Engineered built-in electric fields in Cu⁰/CuO_x nanozyme-decorated silicon nanodisks for the degradation of phenols and dyes

Laccase has demonstrated potential for the treatment of hazardous pollutants; however, its widespread application is hindered by stability issues. In contrast, nanozymes, with their remarkable stability, present a promising alternative. In this study, we developed silicon-anchored Cu⁰/CuO_x nanozymes exhibiting laccase-like activity for the oxidation removal of phenols and dyes. The valence states of the copper species, which emerged through spontaneous oxidation, played a crucial role in creating a heterogeneous interface, exerting a significant impact on the catalytic efficacy of the copper nanozymes. By employing density functional theory (DFT) calculations, we revealed that the existence of a local built-in electric field (BIEF) among the heterogeneous components facilitated the cyclic consumption of Cu⁰ and the migration of lattice oxygen. This dynamic interplay modulated the levels of Cu⁺ and oxygen vacancies (OVs), thereby allowing for sustained catalytic performance within a defined period. Our findings underscore the importance of valence engineering in the rational design of nanozymes and highlight their potential as efficient catalysts for advancing environmental sustainability.