Strengthening the Stability of the Reconstructed NiOOH Phase for 5-Hydroxymethylfurfural Oxidation

Electrochemical oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) is a promising approach to produce high-value chemicals such as 2,5-furandicarboxylic acid (FDCA). However, the undesirable stability of catalysts commonly limits its potential application value. In this work, NiOOH derived from Ni(OH)₂ was determined as the main catalytic site for HMF oxidation, but the collapse of Ni(OH)₂ caused severe instability during the electrocatalytic process because of the crystal structure mismatch between NiOOH and Ni(OH)₂. The implantation of Ce in Ni(OH)₂ (Ce-Ni(OH)₂) was successfully realized to address the stability issue of bare Ni(OH)₂, since the larger ion radius of Ce could increase the Ni-O bond length and d-spacing. As a result, the activity of 14%Ce-Ni(OH)₂ has not obviously decayed after the 50 cyclic voltammetry (CV)-cycle test. HMF conversion is close to 100%, and the Faraday efficiency (FE) reaches 86.6% at the potential of 0.45 V vs Ag/AgCl. This study provides a new strategy to design stable catalysts for the conversion of biomass derivatives.