6.66% at 420 nm. This study provides fundamental insights into interfacial electric field control for the development of high-performance organic photocatalysts for efficient water oxidation.

Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction (OER) in anion exchange membrane water electrolysis. Here, homogeneous high entropy oxide (HEO) film is in-situ fabricated on nickel foam (NF) substrate via magnetron sputtering technology without annealing process in air, which is composed of many spinel-structured (FeCoNiCrMo)₃O₄ grains with an average particle size of 2.5 nm. The resulting HEO film (abbreviated as (FeCoNiCrMo)₃O₄) exhibits a superior OER performance with a low OER overpotential of 216 mV at 10 mA cm^-2 and steadily operates at 100 mA cm^-2 for 200 h with a decay of only 272 μV h^-1, which is far better than that of commercial IrO₂ catalyst (290 mV, 1090 μV h^-1). Tetramethylammonium cation (TMA⁺) probe experiment, activation energy analysis and theoretical calculations unveil that the OER on (FeCoNiCrMo)₃O₄ follows an adsorbate evolution mechanism pathway, where the energy barrier of rate-determining step for OER on (FeCoNiCrMo)₃O₄ is substantially lowered. Also, methanol molecular probe experiment suggests that a weakened *OH bonding on the (FeCoNiCrMo)₃O₄ surface and a rapid deprotonation of *OH, further enhancing its OER performance. This work provides a feasible solution for designing efficient high entropy oxides electrocatalysts for OER, accelerating the practical process of water electrolysis for H₂ production.

Electrochemical nitrate reduction (eNO₃RR) and nitric oxide reduction (eNORR) to ammonia have emerged as promising and sustainable alternatives to the traditional Haber-Bosch method for ammonia production, particularly within the recently proposed reverse artificial nitrogen cycle route: N₂ → NO_x → NH₃. Notably, experimental studies have demonstrated that eNORR exhibits superior performance over eNO₃RR on Cu₆Sn₅ catalysts. However, the fundamental mechanisms underlying this difference remain poorly understood. Herein, we performed systematic theoretical calculations to explore the reaction pathways, electronic structure effects, and potential-dependent Faradic efficiency associated with ammonia production via these two distinct electrochemical pathways (eNORR and eNO₃RR) on Cu₆Sn₅. By implementing an advanced ‘adaptive electric field controlled constant potential (EFC-CP)’ methodology combined with microkinetic modeling, we successfully reproduced the experimental observations and identified the key factors affecting ammonia production in both reaction pathways. It was found that eNORR outperforms eNO₃RR because it circumvents the ^*NO₂ dissociation and ^*NO₂ desorption steps, leading to distinct surface coverage of key intermediates between the two pathways. Furthermore, the reaction rates were found to exhibit a pronounced dependence on the surface coverage of ^*NO in eNORR and ^*NO₂ in eNO₃RR. Specifically, the facile desorption of ^*NO₂ on the Cu₆Sn₅ surface in eNO₃RR limits the attainable surface coverage of ^*NO, thereby impeding its performance. In contrast, the eNORR can maintain a high surface coverage of adsorbed ^*NO species, contributing to its enhanced ammonia production performance. These fundamental insights provide valuable guidance for the rational design of catalysts and the optimization of reaction routes, facilitating the development of more efficient, sustainable, and scalable techniques for ammonia production.

Single-metal sites anchored in nitrogen-doped nanocarbons are recognized as potent electrocatalysts for applications in energy conversion and storage. Here, an innovative inorganic salt-mediated secondary calcination strategy was developed to construct robust Pt single-atom catalysts on nitrogen- and oxygen-doped graphene nanosheets (Pt-N/O-GNs), thereby significantly enhancing the efficiency of the electrocatalytic oxygen reduction reaction (ORR). The ultrathin N/O-GNs, obtained by stripping Zn-ZIF with auxiliaries of KCl and LiCl, provide stable anchoring sites for highly exposed Pt-N₃O active structures. The Pt-N/O-GNs catalyst, featuring a low Pt loading of 0.44 wt%, demonstrates exceptional mass activity in the ORR process. It attains an impressive onset potential of 0.99 V and a half-wave potential of 0.88 V. The zinc-air battery driven by the Pt-N/O-GNs displays superior power density and cycle stability. Theoretical computational studies reveal that the structure of heteroatoms doped in few-layer graphene facilitates the stable anchoring of single-atom configurations. The findings provide new perspectives for the tailored design and fabrication of single-metal-site electrocatalysts.

Elemental doping of BiVO₄ crystal lattices effectively enhances carrier separation, thereby facilitating efficient photoelectrochemical water splitting. However, the positive effect of elementally induced lattice distortions on hole extraction has been neglected. Herein, the crystal lattice of BiVO₄ is distorted by doping with an inexpensive Cs metal; then, CoFe₂O₄ is used as an efficient hole-extraction layer to further modify the surface of the doped photoanode. Benefiting from the above design, the newly prepared CoFe₂O₄-Cs-BiVO₄ photoanode achieved a photocurrent density of 5.66 mA cm^-2 at 1.23 V vs. a reversible hydrogen electrode, indicating a 3.9-fold improvement in photocurrent density. Detailed physicochemical characterization and density functional theory calculations showed that the lattice distortion induced by Cs doping promoted the directional migration of BiVO₄ bulk-phase holes to the CoFe₂O₄ layer. Additionally, the coupled CoFe₂O₄ can be used as a hole extraction layer to further enhance the interfacial migration of carriers. The synergistic effect of the two effectively promotes the directional migration of photogenerated carriers from the BiVO₄ bulk phase to the active sites of the oxygen evolution reaction, thereby effectively inhibiting carrier recombination. This study revealed the positive effect of the dual-hole extraction strategy on solar energy conversion, thereby opening new avenues for the rational design of photoanodes.