Construction of a hierarchically structured, NiCo–Cu-based trifunctional electrocatalyst for efficient overall water splitting and 5-hydroxymethylfurfural oxidation. Issue 16 (12th July 2021)

• Record Type: Journal Article
• Authors: Zheng, Ruijuan; Zhao, Chenhao; Xiong, Jinhua; Teng, Xue; Chen, Wuhua; Hu, Zhibiao; Chen, Zuofeng
• Is Part Of: Sustainable energy & fuels. Volume 5:Issue 16(2021)
• Page Start: 4023
• Page End: 4031
• Publication Date: 2021-07-12
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d1se00697e
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : A hierarchically structured, NiCo–Cu-based trifunctional electrocatalyst was fabricated for efficient overall water splitting and 5-hydroxymethylfurfural oxidation. Abstract : In this study, Cu nanowire arrays grown on a three-dimensional Cu foam substrate are modified by nickel–cobalt layered double hydroxide nanosheets (NiCoNSs /CuNWs ), which can be used as a self-supporting trifunctional electrocatalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and 5-hydroxymethylfurfural (HMF) oxidation. This hybrid material as an electrocatalyst possesses remarkable advantages including low cost, freestanding nature, high conductivity and a unique hierarchical structure with a potential bimetallic synergistic effect. The optimized NiCoNSs /CuNWs electrode shows excellent HER and OER performances in alkaline solution, making it a remarkable bifunctional electrode for efficient overall water splitting. When assembling a two-electrode electrolytic cell with NiCoNSs /CuNWs as both the anode and cathode, it requires an applied cell voltage of only 1.69 V to deliver a current density of 10 mA cm −2 in water electrolysis. Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) is also carried out in 1.0 M KOH. HMF oxidation occurs upon the formation of Ni 3+ species, leading to earlier catalytic onset (around 300 mV ahead) in comparison with the OER trigged by the higher-oxidation-state Ni 4+ species. When HMF oxidation and H2 evolution are integrated into a two-electrode electrolyzer with the NiCoNSs /CuNWs catalyst couple, the voltage required to achieve a current density of 10 mA cm −2 is 1.44 V, approximately 250 mV lower than that of overall water splitting. The present work provides useful guidance for designing and developing efficient multifunctional electrocatalysts for energy-saving hydrogen production coupled with oxidative biomass upgrading.