Tuning the adsorption behaviors of non-noble electrocatalysts to boost valorization of 5-hydroxymethylfurfural

Abstract

Nickel-based non-noble materials have been widely used as catalysts for a variety of electrosynthesis reactions due to their low cost and tunable surface properties. However, few of them perform well for the 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) due to their weak adsorption capacity for low-concentration reactants. In this work, Ox-NiCuO_z derived from mixed metal oxide (NiCuO_z) via anodic reconstruction is employed for the HMFOR, which remarkably outperforms Ox-NiCu(OH)_z derived from NiCu-hydroxide (NiCu(OH)_z). A series of ex/in situ investigations and theoretical calculations reveal that the adsorptions of HMF and intermediates are enhanced on the low-coordinated surface sites of Ox-NiCuO_z, which facilitates the dynamic Ni^II/Ni^III transformation and hence boosts the HMFOR. In addition, Red-NiCuO_z derived via cathodic reconstruction is employed for the HMF reduction reaction (HMFRR). As a result, a paired HMFOR/HMFRR electrolysis is conducted using Ox-NiCuO_z//Red-NiCuO_z as the electrode pair, simultaneously yielding value-added products of 2,5-furandicarboxylic acid (FDCA) and 2,5-bishydroxymethylfuran (BHMF) with a combined faradaic efficiency (FE) of nearly 150% at 2 V. This study provides not only a guideline for non-noble catalyst design towards organic electrosynthesis, but also a rational scenario of paired electrolysis for highly efficient biomass utilization.