Boosting HMF oxidation performance via decorating ultrathin nickel hydroxide nanosheets with amorphous copper hydroxide islands

Abstract

Effective valorisation of biomass into value-added chemicals represents a promising strategy to reduce the reliance on fossil fuel energy, and 5-hydroxymethylfurfural (HMF) has been identified as a critical and versatile platform chemical among many biomass-derived intermediates. Electro-catalytic HMF oxidation into 2,5-furandicarboxylic acid (FDCA), a key monomer for biobased polymers, in an ecofriendly and cost-effective manner has recently emerged as a promising solution compared with conventional thermo-catalytic strategy that relies on high pressure O₂ and elevated temperatures. Herein, ultrathin Ni(OH)₂ nanosheets decorated with amorphous Cu(OH)₂ islands are identified to be a highly efficient catalyst for the selective electrooxidation of HMF. Long-term chronoamperometry demonstrates a high faradaic efficiency of 91.2% towards FDCA production, and the HMF oxidation is determined to proceed follow a DFF pathway. Nickel species are proposed to be the active sites for HMF oxidation, while amorphous copper hydroxide functions to strengthen the affinity for reaction intermediates and modulate the electronic structure of Ni, leading to an earlier onset for HMF oxidation. The catalyst design strategy proposed in this work has shown great potential in improving HMF electrooxidation efficiency, which is essential for the widespread application of HMF electrooxidation.