Dual‐Site Interfacial O 2 Adsorption in a p‐n vdW Heterojunction Boosts Photocatalytic H 2 O 2 Production for Antibacterial Applications

Abstract Precise engineering of dual‐site diatomic O 2 adsorption plays a pivotal role in facilitating the one‐step two‐electron oxygen reduction reaction (2e − ORR) for efficient photocatalytic H 2 O 2 production. However, achieving this remains challenging due to the stringent geometric and electronic requirements for O 2 adsorption sites. Herein, a metal‐free vdW heterojunction is presented by electrostatically coupling p‐type polypyrrole‐derived carbon (PPy‐800) with n‐type g‐C 3 N 4 nanosheets (CN m ). The resulting heterojunction enables spatially resolved nitrogen‐based active sites, with edge N atoms from CN m and azido species from PPy‐800, cooperatively anchoring O 2 molecules in a dual‐site configuration. Density functional theory (DFT) calculations reveal that this arrangement significantly reduces the adsorption energy of O 2 and promotes directional charge separation and transfer through an internal electric field at the p‐n junction interface. The optimized heterojunction, designated CN p1m10 (with a mass ratio of PPy‐800: CN m = 1: 10), achieves a H 2 O 2 production rate of 10415.27 µmol g −1 h −1 under visible light in the presence of 10% isopropanol. Remarkably, even in pure water, CN p1m10 achieves a solar‐to‐chemical conversion (SCC) efficiency of 1.31%, alongside potential antibacterial activity. This work highlights the importance of rational interfacial design for dual‐site O 2 adsorption in advancing metal‐free photocatalysts for sustainable H 2 O 2 production.