Rational co-engineering of π-exciton and oxygen vacancy via a mild halide-exchange strategy: a sustainable blueprint for highly efficient S-scheme photocatalysts

Abstract

Developing mild, energy-efficient, and scalable synthetic strategies for advanced functional materials is essential for sustainable chemistry. However, the efficiency of photocatalysis, a promising solar-driven solution, is often severely limited by the severe recombination of charge carriers. Herein, we report a scalable and mild in situ anion-exchange process—a core green chemistry approach—to precisely engineer the nano-interface of a g-C₃N₄/Bi-based heterojunction. This sustainable synthesis strategy co-regulates π-excitons and oxygen vacancies (V_O), establishing a powerful vacancy-exciton synergistic effect. As confirmed by in situ spectroscopy and DFT calculations, this synergy engineers a rapid hole-transfer channel while creating robust electron traps, culminating in a remarkable 72% enhancement in interfacial charge separation efficiency. As a result, the engineered photocatalytic system demonstrates exceptional performance and stability, achieving rapid degradation of diverse antibiotics and complete inactivation of pathogenic bacteria using visible light as a sustainable energy source. This study offers a new paradigm for the rational design of robust catalysts based on green chemistry principles, demonstrating the potential of mild synthesis to achieve precise atomic-level control for practical, high-performance systems.