Interfacial microenvironment and catalyst modulation for efficient hydrogen peroxide synthesis via mimicking oxidase catalysis

Abstract

The two-electron oxygen reduction reaction driven by nanocatalysts that mimic formic acid oxidase catalysis is a promising approach for H₂O₂ synthesis under mild conditions without using light or electricity. However, in conventional reaction systems, the activity of the nanocatalysts and the production rate of H₂O₂ are generally restricted by the slow diffusion rate and low solubility of the reactant O₂ in water. Thus, it is of crucial importance to develop an efficient catalytic system that can address the O₂ deficiency issue, help to explore the intrinsic activity of catalysts and maximize their catalytic performance. In this study, combining interface microenvironment and material modulation, we fabricated an air–liquid–solid triphase reaction system that allows the rapid delivery of O₂ via the air phase to the reaction zone, and synthesized a series of Au_xPt_100−x–TiO₂ nanocatalysts for efficient H₂O₂ generation. We constructed a theoretical model to simulate O₂ concentration in different reaction conditions. Combined with experiments, it reveals that the interfacial O₂ concentration of the triphase system is much higher than that of the conventional solid–liquid diphase system. The triphase system maximizes the performance difference between catalysts, and enables us to discover that the Au₉₃Pt₇–TiO₂ catalyst exhibits the highest H₂O₂ production rate (4.43 mmol g⁻¹ h⁻¹) under mild conditions. The synergistic effect between the interface architecture and the catalyst leads to a 5-fold enhancement in H₂O₂ productivity.