Catalytic Performance Research Articles

Progress in 2D MoS2-Based Advanced Materials for Hydrogen Evolution and Energy Storage Applications

The increasing energy demand for and fast depletion of fossil fuels have driven the need to explore renewable and clean energy sources. Hydrogen production via water electrocatalysis is considered a promising green fuel technology for addressing global energy and environmental challenges while supporting sustainable development. Molybdenum disulfide (MoS2) has emerged as a potential electrocatalyst for hydrogen evolution reactions (HERs) and super-capacitor (SC) applications due to its high electrochemical activity, low cost, and abundance. However, compared to noble metals like platinum (Pt), MoS2 exhibit lower HER activity in water electrocatalysis. Therefore, further modification is needed to enhance its catalytic performance. To address this, MoS2 has been effectively modified with materials such as reduced graphene oxide (rGO), carbon nanotubes (CNTs), polymers, metal oxides, and MXenes. These modifications significantly improve the electrochemical properties of MoS2, enhancing its performance in HER and SC applications. In this review article, we have compiled recent reports on the fabrication of MoS2-based hybrid materials for HER and SC applications. The challenges, advantages, and future perspectives of MoS2-based materials for HERs and SCs have been discussed. It is believed that readers may benefit from the recent updates on the fabrication of MoS2-based hybrid materials for HER and SC applications.

One‐step Synthesis, Characterization and Ammonia‐selective Catalytic Reduction Performance of Cu‐SAPO‐34 Catalyst

The Cu‐SAPO‐34 catalyst, a promising selective catalytic reduction (SCR) catalyst for the denitration of mobile sources, has attracted widespread research interest due to its wide temperature window, remarkable catalytic performance and good stability and. In this study, a series of Cu‐SAPO‐34 catalysts with varying Cu contents were synthesized by the one‐step hydrothermal method. The physicochemical properties of the catalysts were investigated by characterizations, and the reasons for the well‐activity catalysts were analyzed. The acidic sites on the SAPO‐34 zeolite can adsorb and activate NH3, while the copper active sites can promote the activation and reduction of NOx, accelerating the reaction process of SCR. In this study, Cu‐SAPO‐34 with Cu content of n(Cu)/n(C9H21AlO3) = 0.075 has good framework stability, which produced more free Cu2+ ions and the Cu species are evenly distributed on the carrier surface, and the appropriate amount of acid sites. Therefore, the Cu0.075‐SAPO‐34 catalyst exhibits the highest NO conversion performance, maintaining a NO conversion rate above 90% within the temperature range of 165‐450 °C.

Synergistic effect of ZnO-ZnFe2O4 heterostructures for enhanced surface catalytic activity in Cr(VI) reduction, green H2 generation and CO sensing: an experimental study supported by DFT.

Increasing energy demand is an indication of progress, but it necessitates careful management of environmental pollution for maintaining a healthy life and ensuring a better planet for future generations. Heterostructure material-based catalysts have emerged as a comprehensive solution to combat the diverse challenges related to energy and environment. Herein, an n-n-type ZnO-ZnFe2O4 heterostructure was synthesized via a simple reflux followed by a co-precipitation technique for the same. Detailed photocatalytic and gas sensing studies revealed that a 50% ZnO-50% ZnFe2O4-based sample (ZZF-11) showed the highest Cr(VI) degradation with a rate constant of ∼159 × 10-4 s-1, which was ∼23 times higher than that of pristine ZnO and 6.4 times higher than that of pristine ZnFe2O4. Additionally, the ZZF-11 sample produced ∼550 μmol g-1 of H2 within a 300 minute interval via a photocatalytic water-splitting reaction. The ZZF-11 sensor also showed a significantly high response to 1 ppm CO gas (S = 29.4%) compared to all other pure and composite samples. The formation of the heterostructure and transfer of charges through the interface played an important role here. The most possible mechanism for the enhanced surface catalytic performance of ZZF-11 was critically analysed by corroborating the experimental results with DFT results. This study demonstrates a unified pathway to enhance the various surface catalytic processes by tuning different parameters of the heterostructure material to simultaneously overcome environment- and energy-related issues.

Illuminating the Future: Sunlight-Powered Catalysis Unlocks Next-Generation Li-O2 Battery Performance.

Lithium-oxygen (Li-O2) batteries have an extremely high theoretical specific energy but are hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Visible-light-assisted photocatalysts can accelerate OER kinetics. However, the photoinvolved electrochemical process at the oxygen cathode remains insufficiently understood, and the interlaboratory results are not comparable and reproducible. In fact, sunlight or a xenon lamp as the light source induces a notable photothermal effect in the batteries, while its impact on reaction kinetics is always underappreciated. Here, a self-illuminating photocatalyst composed of g-C3N4 catalysts and Sr2MgSi2O7:Eu,Dy phosphors is designed to decouple the photo and thermal effects on the reaction kinetics. Typically, the photocatalytic effects dominate at low external illumination powers, while the photothermal effects increase linearly with power. This work provides a quantitative basis for benchmarking the catalytic performance of various photocatalysts. Moreover, as a proof of concept, this study offers new insights for developing integrated photoassisted Li-O2 batteries.

Revealing the origin of activity and selectivity in nitrate to ammonia conversion on single transition metal atom catalysts supported by a Ti2NO2 monolayer.

In recent years, the issue of nitrate (NO3-) contamination has become an increasingly severe problem for human life. Electrocatalytic nitrate reduction to ammonia (NH3) is one of the promising strategies to eliminate nitrate contamination. However, the reduction of NO3- to NH3 is a multi-electron process and is susceptible to interference from by-products and competing hydrogen evolution reactions (HER). Introducing a single transition metal (TM) atom onto MXene-based surfaces can alter MXenes' electronic configuration, enhancing their catalytic performance and the Faraday efficiency of the nitrate reduction reaction (NO3RR). In this work, we investigated the initial activation mechanisms of nitrate on various TM-modified Ti2NO2 (TM@Ti2NO2) catalysts and their NO3RR performance using first-principles calculations, aiming to select effective NO3RR electrocatalysts. The results indicated that both V@Ti2NO2 and Cr@Ti2NO2 were viable catalysts for NO3RR, showing particular promise for the efficient conversion of NO3- to NH3 at the most favorable limiting potentials of -0.41 V and -0.52 V, respectively. Further electronic structure analysis (density of states, COHP, and the descriptor ψ) confirmed that the single TM atom supported the boost in product selectivity and efficiency of NH3 by acting as an electron "bridge" to strengthen the interaction between NO3- and MXenes. AIMD simulations indicated that V@Ti2NO2 and Cr@Ti2NO2 maintained dynamical stability at the reaction temperature. These findings lay the foundation for a deeper understanding of the initial activation mechanisms and provide fresh theoretical insights into the design of MXene-based electrocatalysts with high NO3RR performance.

Machine Learning Speeds Up the Discovery of Efficient Porphyrinoid Electrocatalysts for Ammonia Synthesis

Two‐dimensional transition metal porphyrinoid materials (2DTMPoidMats), due to their unique electronic structure and tunable metal active sites, have the potential to enhance interactions with nitrogen molecules and promote the protonation process, making them promising electrochemical nitrogen reduction reaction (eNRR) electrocatalysts. Experimentally screening a large number of catalysts for eNRR catalytic performance would consume considerable time and economic resources. First‐principles calculations and machine learning (ML) algorithms could greatly improve the efficiency of catalyst screening. Using this approach, we selected 86 candidates capable of catalyzing eNRR from 1290 types of 2DTMPoidMats, and verified the results with density functional theory (DFT) computations. Analysis of the full reaction pathway shows that MoPp‐meso‐F‐β‐Py, MoPp‐β‐Cl‐meso‐Diyne, MoPp‐meso‐Ethinyl, and WPp‐β‐Pz exhibit the best catalytic performance with the onset potential of −0.22, −0.19, −0.23, and −0.35 V, respectively. This work provides valuable insights into efficient design and screening of eNRR catalysts and promotes the application of ML algorithmic models in the field of catalysis.

Protonation of Nitrogen-Containing Covalent Organic Frameworks for Enhanced Catalysis.

Covalent organic frameworks (COFs) are a class of porous crystalline materials with ordered structures and tunable properties, which have been widely explored in catalysis, sensing, gas storage, and separation. Among various post-synthetic modifications, protonation emerges as a simple yet effective strategy to fine-tune the properties of nitrogen-containing COFs, thereby enhancing their catalytic performance. This concept article highlights the contribution of protonation on the mass transfer kinetics, charge distribution, photo-response, charge transfer, and other properties related to photocatalysis and electrocatalysis. The applications of protonated COFs are explored in catalytic processes including hydrogen evolution, CO2 reduction, H2O2 synthesis, and singlet oxygen generation. We also emphasize the necessity of considering the protonation process when nitrogen-containing COFs are applied in acidic environments to accurately reveal the structure-activity relationship. By analyzing recent advancements in protonated COFs, this article underscores the potential and challenges of protonation as a powerful tool for advancing COF-based catalytic systems.

Evolution and Reconstruction of Air-Electrode Surface Composition in Reversible Protonic Ceramic Cells: Mechanisms, Impacts on Catalytic Performance, and Optimization Strategies - A Review.

Reversible protonic ceramic cells (R-PCCs) are at the forefront of electrochemical conversion devices, capable of reversibly and efficiently converting chemical energy into electricity at intermediate temperatures (350-700°C) with zero carbon emissions. However, slow surface catalytic reactions at the air-electrode often hinder their performance and durability. The electrode surface is not merely an extension of the bulk structure, equilibrium reconstruction can lead to significantly different crystal-plane terminations and morphologies, which are influenced by material's intrinsic properties and external reaction conditions. Understanding electrode surface evolution at elevated temperatures in water-containing, oxidative atmospheres presents significant importance. In this review, a comprehensive summary of recent processes in applying advanced characterization techniques for high-temperature electrode surfaces is provided, exploring the correlations between surface evolution and performance fluctuations by examining the structural evolution and reconstruction of various air-electrode surfaces associated with degradation and activation phenomena, offering insights into their impact on electrode performance. Furthermore, reported strategies and recent advances in enhancing the electrochemical performance of R-PCCs through engineering air-electrode surfaces is discussed. This review offers valuable insights into surface evolution in R-PCCs and is expected to guide future developments in high-temperature catalysis, solid-state ionics, and energy materials.

Enhanced the Catalytic Performance of Samarium and Cerium Co-Modified Mn-Based Oxide Catalyst for Soot Oxidation

Manganese-based oxides with good redox properties exhibit high soot oxidation activity. To further enhance their catalytic performance, introducing additional metal elements into manganese-based oxides is considered an effective approach. Herein, two rare earth elements (Sm and Ce)-modified MnOx catalysts were prepared by the co-precipitation method. The synthesized MnOx catalyst primarily consists of the Mn3O4 phase, with trace amounts of Mn5O8. The addition of Sm or Ce maintains the predominance of the Mn3O4 phase, increases the proportion of Mn5O8, and enhances the redox properties, thereby boosting the catalytic activity for NO and soot oxidation. Notably, the coexistence of Sm and Ce achieves optimal soot oxidation activity, with T10 reaching 306 °C. Comprehensive physicochemical characterization elucidates the underlying structure–performance relationships of these catalysts.

Insight into the Coupling of HgS and CuO with Metal-Organic Frameworks Support in Electrocatalytic Oxygen Evolution Reaction.

This study investigates the coupling of mercury sulfide (HgS) and copper oxide (CuO) nanoparticles with metal-organic frameworks (MOFs) as a support material for enhancing the electrocatalytic oxygen evolution reaction (OER). The integration of HgS and CuO into the MOF framework aims to leverage the unique electronic and structural properties of both the nanoparticles and the MOFs to improve catalytic performance. Metal-organic frameworks (MOFs), particularly ZIF-67, are investigated for their potential to catalyze water-splitting reactions due to their high porosity and large specific surface areas. The strategic incorporation of HgS and CuO into ZIF-67 significantly enhances its electrocatalytic properties, resulting in remarkable performance metrics: a low overpotential of 246 mV at 10 mA/cm2, a Tafel slope of 123 mV/dec, an expanded electrochemical active surface area (ECSA) of 23.56 cm2, and a reduced charge transfer resistance of 34.86 Ω. This integration enhances porosity and increases active surface area, which is crucial for improved catalytic performance. This investigation introduces an innovative methodology for fabricating highly efficient electrocatalysts, positioning HgS/CuO/ZIF-67 as a promising candidate for oxygen evolution reactions in alkaline media. The findings highlight the potential of this novel nanocomposite in future clean energy applications, particularly in the realm of water-splitting technologies.

Enantioselective Synthesis of Chiral Ferrocenyl Aminoalcohols: Simultaneous Induction of Multiple Types of Chirality by a Rhodium‐Catalyzed Asymmetric Ring‐Opening Strategy

Chiral ferrocenyl aminoalcohols were enantioselectively synthesized via the rhodium‐catalyzed asymmetric aminative ring‐ opening of 1,4‐epoxy‐1,4‐dihydronaphthalenylferrocenes. A planar chiral phosphine‐olefin ligand consisting of a cyclopentadienyl (Cp) manganese scaffold provided excellent catalytic performance, furnishing the ring‐opening products in high yield and enantioselctivity (up to 99:1 enantiomeric ratio (e.r.)). The enantioselectivity could be further improved by changing the steric congestion in the cyclopentadienyl unit of the ferrocenyl fragment of the starting 1,4‐epoxy‐1,4‐dihydronaphthalenylferrocene. Density functional theory (DFT) calculations confirmed the high enantioselective induction in the ring‐opening reaction, estimating an e.r. of 99:1, which is in excellent agreement with the experimental results. The application of the thus obtained chiral ferrocenyl aminoalcohols as ligands in asymmetric reactions was also investigated.

Dual-Defect Regulated G-C3N4 for Piezoelectric Catalytic Tumor Therapy with Enhanced Efficacy.

Piezoelectric catalysis for tumor treatment is an emerging method for generating reactive oxygen species (ROS). However, the development and optimization of piezoelectric catalytic nanomaterials remain the major challenge. Herein, by regulating the internal and surface defects of graphene phase carbon nitride (defect-engineered g-C3N4), its piezoelectricity and sonocatalytic performance is enhanced, thus achieving efficient tumor treatment. By reducing bulk defects, the charges excited by ultrasound (US) within the defect-engineered g-C3N4 can migrate more rapidly to the material surface, thereby enhancing their participation in redox reactions. Increasing surface defects not only introduce more active sites on the surface of defect-engineered g-C3N4 but also enhance the asymmetry of the defect-engineered g-C3N4 structure, resulting in excellent piezoelectric properties. This defect-engineered g-C3N4 nanosheet can effectively generate ROS in tumor cells and induce tumor cell apoptosis under US stimulation. This work not only introduces a method to enhance the piezoelectric catalytic performance of g-C3N4 but also expands the potential application of defect-engineered piezoelectric materials to tumor treatment.

Effect of P doped bimetallic FeCo catalysts on carbon matrix for oxygen reduction in alkaline media

ABSTRACT Catalysts’ redox reactions are crucial for storage and energy conversion. Therefore, the fabrication of cost-effective, structurally rational, and multifunctional advanced catalytic materials continues to be a crucial task. In this study, we obtained P, Fe, and Co co-doped, nitrogen-rich carbon nanofibers by directly forming carbon nanotubes from metal-organic frameworks through electrospinning and pyrolysis. The P0.025-FeCo/C catalyst demonstrated outstanding ORR activity, including an ECSA of 1954.3 cm2, a limited current density of -3.98 mA/cm2, an E1/2 of ~0.84 V, and an Eonset of ~0.94 V. After 5000 cycles, the P0.025-FeCo/C catalyst demonstrated remarkable enduring stability. These function enhancements occurred because of the electronic coupling between the metal and phosphorus, which altered the electron distribution at the metal center and optimized its electronic structure, thereby improving catalytic activity and stability. It exhibits good chemical stability in alkaline media and can maintain its catalytic performance for a long time, demonstrating good durability. Its tubular structure provides many active sites and superior electron transport paths owing to its unique channels and cavities, which help improve its activity and stability. Therefore, P0.025-FeCo/C is expected to become a non-precious metal catalyst for facilitating oxygen reduction reactions.

Enantioselective Synthesis of Chiral Ferrocenyl Aminoalcohols: Simultaneous Induction of Multiple Types of Chirality by a Rhodium-Catalyzed Asymmetric Ring-Opening Strategy.

Chiral ferrocenyl aminoalcoholswere enantioselectively synthesized via the rhodium-catalyzed asymmetric aminative ring- opening of 1,4-epoxy-1,4-dihydronaphthalenylferrocenes. A planar chiral phosphine-olefin ligand consisting ofacyclopentadienyl (Cp) manganese scaffoldprovided excellent catalytic performance, furnishing the ring-opening productsin high yield and enantioselctivity (up to 99:1 enantiomeric ratio (e.r.)). The enantioselectivity could be further improved by changing the steric congestion in the cyclopentadienyl unit of the ferrocenyl fragment ofthe starting1,4-epoxy-1,4-dihydronaphthalenylferrocene. Density functional theory (DFT) calculations confirmed the high enantioselective induction in the ring-opening reaction, estimating an e.r. of 99:1, which is in excellent agreement with the experimental results. The application of the thus obtained chiral ferrocenyl aminoalcoholsas ligands in asymmetric reactions was also investigated.

Zero-Valent Iron-Supported Magnetic Hydrochar Derived from Kitchen Waste for Efficient Fenton-like Degradation of Tetracycline Hydrochloride

In this study, hydrochars loaded with iron species (Fe@HTC and Fe@HTC−T) were prepared by chemical co-precipitation and tubular furnace sintering treatment to develop efficient and sustainable catalysts for antibiotic wastewater treatment, addressing key challenges in sustainable environmental management. The characterization results indicated that iron species loaded on the hydrochars changed from Fe3O4 to FeO and then to metallic Fe with the pyrolysis temperature increased from 400 °C to 800 °C. The results of the characterization revealed a phase transition of iron species, confirming the temperature-dependent evolution of catalytic activity. The catalytic performance of the hydrochar composites was evaluated for tetracycline hydrochloride (TC−HCl) degradation via a Fenton-like process. Under optimal conditions (0.2 g/L TC−HCl, 0.1 g/L catalyst, 0.1 mM H2O2, pH = 6.86), Fe@HTC−T demonstrated excellent catalytic activity with a removal efficiency of 91.2%. Moreover, Fe@HTC−T exhibited superior stability and low iron leaching rates, attributed to the protective role of the hydrochar matrix. Mechanism research suggested that hydroxyl radicals (•OH) played a dominant role in the degradation process. This study demonstrates the potential of utilizing low-cost and renewable hydrochar materials derived from biomass waste to address industrial challenges in treating high-concentration antibiotic wastewater, offering a sustainable and cost-effective solution with broad applications in environmental remediation.

Electron Beam Irradiation-Induced Defects Enhance Pt-TiO2 Photothermal Catalytic Degradation in PAEs: A Performance and Mechanism Study

Phthalic acid esters (PAEs), ubiquitous semi-volatile organic compounds (SVOCs) in indoor environments, pose adverse effects on human health. However, their degradation mechanisms and pathways remain unclear. Herein, we developed an efficient photothermal catalyst by introducing defects (oxygen vacancies, OVs) on TiO2 (P25) surfaces via electron beam irradiation technology with different irradiation doses (100, 300, 500, and 700 kGy). The TiO2 with defects was employed as a support to prepare Pt-TiO2 catalysts for the photothermal degradation of di (2-ethylhexyl) phthalate (DEMP) and dimethyl phthalate (DMP), two representative PAEs. TiO2 pre-treated with a 300 kGy irradiation dose supported the Pt catalyst (Pt-Ti-P-300) and presented the optimal catalytic performance for DEMP and DMP degradation. Characterization results confirmed that OVs were successfully introduced to the catalysts. Meanwhile, OVs induced by electron beam irradiation expanded the light absorption range and improved the generation and separation of photogenerated carriers, which significantly enhanced the catalytic activity of the catalysts for PAE degradation. Importantly, the degradation mechanism and pathway of DMP were further explored by using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and gas chromatography–mass spectrometry (GC-MS). These findings provide important insights into the electron beam irradiation-mediated regulation of catalysts and the photothermal catalytic removal of PAEs in indoor environments.

Improving the Methane Oxidation by Self‐Adaptive Optimization of Liquid‐Metal Catalysts

Methane, a major greenhouse gas and abundant carbon resource, presents significant challenges in catalysis due to its high symmetry and thermodynamic stability, which tend to cause over‐oxidation to CO2. Traditional catalysts require high temperatures and pressures to facilitate CH4 conversion, constrained by their rigid structures which lack the flexibility needed for optimizing complex reaction steps. This study introduces a novel Cu single atoms‐embedded liquid metal catalyst (Cu‐LMC) based on gallium alloys, characterized by dynamic, self‐adaptive structures that provide enhanced catalytic performance and selectivity. Our findings reveal that Cu‐LMC achieves a high methane conversion to methanol yield (5.9 mol·gCu‐1·h‐1) with a selectivity of 82%. The results show that mild surface oxidation significantly boosts the catalytic performance of Cu‐LMC by increasing active copper sites through the formation of a Cu‐O‐Ga configuration while preserving the catalyst's structural flexibility. In‐situ XPS and XAFS analyses, along with AIMD simulations, demonstrate that the Cu‐LMC enables self‐adaptive structural adjustments that lower methanol desorption energy and increase the energy barrier for by‐product formation, optimizing the overall methane conversion process. The results underscore the importance of designing catalysts with dynamic and adaptable structures to overcome traditional limitations and improve efficiency in catalytic reactions.

Improving the Methane Oxidation by Self-Adaptive Optimization of Liquid-Metal Catalysts.

Methane, a major greenhouse gas and abundant carbon resource, presents significant challenges in catalysis due to its high symmetry and thermodynamic stability, which tend to cause over-oxidation to CO2. Traditional catalysts require high temperatures and pressures to facilitate CH4 conversion, constrained by their rigid structures which lack the flexibility needed for optimizing complex reaction steps. This study introduces a novel Cu single atoms-embedded liquid metal catalyst (Cu-LMC) based on gallium alloys, characterized by dynamic, self-adaptive structures that provide enhanced catalytic performance and selectivity. Our findings reveal that Cu-LMC achieves a high methane conversion to methanol yield (5.9 mol·gCu-1·h-1) with a selectivity of 82%. The results show that mild surface oxidation significantly boosts the catalytic performance of Cu-LMC by increasing active copper sites through the formation of a Cu-O-Ga configuration while preserving the catalyst's structural flexibility. In-situ XPSand XAFSanalyses, along with AIMD simulations, demonstrate that the Cu-LMC enables self-adaptive structural adjustments that lower methanol desorption energy and increase the energy barrier for by-product formation, optimizing the overall methane conversion process. The results underscore the importance of designing catalysts with dynamic and adaptable structures to overcome traditional limitations and improve efficiency in catalytic reactions.

Tandem Oxidation-Condensation Tandem Catalysis via a Multifunctional Cu-Based Metal-Organic Framework.

The development of heterogeneous catalysts for tandem reactions remains a significant challenge for practical applications, primarily due to the need for multiple isolated catalytic sites. This study presents a novel metal-organic framework (MOF), Cu-AIPA, formulated as Cu(AIPA)(DMF)2 (AIPA: 2-amino isophthalic acid, DMF: N, N-dimethylformamide). The Cu-AIPA framework integrates three distinct catalytic mechanisms: redox activity, Brønsted basicity, and Lewis acidity. The structure of Cu-AIPA features redox-active Cu(II) centers and Brønsted basic sites, enabling the sequential transformation of alcohols to aldehydes and their subsequent condensation into imines. The close spatial arrangement of these redox-active/Lewis acidic and basic sites within the confined pores of Cu-AIPA facilitates efficient tandem catalysis. This process involves oxidizing benzyl alcohol to benzaldehyde using TEMPO without requiring an external base, followed by amine condensation. Compared with HKUST-1, another Cu-based MOF with a high surface area, Cu-AIPA demonstrated superior catalytic performance at room temperature. Recyclability tests revealed that Cu-AIPA retained over 90% conversion efficiency across at least three catalytic cycles. This study highlights the potential of MOFs incorporating multiple catalytic sites and confined pore structures for tandem reactions, emphasizing their potential for scalable and sustainable industrial applications.

Mitigating A-Site Segregation in Pyrochlore Oxides: Enhancing Oxygen Evolution Reaction Performance through Surface Engineering.

Significant progress has been achieved in enhancing the oxygen evolution reaction (OER) performance of pyrochloric oxides through geometric and electronic structure regulation. However, the issue of A-site cation segregation in these materials remains underexplored. In this study, Bi2Ru2O7, a promising OER electrocatalyst, is synthesized via a sol-gel method, and its surface is modified using l-ascorbic acid to address Bi3+ segregation. This treatment selectively removes the Bi2O3 passivation layer, inducing an amorphous RuOx layer that forms a heterostructure with crystalline Bi2Ru2O7. This engineered structure significantly enhances catalytic performance, reducing the overpotential to 259 mV at 10 mA cm-2 and maintaining stability after continuous operation for >30 h. Comprehensive characterization, electrochemical testing, and density functional theory calculations reveal that the improvements stem from an increased number of oxygen vacancies and enhanced electron transfer. This work underscores the importance of surface engineering to mitigate A-site segregation, providing a new strategy for optimizing Ru-based pyrochlores in energy conversion technologies.