Amino-Tethered Ni3S2/MoS2 Heterojunction for Coupling Electrochemical 5-Hydroxymethylfurfural Oxidation with 4-Nitrophenol Hydrogenation

Paired electrocatalytic systems have emerged as a promising approach for the synthesis of high-value-added fine chemicals from renewable resources like biomass, however, a high-performing bifunctional catalyst is urgent to reduce the overall cell voltage and enhance the current efficiency. Herein, amino-tethered Ni3S2/MoS2 heterojunction (NiMoSx-NH2) was constructed as the bifunctional catalyst simultaneously for the anodic 5-Hydroxymethylfurfural oxidation into furan dicarboxylic acid and cathodic 4-nitrophenol hydrogenation into P-aminophenol, providing the high conversion/yield/Faradic efficiency above 98% on both electrodes. Amino-tethered Ni3S2/MoS2 heterojunction, on the one hand, accelerated the electron transfer, and on the other hand, promoted the catalysts’ proton-coupled electron transfer process to generate NiIII-O(OH)ad at the anode and H* desorption at the cathode. A highly efficient paired electrolyzer with NiMoSx-NH2 as a bifunctional catalyst was assembled, showing an extremely low cell voltage of 0.89 V at 10 mA cm-2 and ~200% current efficiency at 1.75 V for the overall reaction.