First‐Principles Study of Defective MoSe ₂ /g‐C ₃ N ₄ Heterojunctions for Enhanced Photocatalytic

With first‐principles calculations based on density functional theory, the impacts of carbon and nitrogen defect sites on the geometric structure, electronic properties, and photocatalytic behavior of MoSe ₂ /g‐C ₃ N ₄ heterojunctions were thoroughly investigated. Defective g‐C ₃ N ₄ can be confirmed to establish stable parallel contact‐type heterostructures with MoSe ₂ through binding energy and lattice mismatch analyses. According to the analyses of work functions, band structures, density of states, and optical absorption properties, carbon and nitrogen vacancies significantly facilitate the separation of photoinduced charges and improve the visible‐light absorption capability of materials due to the vacancy‐induced midgap states. The single N vacancy exhibits the most prominent improvement in visible‐light photocatalytic performance. The present work provides dependable theoretical guidance for the development of efficient defect‐engineered composite photocatalytic materials.