Piezocatalytic oxidation of lignin-derived phenol to p-benzoquinone: a sustainable route for green polymerization inhibitors

Abstract

Conventional processes for the conversion of lignin-derived phenol to p-benzoquinone (p-BQ) are associated with environmental concerns and efficiency issues, which necessitates the development of greener and more selective alternatives. This study reports a sulfur vacancy-engineered 2H-MoS₂ piezoelectric catalyst that enables efficient phenol conversion under mild aqueous/air conditions. The optimized catalyst exhibits outstanding performance, achieving a 92.57% phenol conversion and a 66.56% p-BQ yield within 6 hours. Integrated experimental and theoretical studies elucidate that sulfur vacancies play a pivotal dual role. Beyond enhancing the material's piezoelectric response and optimizing charge carrier dynamics, they function critically within the reaction mechanism by (1) acting as active sites that promote the adsorption of phenol and the subsequent desorption of p-BQ, and (2) selectively modulating the proportion of hydroxyl radicals (˙OH) among the various reactive species. This work clarifies the central role of defect engineering in modulating active species and product selectivity, offering a new strategy for the green valorization of lignin derivatives.