CuCo Hybrid Oxides as Bifunctional Electrocatalyst for Efficient Water Splitting

Abstract

Solar-driven water splitting is a promising approach for renewable energy, where the development of efficient and stable bifunctional electrocatalysts for simultaneously producing hydrogen and oxygen is still challenging. Herein, combined with the hydrogen evolution reaction (HER) activity of a copper(I) complex and oxygen evolution reaction (OER) activity of cobalt-based oxides, a type of 1D copper-cobalt hybrid oxide nanowires (CuCoO-NWs) is developed via a facile two-step growth-conversion process toward a bifunctional water splitting catalyst. The CuCoO-NWs exhibit excellent catalytic performances for both HER and OER in the same basic electrolyte, with optimized low onset overpotentials and high current densities. The efficient HER activity is ascribed to the formation of Cu 2 O, while the activity for OER is primarily enabled by Co-based oxides and abundant oxygen vacancies. The CuCoO-NWs allow for the assembly of a water electrolyzer with strong alkaline media, with a current density of 10 mA cm −2 at 1.61 V. Further combination with a commercial silicon photovoltaic allows the direct use of solar energy for spontaneous water splitting with excellent stability for over 72 h, suggesting the potential as a promising bifunctional electrocatalyst for efficient solar-driven water splitting.

All‐In‐One Perovskite Catalyst: Smart Controls of Architecture and Composition toward Enhanced Oxygen/Hydrogen Evolution Reactions

“…[5][6][7][8][9][10] In terms of achieving the best performances, the HER is usually carried out in an acidic environment while the OER in an alkaline condition. [5][6][7][8][9][10] In terms of achieving the best performances, the HER is usually carried out in an acidic environment while the OER in an alkaline condition.…”

“…[5][6][7][8][9][10] In terms of achieving the best performances, the HER is usually carried out in an acidic environment while the OER in an alkaline condition. [5][6][7][8][9][10][14][15][16][17][18] As a result, perovskites are being spotlighted as promising candidates due to their favorable compositional flexibility and good stability in a wide range of electrochemical window, thus enabling easy modification of their catalytic properties. In this context, a bifunctional electrocatalyst with high activities for both the OER and HER in an identical condition is desired.…”

Solar‐to‐Hydrogen Energy Conversion Based on Water Splitting

“…[87][88][89][90] To reduce the activation energies of HER and OER, numerous catalysts have been developed and loaded in various forms on the surfaces of light-absorbing materials. [87][88][89][90] To reduce the activation energies of HER and OER, numerous catalysts have been developed and loaded in various forms on the surfaces of light-absorbing materials.…”

Modular Design of Noble‐Metal‐Free Mixed Metal Oxide Electrocatalysts for Complete Water Splitting

“…[13] ForO ER, [5] the leading electrocatalysts are homoand heterometallic transition metal oxides, [14,15] hydroxides, [16,17] phosphates, [18] and nitrides. [22] In contrast, less research has been devoted to bifunctional metal oxides for complete watersplitting,a lthough ground-breaking studies have explored copper cobalt oxide nanowires [23] and nickel cobalt oxide nanoflakes [24] on metal electrodes as well as iron nickel oxide nanoparticles on carbon nanofibers [25] for OER/HER electrocatalysis.Here we report amodular design approach where several metal oxide components are rationally targeted to introduce electrical conductivity,O ER/HER catalytic activity and structural stability into ac omposite electrocatalyst. In addition, HER and OER electrocatalysis share common challenges including the need for high electrical conductivity,t he stable catalyst-electrode anchoring and others,s ot hat ac onvergent OER/HER catalyst design could overcome major current obstacles in electrocatalysis.T od ate,o nly few materials have shown this broad range of properties and most pioneering studies have used metal phosphides such as nickel phosphides, [20] iron nickel phosphides, [6] and nickel cobalt phosphides [21] or nickel selenide nanosheets.…”

“…[19] In contrast, the design of bifunctional catalysts capable of OER and HER electrocatalysis is still in its infancy and faces major challenges,asnew catalysts are needed, which feature the redoxchemistries,s tabilities and catalytic capabilities for reductive and oxidative proton-coupled electron transfers.H owever, the design of bifunctional OER/HER electrocatalysts offers vast advantages as it would simplify catalyst design and fabrication, prevent cross-contamination, materials incompatibilities and possible catalyst poisoning and is therefore of enormous technological interest. [22] In contrast, less research has been devoted to bifunctional metal oxides for complete watersplitting,a lthough ground-breaking studies have explored copper cobalt oxide nanowires [23] and nickel cobalt oxide nanoflakes [24] on metal electrodes as well as iron nickel oxide nanoparticles on carbon nanofibers [25] for OER/HER electrocatalysis. [22] In contrast, less research has been devoted to bifunctional metal oxides for complete watersplitting,a lthough ground-breaking studies have explored copper cobalt oxide nanowires [23] and nickel cobalt oxide nanoflakes [24] on metal electrodes as well as iron nickel oxide nanoparticles on carbon nanofibers [25] for OER/HER electrocatalysis.…”