Mechanistic insight into sp-hybridized carbon-induced dual electronic 'push effect' in Pt/graphdiyne/graphene for boosting oxidase-like activity.

Efficient oxidase-mediated oxidation is pivotal for environmental remediation and energy conversion application, yet natural enzymes require artificial alternatives due to inherent instability. Cofactors are essential in natural oxidase catalysis, interacting with the active centre to induce an electronic 'push effect' that propels the catalytic process. While efforts to mimic cofactors in nanozyme often involve sophisticated designs and complex synthesis. This study presents a scalable material engineering approach to mimic cofactor functionality using platinum nanoparticles (Pt NPs) supported on an ultrathin graphdiyne/graphene (GDY/G) composite (Pt/GDY/G), in which the sp-hybridized carbon (sp-C) in GDY induces a dual electronic 'push effect'. The unique sp-C structure in GDY imparts semiconductor characteristics and a low work function, this induces an interfacial electrostatic potential between GDY and Pt, which enables unidirectional electron transfer from GDY to Pt, thereby enhancing the electron density at Pt sites. Moreover, the sp-C sites in GDY act as oxygen (O) adsorption centres, forming a spCOO-Pt bridge that facilitates electron transfer from GDY to O. This sp-C induced dual electronic 'push effect' significantly reduces the energy barrier for OO bond cleavage, resulting in a 3.4-fold enhancement of the oxidase-like (OXD-like) activity of Pt/GDY/G compared to Pt NPs alone. This work provides mechanistic insights into the design of OXD-like nanozymes, offering a promising strategy to boost O activation and OO bond cleavage. The superior catalytic performance of Pt/GDY/G highlights its potential for dye and microplastics degradation, contributing to sustainable environmental remediation.