Ni-Cu-based phosphide heterojunction for 5-hydroxymethylfurfural electrooxidation-assisted hydrogen production at large current density

Abstract

5-hydroxymethylfurfural oxidation reaction (HMFOR) offers a promising avenue to achieve energy-saving H2 production and produce value-added chemicals. However, the lack of HMFOR electrocatalysts with large current density and high selectivity impedes the whole productivity. Herein, an Ni3P-Cu3P heterojunction grown on Cu foam (Ni3P-Cu3P/CF) was successfully constructed, achieving large current density (300mAcm-2 at 1.60V vs. RHE) and high selectivity and Faradaic efficiency (>99%) for HMFOR. The X-ray photoelectron spectroscopy and theoretical calculations reveal that the interface charge redistributes at the Ni3P-Cu3P heterointerface, resulting into the charge-deficiency Ni3P and charge-accumulation Cu3P. The charge-deficiency Ni3P induced by charge-attracting Cu3P favors to form more high-valence Ni species, which facilitates to optimize the adsorption of HMF and OH⁎ species for improving current density and decreasing potential, while the charge-accumulation Cu3P enables to broaden the potential window by suppressing competitive oxygen evolution reaction, thus elevating the conversion rate and selectivity of products. Benefiting from the excellent performance of Ni3P-Cu3P/CF for HMFOR, when constructing a HMFOR-assisted H2 production system using Ni3P-Cu3P/CF and self-prepared MoNiNx/NF as anode and cathode, the energy consumption was substantially decreased to 3.8kW•h/Nm3 relative to that of pure water splitting (4.66kW•h/Nm3). Our work is instructive for achieving low energy consumption of H2 production and synthesis of valuable chemicals by constructing heterojunction.