Photocatalytic synthesis of hydrogen peroxide: recent advances, challenges, and future perspectives.

Hydrogen peroxide (HO), an eco-friendly oxidant and multifunctional chemical feedstock, is widely used in medical disinfection, paper bleaching, green chemistry, and environmental management. However, the traditional industrial anthraquinone process, which involves high energy consumption and causes severe environmental pollution, is becoming increasingly unsuitable for the rising demand for sustainable and eco-friendly production methods. In response, several innovative production strategies have been developed. Among these, photocatalytic HO production is a sustainable and cost-effective process that uses water (HO), gaseous oxygen (O), and light as primary inputs. However, the limited light absorption, rapid particle interactions, and insufficient activation of sites in traditional photocatalysts hinder high yields in photocatalytic HO production. Achieving sustainable HO production from HO and O photocatalysis still remains a significant challenge. This review explores the core mechanisms of photocatalytic HO production, emphasizing the oxygen reduction and water oxidation pathways. It then provides an overview of recent advancements in the development of advanced photocatalytic materials designed specifically for HO generation, mainly including graphitic carbon nitride (CN), metal-organic frameworks (MOFs), and covalent organic frameworks (COFs), along with various modification strategies to improve their performance. Finally, it offers insights on addressing challenges and exploiting opportunities in photocatalytic HO production. This work aims to assess current challenges and advancements in HO photosynthesis while offering insights into developing highly efficient photocatalysts for improved photocatalytic HO production.