Synergistic Doping and Microenvironment Engineering Enable Efficient Electrocatalytic Oxidation of 5-Hydroxymethylfurfural

Abstract

The electrocatalytic stabilization of 5-hydroxymethylfurfural oxidation reaction (HMFOR) alongside hydrogen production offers an effective and cost-efficient approach to attaining a zero-carbon economy. Nickel-based electrocatalysts are viable options owing to their intrinsic redox properties; yet, HMFOR entails many hydroxide ions (OH-) and multi-electron synergistic catalytic mechanisms in alkaline electrolytes. The limited OH- capture capacity of nickel-based catalysts results in diminished energy conversion efficiency. Furthermore, the inadequate intrinsic catalytic activity of nickel and its propensity to reorganize into a singular hydroxide at elevated potentials results in aggregation. To tackle these issues, we developed a new catalyst (Co-NiO/Cr2O3) employing an approach that integrates heteroatom doping and microenvironment engineering. Experimental data indicate that this catalyst attains a Faradaic efficiency of 99.2% and a selectivity for 2,5-furan dicarboxylic acid (FDCA) of 99.17%. The doping of cobalt precisely modulates the coordination environment of nickel, whereas Cr2O3 serves as a quintessential Lewis acid, with its surface Cr3+ sites exhibiting a robust ability to receive electron pairs, thereby accumulating hydroxide ions from the solution and establishing a localized basic environment at the active sites. This work presents an innovative and effective HMFOR catalyst while also proposing a new approach for the design and development of catalysts for value-added biomass conversion.