Spatially separated redox active sites over Re-Ni@Ni(OH)2 core-shell structure for enhancing furfural oxidation coupled with hydrogen evolution

The design of bifunctional catalysts with spatially separated active sites holds significance importance in achieving simultaneous electrooxidation and hydrogen evolution reaction (HER). Herein, a core-shell Re-Ni@Ni(OH) 2 /CC heterostructure is demonstrated for the electrocatalytic furfural oxidation reaction (FOR) coupled with HER. Experimental results and theoretical analyses reveal that Re not only modulates the heterointerface between Re-Ni core and Ni(OH) 2 shell, facilitating furfural (FF) adsorption at Ni(OH) 2 sites, but also regulates electronic structure of Ni. This leads to a negative shift in the d-band center from Fermi level, effectively weakening hydrogen adsorption at Ni sites in Re-Ni@Ni(OH) 2 heterostructure, thereby improving the HER process. As a result, the synthesized Re-Ni@Ni(OH) 2 /CC exhibits a low cell voltage of 1.40 V @10 mA cm −2 for the FOR||HER. This study highlights the importance of modulating metal’s electronic structure and identifying active sites, which has great potential for improving bifunctional electrocatalytic reactions.