Sustainable HO production via solution plasma catalysis.

Clean production of hydrogen peroxide (HO) with water, oxygen, and renewable energy is considered an important green synthesis route, offering a valuable substitute for the traditional anthraquinone method. Currently, renewable energy-driven production of HO mostly relies on soluble additives, such as electrolytes and sacrificial agents, inevitably compromising the purity and sustainability of HO. Herein, we develop a solution plasma catalysis technique that eliminates the need for soluble additives, enabling eco-friendly production of concentrated HO directly from water and O. Screening over 40 catalysts demonstrates the superior catalytic performance of carbon nitride interacting with discharge plasma in water. High-throughput density functional theory calculations for 68 models, along with machine learning using 29 descriptors, identify cyano carbon nitride (CCN) as the most efficient catalyst. Solution plasma catalysis with the CCN achieves concentrated HO of 20 mmol L, two orders of magnitude higher than photocatalysis by the same catalyst. Plasma diagnostics, isotope labeling, and COMSOL simulations collectively validate that the interplay of solution plasma and the CCN accounts for the significantly increased production of singlet oxygen and HO thereafter. Our findings offer an efficient and sustainable pathway for HO production, promising wide-ranging applications across the chemical industry, public health, and environmental remediation.