Performance Promotion of Multipurpose Catalysts Using Increased Oxygen Vacancy Amounts by Charge-Mismatched Doping.

Modulating the oxygen vacancy ( V 0 ) in nanostructures has opened a new avenue for efficient catalyst design, facilitating biomass oxidation reactions and electrocatalytic properties. In this study, we have investigated the properties of NiO-based catalysts with varying degrees of V 0 achieved through ion doping of the catalyst with cations of different oxidation states (TM 3+ ) or the same valence state (TM 2+ ) as Ni 2+ in the NiO matrix. By introducing charge-mismatched dopants, we enhanced the concentration of V 0 in the NiO catalyst, resulting in remarkable selectivity (∼50%) for the conversion of 2,5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), as well as a lower overpotential in the oxygen evolution reaction (OER). We believe that charge-mismatched doping offers a novel avenue for optimizing defect engineering in oxide-based catalysts, which can enable more efficient biomass conversion and water splitting. These findings have made a significant contribution to the field of multipurpose catalysis and hold the potential to inspire new catalyst designs that would usher in a more sustainable future.