Materials and microenvironment engineering for high-efficiency nitrate photoreduction: Status and perspectives

Photocatalytic nitrate reduction is an environmentally beneficial technique that uses sun energy to transform nitrate into safe or valuable goods. It has vast potential for environmental cleaning and energy conversion. Nevertheless, its practical applicability is limited by its low reaction efficiency and the presence of various unexpected reaction products. This review aims to enhance the reaction activity of photocatalytic nitrate reduction. To achieve this, we first elucidate the underlying reaction principles and pathways. Following this, the techniques for modifying catalysts, including morphological control, element doping, heterostructure creation, defect introduction, and noble metal loading, are discussed. These approaches are then analyzed in terms of their ability to enhance photocatalytic activity and product selectivity. In addition, the effects of the types of hole scavenger, the initial concentration of nitrate ions and other reaction microenvironments on the reduction efficiency and product selectivity were systematically investigated. The paper finishes by summarizing the results, recommending options for additional exploration, and providing direction for the development of effective nitrate reduction systems and photocatalysts. This study aims to inspire new ideas for the enhancement of catalyst design and reaction efficiency in photocatalytic nitrate reduction by offering insightful guidance for forthcoming advances.