ABSTRACT Heterogeneous photocatalysis has progressively evolved to address solar‐to‐chemical energy conversion bottlenecks. Although earlier generations established foundational principles, they faced limitations in atomic efficiency and charge transfer. This review critically analyzes fourth generation photocatalysts, a paradigm defined by atomic precision and dynamic interface engineering on TiO 2 platforms. Distinct from classical models, this generation leverages electronic/covalent metal–support interactions, where single‐atom catalysts chemically integrate into the lattice via direct orbital bonding (e.g., Ti‐O‐M) to bypass recombination traps. We examine key charge separation breakthroughs, including self‐healing redox cycles in Cu single atoms (56% quantum efficiency), exciton‐mediated transfer in Mo‐doped systems, and synergistic dual‐junction architectures. Furthermore, the pivotal role of defect engineering (Ti 3 + , oxygen vacancies) in stabilizing atomic sites and tuning selectivity is highlighted. This review offers a unified framework for designing next‐generation photocatalysts that overcome intrinsic bulk semiconductor limitations through atomic‐level innovations.
Jang et al. (Sun,) studied this question.