Heterostructure Electrocatalyst Research Articles

Revolutionizing water oxidation: NiSe/NiO heterostructure as a high-performing oxygen evolution reaction catalyst

The sluggish kinetics of electrolysis of water is the major challenge which hampers the practical dissociation of water in H2 and O2 gas. Electrocatalysts are particularly required to enhance the performance of the water splitting process. In this manuscript, the catalytic performance of nickel selenide/nickel oxide (NiSe/NiO) heterostructure and its counter parts are bestowed for water splitting. The formation of synthesized materials along with phase structure were characterized by the XRD and the SEM was used for surface morphology. Among reported electrocatalysts, NiSe/NiO heterostructure has emerged as the best electrocatalyst for OER. It commences oxygen evolution at 1.34 V with minimum overpotential of 110 mV even at 20 mA/cm2. Chronoamperometry reveals excellent electrochemical stability for the extended period of 21 h for heterostructure electrocatalyst. The kinetic study has recommended NiSe/NiO as an adequate electrocatalyst for OER having Tafel slope of 43.56 mV/dec. These results surpass benchmark precious metal based electrocatalysts as well as electrocatalysts based on Ni. This development dispenses earth abundant, exceedingly efficient and extremely stable, non-precious metal based electrocatalysts for practical electrolysis of water.

Interfacial engineering of Ni/WC heterostructure electrocatalyst for highly efficient hydrogen evolution reaction in all pH electrolyte

The development of high-performance electrocatalyst for sustainable hydrogen production is a necessary prerequisite for rapid progress of hydrogen economy. The integration of multi-interfaces in binary-component heterostructures for robust HER electrocatalysts has been proved to be a feasible strategy for optimizing the electronic structure and H adsorption/desorption of active sites and facilitate their HER kinetic. Herein, a series of N-doped carbon coated binary-phase Ni/WC heterostructure (Ni/WC@C) were prepared by annealing a mixture of Ni-substituted POMs with serial atomic ratio of Ni:W (2:3, 4:9 and 1:11) and dicyandiamide. By virtue of abundant and homogeneously distributed dual-phase Ni/WC interface with high intrinsic activity, Ni4W9@C originated from the precursor with Ni:W atomic ratio of 4:9 delivers ultralow overpotential of 38 mV to reach the current density of 10 mA cm−2 and Tafel slope of 43 mV/dec in 0.5 M H2SO4 electrolyte. This prominent performance can be achieved in all-pH eletrolytes. By virtue of the ultra-stable Ni/WC interfaces and the wrapping effect in N-doped carbon shell, Ni4W9@C shows robust electrochemical durability and structural stability in all acidic, neutral, and alkaline media. This work provides a potentially powerful interface engineering strategy for the design and performance improvement of multi-component HER electrocatalysts.

Tuning the interface of MIMII(OH)F@MIMII1-xS (MⅠ: Ni, Co; MⅡ: Co, Fe) by atomic replacement strategy toward high performance overall water splitting

Constructing heterostructure is considered as one of the most promising strategies to reveal high efficiency hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance. Nevertheless, it is highly challenging to obtain stable interfaces and sufficient active sites via conventional method. In addition, Ni, Co and Fe elements share the valence electron structures of 3d6-84s2, the appropriate integration of these metals to induce synergistic effect in multicomponent electrocatalysts can enhance electrochemical activity. Herein, in this work, the MIMII(OH)F@MIMII1-xS (NiFe(OH)F@NiFe1-xS, NiCo(OH)F@NiCo1-xS, CoFe(OH)F@CoFe1-xS) autogenous heterostructure on nickel foam are constructed. As a result, NiFe(OH)F@NiFe1-xS-0.05, NiCo(OH)F@NiCo1-xS-0.05, and CoFe(OH)F@CoFe1-xS-0.05 demonstrate outstanding overpotential for HER (70 mV, 90 mV, 81 mV at −10 mA cm−2) and OER (370 mV, 470 mV, 370 mV at 10 mA cm−2) in alkaline electrolyte, while the overpotential for HER is 176 mV, 189 mV, 167 mV at −10 mA cm−2 and corresponding OER is 290 mV, 390 mV, 300 mV at 10 mA cm−2 in simulated seawater, respectively. In addition, the NiFe, NiCo, CoFe-based electrolyzer acquire favorable overall water splitting activity in alkaline (1.72 V, 1.87 V, 1.66 V) and simulated seawater (1.73 V, 1.75 V, 1.69 V) at 10 mA cm−2. Overall, the above results authenticate the feasibility of developing autogenous heterostructure electrocatalysts for providing hydrogen and oxygen in alkaline and simulated seawater.

Modulating Electronic Structure by Etching Strategy to Construct NiSe2 /Ni0.85 Se Heterostructure for Urea-Assisted Hydrogen Evolution Reaction.

Exploring and developing novel strategies for constructing heterostructure electrocatalysts is still challenging for water electrolysis. Herein, a creative etching treatment strategy is adopted to construct NiSe2 /Ni0.85 Se heterostructure. The rich heterointerfaces between NiSe2 and Ni0.85 Se emerge strong electronic interaction, which easily induces the electron transfer from NiSe2 to Ni0.85 Se, and tunes the charge-state of NiSe2 and Ni0.85 Se. In the NiSe2 /Ni0.85 Se heterojunction nanomaterial, the higher charge-state Ni0.85 Se is capable of affording partial electrons to combine with hydrogen protons, inducing the rapid formation of H2 molecule. Accordingly, the lower charge-state NiSe2 in the NiSe2 /Ni0.85 Se heterojunction nanomaterial is more easily oxidized into high valence state Ni3+ during the oxygen evolution reaction (OER) process, which is beneficial to accelerate the mass/charge transferand enhancethe electrocatalytic activities towards OER. Theoretical calculations indicate that the heterointerfaces are conducive to modulating the electronic structure and optimizing the adsorption energy toward intermediate H* during the hydrogen evolution reaction (HER) process, leading to superior electrocatalytic activities. To expand the application of the NiSe2 /Ni0.85 Se-2h electrocatalyst, urea is served as the adjuvant to proceed with the energy-saving hydrogen production and pollutant degradation, and it is proven to be a brilliant strategy.

Hierarchical assembly of NiFe-PB-derived bimetallic phosphides on 3D Ti3C2 MXene ribbon networks for efficient oxygen evolution

The development of MXene-based heterostructures for electrocatalysis has garnered significant attention owing to their potential as high-performance catalysts that play a pivotal role in hydrogen energy. Herein, we present a multistep strategy for the synthesis of a Ti3C2 MXene ribbon/NiFePx @graphitic N-doped carbon (NC) heterostructure that enables the formation of three-dimensional (3D) Ti3C2 MXene ribbon networks and bimetallic phosphide nanoarrays. With the assistance of HF etching and KOH shearing, the MXene sheets were successfully transformed into 3D MXene networks with interlaced MXene ribbons. Notably, a hydrothermal method, ion exchange route, and phosphorization process were used to anchor NiFePx@NC nanocubes derived from Ni(OH)2/NiFe-based Prussian blue (NiFe-PB) onto the MXene ribbon network. The resulting MXene ribbon/NiFePx@NC heterostructure demonstrated enhanced oxygen evolution reaction (OER) activity, characterized by a low overpotential (164 mV at a current density of 10 mA cm−2) and a low Tafel slope (45 mV dec−1). At the same time, the MXene ribbons/NiFePx@NC heterostructure exhibited outstanding long-term stability, with a 12 mV potential decay after 5000 cyclic voltammetry (CV) cycles. This study provides a robust pathway for the design of efficient MXene-based heterostructured electrocatalysts for water splitting.

Interface engineering of NiS/NiCo2S4 heterostructure with charge redistribution for boosting overall water splitting

Developing highly efficient bifunctional non-noble metal-based electrocatalysts is pivotal to fulfilling practical water electrolysis. In this work, NiS/NiCo2S4 heterostructured electrocatalysts are prepared through a simply controlling sulfurization process by employing a one-pot solvothermal strategy. The alteration of cobalt addition amount can affect the crystalline phase, morphology, and catalytic activity of the resulting heterostructured materials. The successful integration of NiS with NiCo2S4 is realized by deliberately tuning the cobalt addition amount. The resulting Co-Ni-S5:1 delivers high activity with low overpotentials of 198 and 259 mV to attain 10 mA cm−2 when used as electrocatalysts toward hydrogen evolution reaction and oxygen evolution reaction, respectively. Experimental and theoretical calculations evidence the strong interface coupling between NiS and NiCo2S4 leads to increased electronic conductivity, electron migration near lattice-matched interface and interfacial charge redistribution, thereof enhancing the reaction kinetics rate and activity. Moreover, the potential application is demonstrated by employing Co-Ni-S5:1 in a two-electrode electrolyzer which can efficiently catalyze water electrolysis and work stably for 100 h. This work not only provides highly efficient bifunctional heterostructured electrocatalysts by simply regulating the metal components in sulfides but also further broadens the application of interface engineering.

Ferrum-doped nickel selenide @tri-nickel diselenide heterostructure electrocatalysts with efficient and stable water splitting for hydrogen and oxygen production

Ferrum-doped nickel selenide @tri-nickel diselenide heterostructure electrocatalysts with efficient and stable water splitting for hydrogen and oxygen production

Synergistic Active Phases of Transition Metal Oxide Heterostructures for Highly Efficient Ammonia Electrosynthesis

AbstractElectrochemically converting waste nitrate (NO3−) into ammonia (NH3) is a green route for both wastewater treatment and high‐value‐added ammonia generation. However, the NO3−‐to‐NH3 reaction involves multistep electron transfer and complex intermediates, making it a grand challenge to drive efficient NO3− electroreduction with high NH3 selectivity. Herein, an in‐operando electrochemically synthesized Cu2O/NiO heterostructure electrocatalyst is proven for efficient NH3 electrosynthesis. In situ Raman spectroscopy reveals that the obtained Cu2O/NiO, induced by the electrochemistry‐driven phase conversion, is the real active phase. This electronically coupled phase can modulate the interfacial charge distribution, dramatically lower the overpotential in the rate‐determining step and thus requiring lower energy input to proceed with the NH3 electrosynthesis. The orbital hybridization calculations further identify that Cu2O is beneficial for NO3− adsorption, and NiO could promote the desorption of NH3, forming an excellent tandem electrocatalyst. Such a tandem system leads to NH3 Faradaic efficiency of 95.6%, a super‐high NH3 selectivity of 88.5% at −0.2 V versus RHE, surpassing most of the NH3 electrosynthesis catalysts at an ultralow reaction voltage.

Embedding Co6Mo6C2-Mo2C heterostructure nanoparticles in carbon nanofibers as highly efficient electrocatalysts for overall water splitting

In this study, carbon nanofibers (CNFs) embedding molybdenum carbide (Mo2C)/cobalt (Co)-molybdenum (Mo) bimetallic carbide heterostructure electrocatalysts (denoted as A-B/CNFs) were prepared via electrospinning and high-temperature carbonization. Owing to the synergistic interaction between Co6Mo6C2 and Mo2C components, the catalyst activity is improved. Furthermore, the rich mesoporous structure and electrical conductivity of CNFs, accelerate the reaction kinetics. As a result, the optimized Co6Mo6C2-Mo2C/CNFs-1 has excellent bifunctional electrocatalytic activity. With the current density of 10 mA cm−2, the hydrogen evolution reaction (HER) overpotential is only 94 mV, and the oxygen evolution reaction (OER) overpotential is 295 mV in an alkaline electrolyte. Building an alkaline electrolyzer with Co6Mo6C2-Mo2C/CNFs-1 as the anode and cathode electrodes requires a low cell voltage of only 1.66 V to achieve the current density of 10 mA cm−2, while maintaining ideal durability. This research offers a versatile and effective approach to creating bimetallic-based monolithic hydrolysis electrocatalysts.

Construction of Ni4Mo/MoO2 heterostructure on oxygen vacancy enriched NiMoO4 nanorods as an efficient bifunctional electrocatalyst for overall water splitting

Despite great efforts over the past decade, rational design of bifunctional electrocatalysts with low cost and high efficiency still remains a challenge to achieve industrial water splitting. Herein, we synthesized the nickel-molybdenum nanorod array catalyst supported on NF (NMO@NM/MO) by a two-step process of hydrothermal and reductive annealing. Partial reduction of the NiMoO4 induces the structural reconstruction and formation of the Ni4Mo/MoO2 heterostructure on oxygen vacancy enriched nanorod, which bring out sufficient active sites, large specific surface area and favorable interfacial charge transfer. Thanks to the unique core–shell structure with the heterostructured Ni4Mo/MoO2 surface and defect-rich NiMoO4 core, the obtained electrocatalyst shows greatly improved hydrogen evolution reaction (HER) activity with an ultralow overpotential of 63 mV at 100 mA cm−2 (vs. 314 mV for the NiMoO4). Density function theory calculations reveal that the construction of the Ni4Mo/MoO2 heterostructure effectively accelerates H2O dissociation kinetics, while the defective NiMoO4 facilitates H* adsorption/desorption. Moreover, the heterostructure catalyst also displays excellent oxygen evolution reaction (OER) performance with the low overpotential of 274 mV at 100 mA cm−2. When coupling HER and OER by using NMO@NM/MO as both the cathode and anode, the alkaline electrolyzer delivers a current density of 10 mA cm−2 at only 1.50 V as well as good robustness. The synergistic effect of the hetero-interface and the defect engineering endows the electrocatalyst with excellent bifunctional catalytic activity for HER and OER. This work may provide a route for rational design of heterostructure electrocatalysts with multiple active components.

Construction of 3D Ni3Se2@NiCo-LDH heterostructured system for efficient electrocatalytic oxygen evolution reaction

Heterointerface engineering is an effective technique for synthesizing highly efficient catalysts that may synergize the advantages of each component to enhance their catalytic activity. This study developed a heterostructured Ni3Se2 @NiCo-LDH system, in which NiCo-LDH nanosheets are electrodeposited on hydrothermally-grown pine tree-like Ni3Se2 structures. The Ni3Se2 @NiCo-LDH heterostructured electrode exhibits a remarkably low overpotential (140 mV) for oxygen evolution reaction (OER) activity at a current density of 10 mA/cm2, which was attributed to the enhanced electrochemical properties of the interface owing to the high conductivity of Ni3Se2 and the high intrinsic OER activity of NiCo-LDH. In addition, the unusual pine tree-branched Ni3Se2 structure with NiCo-LDH nanosheets enabled the generation of additional active sites at the heterointerface, which exhibited enhanced oxygen evolution capability, with a strong electron connection from Ni and Co and an active synergistic contribution from selenide. Additionally, after 20 h of electrolysis in 1.0 M KOH, the catalyst maintained 98.8 % of its initial current density. The findings of this study is expected to set the path for the production of further heterostructure electrocatalysts.

In-situ construction of Mo2C–MoC heterostructure on Ni foam for efficient hydrogen evolution in alkaline media

Herein, a composite Mo2C–MoC heterostructured electrocatalyst is directly grown on Ni foam (NF) via the simple one-step annealing of MoCl5, urea, and NF under a flow of N2 at various temperatures for use in the hydrogen evolution reaction (HER). In the proposed synthetic method, the ratio of Mo2+ and Mo3+ in the Mo2C–MoC heterostructure, along with the HER performance, is greatly affected by the annealing temperature. In particular, the Mo2C–MoC/NF catalyst prepared at 650 °C exhibits a superior HER performance, with small overpotentials of 28.6 and 119.7 mV at 10 and 100 mA cm−2, respectively, along with great stability for 50 h in 1 M KOH. Notably, this is among the best performance results for recently reported molybdenum carbide-based catalysts. This is attributed to the interplay between the Mo2C–MoC heterostructure and the NF, whereby the former provides active sites by optimizing the hydrogen binding energy, while the latter provides a large surface area and high electrical conductivity.

Photo-sensitive CuS/NiO heterostructure electrocatalysts for energy-saving hydrogen evolution reaction at all pH conditions

Heterostructures based on transition metal chalcogenides/oxides have gained significant interest in the application of electrochemical hydrogen evolution reaction (HER) due to their distinct characteristics and excellent electrocatalytic activity. Herein, we developed an earth-abundant, low-cost, and light-sensitive CuS/NiO (CSNO) heterostructure electrocatalyst via a facile co-precipitation method and fabricated it on silver-modified conducting cellulose paper for HER. Under all pH level, the performance of the visible light-sensitive HER catalyst has been examined. With the illumination of light, HER performance at all pH, which conserves energy has been seen. In basic media, the value of overpotential was improved to −290 mV vs RHE at 20 mA/cm2 under light-illuminating conditions. Similarly, with light illumination, the overpotential of the CSNO10/Ag- modified paper is reduced to −363 mV and −312 mV vs RHE in an acidic and in a near-neutral medium, respectively. In addition to that, the values of the Tafel slopes and charge-transfer resistance also decreased indicating relatively faster HER kinetics in the presence of light at all pH levels. Also, The CSNO10 electrode exhibits stability of more than 24 h in 1 M PBS with an overpotential of −368 mV vs RHE at 20 mA/cm2. The overall performance of the CuS/NiO heterostructure is a good sign to be explored it as a low-cost and efficient electrocatalyst for the large-scale production of green hydrogen (H2).

High Alkaline Electrochemical Hydrogen Evolution on a Pt/GaN Heterostructure

AbstractThe construction of suitable metal/substrate interfaces that can synergistically optimize the water dissociation, hydrogen transfer and hydrogen adsorption processes has proved to be a promising approach to boost the alkaline electrochemical hydrogen evolution reaction (HER) but remains challenging. Herein, a Pt/GaN heterostructure electrocatalyst is constructed using the electrochemical deposition technique and used for alkaline electrochemical HER. The as‐synthesized Pt/GaN catalyst exhibits competitive HER performance, including low overpotentials of 24 and 441 mV to reach current densities of 10 and 1000 mA cm−2, respectively, and a superior mass activity (7.34 A mgPt−1 at the overpotential of 100 mV), which is 25.7 and 5.0 times higher than commercial Pt/C and as‐synthesized Pt/CP, respectively. First‐principle calculations suggest that the Pt/GaN heterostructure can greatly reduce the energy barrier for H2O dissociation, create a local acid‐like microenvironment through a H spillover process and optimize the value of ΔGH, leading to a remarkable acceleration of the alkaline HER kinetics. This discovery provides new insights for the development of alkaline HER catalysts.

Metal-organic frameworks derived FeS2@CoS2 heterostructure for efficient and stable bifunctional electrocatalytic water splitting

The exploration of efficient metal-based bifunctional catalysts for electrochemical water splitting is a promising approach for large-scale applications. In this work, we constructed a FeS2@CoS2 heterostructure electrocatalyst by a facile solution-dipping and hydrothermal method. The optimum FeS2@CoS2 heterostructure showed notable oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performances, with overpotential values of 280 mV and 136 mV (10 mA cm−2 current density), respectively. Additionally, the electrocatalyst exhibited a robust stability performance of 50 h at a current density of 10 mA cm−2. The two-cell electrolyzer is assembled using FeS2@CoS2||FeS2@CoS2 and delivers a cell voltage of 1.62 V and 1.99 V at 10 and 50 mA cm−2 current densities with excellent durability. The outstanding overall water-splitting activity of the obtained heterostructure can be attributed to effective electronic interactions, synergistic effects, and exposure of more reactive active sites in the electrocatalyst. This work presents a promising strategy for developing highly active and cost-effective metal sulfide-based bifunctional electrocatalysts for energy conversion technology.

Three-phase-boundary Pt in a self-supported MoPt2-MoNi4/Mo2C heterojunction electrocatalyst for highly efficient pH-universal hydrogen evolution reaction

Design of high-performance Pt-based electrocatalysts is significant for hydrogen production through water splitting at pH-universal conditions but still challenging. Herein, the MoPt2-MoNi4/Mo2C three-phase heterojunction is fabricated via simply pyrolyzing hydrothermally resultant Mo-Ni precursor with subsequent galvanic Pt replacement process. It exhibits remarkable and stable hydrogen evolution reaction (HER) performance with impressive mass activity and low overpotential of 53, 77 and 46 mV at the current density of 100 mA cm−2 in alkaline, neutral and acidic media, respectively. Density functional theory calculations illustrate that there are multiple types of Pt sites in the phase of MoPt2 in such three-phase heterojunction, while only the Pt atoms located in the three-phase boundary not only process optimal electronic structure modulated by MoNi4/Mo2C, but also act as highly-active sites for HER. Moreover, downshifted d-band center of Pt triggered by the construction of three-phase MoPt2-MoNi4/Mo2C heterojunction, which regulating the free energy of reactive intermediates sorption and thereby accelerating the entire HER process. This work provides some constructive suggestions to design highly efficient Pt-based heterostructured electrocatalysts towards HER.

Interface and doping engineering of Co-based electrocatalysts for enhanced oxygen reduction and evolution reactions

The fabrication of highly efficient bifunctional catalyst for oxygen evolution/reduction reaction (OER/ORR) is essential for high performance rechargeable Zn-air batteries. Herein, we present a method of simultaneous interface/doping engineering to prepare bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries. The Fe-Co2P/Co heterostructure was covered by N-doped carbon boxes (Fe-Co2P/Co@NC), and the surface electronic structure of Fe-Co2P/Co@NC was tailored through the controlled co-doping of P and Fe. Theoretical calculation revealed a significant charge accumulation at the interface of Fe-Co2P and Co, demonstrating a strong synergy in Fe-Co2P/Co@NC catalyst. The as-prepared Fe-Co2P/Co@NC catalyst exhibited an excellent catalytic performance for ORR/OER as well as rechargeable Zn-air batteries with large power density (783 mA h gZn−1), high open circuit voltage (1.54 V) and long charge/discharge stability (155 h). This work provides a new approach for the construction of interface-rich heterostructure electrocatalysts for oxygen catalysis.

Highly selective conversion of CO2 to formate on SnOx/GDY heterostructured electrocatalyst

An important step in the efficient production of formate (HCOO-) from CO2 and water is the development of electrocatalysts with high selectivity, activity at large current densities. Here we report a new heterostructure electrocatalyst which demonstrate highly selective CO2 reduction reaction by selective growth of polycrystalline Tin oxides on the graphdiyne. Our results show the natural advantages of GDY in effectively regulating the valence states of Sn and phase structure transition of the catalyst, and increasing charge transfer capacity and number of active sites, resulting in excellent catalytic performance. The electrocatalyst can selectively and efficiently produce and stabilize the key *OCHO intermediates and promote the formation of formate by completely inhibiting the competing HER, greatly promoting CO2RR. The electrocatalyst shows superior CO2-to-formate conversion performance at ambient temperatures and pressures with a highest reaction selectivity of 99.5% and a high formate yield rate of 323.42 μmol h−1 cm−2 in a large current density of 112 mA cm−2 at a low applied potential of − 0.9 V versus RHE.

Simple construction of NiCo-LDH@FeOOH nanoflower heterostructure by chemical etching strategy for efficient oxygen evolution reaction

The large overpotential and slow kinetics of the oxygen evolution reaction (OER) on an anode seriously reduces the water splitting efficiency. Herein, the FeOOH decorated NiCo-layered double hydroxides (NiCo-LDH@FeOOH) nanoflower heterostructure electrocatalyst is synthesized using a simple one-step ZIF-67 derivation and chemical etching strategy. Owing to the unique 3D heterogeneous nanoflowers structure formed by etching, the strong interface interaction regulates the electronic structure, and combined with the synergistic effect between the three metals, the electrochemical activity of the catalyst is significantly increased. NiCo-LDH@FeOOH exhibits superior OER activity with a low overpotential of 255 mV at a current density of 50 mA cm–2 under alkaline conditions and provides long-term durability (73 h). Moreover, experiments and density functional theory calculations reveal that the Co-site synergistically promote the OER activity of the Fe site. This study sheds new light on constructing LDH-based heterogeneous composite electrocatalysts.

Synergistic Ru/CeO2 heterostructure for alkaline hydrogen oxidation with high activity and CO tolerance

The lack of highly efficient and stable electrocatalysts for anodic hydrogen oxidation reaction (HOR) has limited the large-scale industrial application of alkaline exchange membrane fuel cell. In this work, a Pt-free Ru/CeO2 heterostructure electrocatalyst with outstanding catalytic activity and stability for alkaline HOR is developed. The synthesized Ru/CeO2 with synergistic heterogeneous interface exhibits a high kinetic current density reaching 21.7 mA cm−2 at an overportentail of 50 mV, which is nearly 11-fold higher than that of the contrastive Ru/C catalyst and almost the same as that of commercial Pt/C catalyst. Importantly, this electrocatalyst also shows high CO resistance that Pt/C catalyst lacks. Electrochemical results and spectral studies show that CeO2 not only efficiently adjusts the electronic microenvironment of Ru site to promote Had adsorption, but also provides the adsorption sites for OHad at a low potential. As a result, the introduced CeO2 synergistically promotes hydrogen oxidation, H2O formation and CO removing, thereby enhancing the HOR performance of Ru nanoclusters.