Recent advances and challenges of double-atom catalysts in diverse environmental applications: A state-of-the-art review

Abstract

Single-atom catalysts (SACs) have drawn great attention in environmental applications because of their nearly 100 % atomic utilization efficiency and tunable electronic structure. However, the scaling relationship between solo active site and multiple reactants/intermediates severely hampers further development of SACs. Recently, double-atom catalysts (DACs) with different active sites and synergistic interactions show great promise in overcoming the scaling relationship limit of SACs, offering new opportunities for environmental applications. Herein, the recent advances of DACs for diverse environmental applications are reviewed. Firstly, the classification, superiority and activity origins of DACs are systematically summarized. In particular, the superiorities of DACs mainly involve adsorption effect, electronic effect, bifunctional effect, and electronic metal-support interaction. The synthetic methods and characterization techniques are also described. Subsequently, the applications of DACs in environment-related field are carefully discussed, including wastewater treatment, air purification, plastic conversion, disinfection, sensor, desulfurization of fuel and CO₂ reduction. Emphasis is concentrated on the elucidation of in-depth reaction mechanisms and corresponding structure-reactivity relationships. Finally, several major challenges and future directions in these fields are also proposed. This article is beneficial to providing new inspiration for the rational design and development of efficient DACs toward environmental applications.