Interfacial Electronic Engineering of Co-doped Ni(OH)2 Nanoarrays for Efficient Electrooxidation of Xylose to Formate

Abstract

The electrochemical oxidation of biomass-derived xylose (XOR) to formate offers a sustainable route for chemical production and renewable energy integration. However, conventional Ni-based catalysts suffer from a high overpotential for generating the active Ni3⁺ species and competing side reactions, which limit their achievable current density and selectivity. Herein, we design Co-doped Ni(OH)2 nanoarrays on carbon felt to overcome these limitations. The catalyst exhibits an exceptionally low potential of 1.34 V vs. RHE at 100 mA cm⁻2 for XOR, which is 242 mV lower than that for the oxygen evolution reaction. while delivering a formate Faradaic efficiency >92% and maintaining stable performance over 132 hours at 250 mA cm-2. Mechanistic studies reveal that Co doping induces electron transfer from Ni to Co via bridging oxygen atoms, forming Ni-O-Co interfacial units that serve as efficient electron channels to accelerate charge transfer and reduce the energy barrier for Ni3⁺ formation. Coupled with a superhydrophilic and superaerophobic nanoarray architecture that ensures superior mass transport, the catalyst delivers stable, high-rate performance. This work elucidates the role of interfacial electronic engineering and nanostructure design in modulating reaction energetics, providing an effective strategy for high-performance biomass electrooxidation.