Effective electrocatalytic xylose oxidation coupling hydrogen production on hierarchical microcolumn NiMoO4 array
Bin Liu, Huiming Wen, Bo Da, Xiaoying Liang, Ke Li, Zhenhao Xu, Xiaodie Zhang, Yutong Zhang, Yuchen Wang, Hao Li, Kai Yan
Abstract
The simultaneous realization of biomass conversion and clean energy hydrogen (H 2 ) production remains a desirable but challenging objective. Herein, we present a strategy that simultaneously enables anodic electrocatalytic xylose oxidation (EXO) coupling with the cathodic hydrogen evolution reaction (HER). In the EXO process, the hierarchical microcolumn NiMoO 4 array exhibits excellent performance, achieving 200 and 231 mV reduction of overpotential compared to the oxygen evolution reaction at 10 and 50 mA cm −2 , respectively, and an overpotential of 130 mV lower than that of Ni foam at 50 mA cm −2 . The mechanism studies reveal that the OH* are effective active species to facilitate the EXO process. For HER, the P-doped NiMoO 4 (P-NiMoO 4 ) electrode exhibits remarkable HER performance, achieving 64 and 197 mV overpotential at 10 and 50 mA∙cm −2 , respectively. These are far superior to most of the previous studies. The P-NiMoO 4 electrode maintains high durability over 110 h across various current densities. The incorporation of P modifies the electronic environment of NiMoO 4 , enhancing the adsorption of H*, and thereby improving HER activity. In the assembled system, the paired reactions have low voltages of 0.81 and 1.53 V at 10 and 50 mA cm −2 , respectively, a high Faradaic efficiency of 80%, and decent durability over 100 h. This work offers a guideline for the sustainable synthesis of value-added chemicals and clean H 2 via paired electrocatalytic biomass refining.