Unlocking the potential of Bi₂S₃ for photocatalysis: a roadmap for next-generation solar catalysts

Photocatalysis enables the direct conversion of solar energy into chemical fuels, presenting a compelling strategy to mitigate the global energy crisis and environmental pollution. However, traditional photocatalysts are severely hampered by inefficient visible-light harvesting and undesirably rapid recombination of photogenerated carriers, which bottlenecks their large-scale practical deployment. Thus, developing efficient, stable, and broadband-responsive photocatalytic materials remains a paramount research imperative. Bismuth sulfide (Bi₂S₃), a prototypical narrow-bandgap semiconductor, has recently garnered immense interest. Its judiciously positioned band edges and strong visible-light absorption confer distinct advantages for solar-driven photoredox reactions. Despite significant advances, the field still lacks a comprehensive and timely review consolidating Bi₂S₃-based artificial photosystems. This review systematically summarizes the latest progress in Bi₂S₃-based photocatalysts, with a particular focus on morphology control, heterojunction construction, elemental doping, and defect engineering. We elucidate how these strategies precisely manipulate the electronic structure, facilitate charge separation, broaden light absorption, and enhance material stability. Furthermore, we outline critical future perspectives: (i) designing novel multicomponent architectures, (ii) unraveling the kinetic mechanisms of interfacial carrier transfer, and (iii) validating scalable performance under realistic environmental conditions. This review provides a holistic roadmap for Bi₂S₃-mediated photoredox catalysis, serving as a vital resource for researchers advancing solar energy conversion technologies.