Enhancing multifunctional photocatalysis with acetate‐assisted cesium doping and unlocking the potential of Z‐scheme solar water splitting

Abstract Graphitic carbon nitride (g‐C₃N₄) has been extensively doped with alkali metals to enlarge photocatalytic output, in which cesium (Cs) doping is predicted to be the most efficient. Nevertheless, the sluggish diffusion and doping kinetics of precursors with high melting points, along with imprecise regulation, have raised the debate on whether Cs doping could make sense. For this matter, we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation. The optimized Cs‐doped g‐C₃N₄ (CCN) shows a 41.6‐fold increase in visible‐light‐driven hydrogen evolution reaction (HER) compared to pure g‐C₃N₄ and impressive degradation capability, especially with 77% refractory tetracycline and almost 100% rhodamine B degraded within an hour. The penetration of Cs⁺ is demonstrated to be a mode of interlayer doping, and Cs–N bonds (especially with sp² pyridine N in C═N–C), along with robust chemical interaction and electron exchange, are fabricated. This atomic configuration triggers the broadened spectral response, the improved charge migration, and the activated photocatalytic capacity. Furthermore, we evaluate the CCN/cadmium sulfide hybrid as a Z‐scheme configuration, promoting the visible HER yield to 9.02 mmol g⁻¹ h⁻¹, which is the highest ever reported among all CCN systems. This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.