Carbene-Mediated Photoconversion of Cellulose Diacetate

Amid rising global demand for renewable energy and effective plastic waste management, adopting green methods to utilize plastic waste for chemicals is a win-win strategy. Constituting the largest amount of single-use plastic litter worldwide, cellulose diacetate (CDA) based waste cigarette filters urgently require sustainable valorization pathways. However, CDA photoconversion remains highly challenging due to substantial energy barriers for selective bond cleavage, inadequate radical generation capability, and inefficient charge-carrier separation. Herein we propose a strategy to efficiently obtain C₂H₄ through carbene-mediated CDA photoconversion by using a sulfur vacancy-regulated copper-gallium-zinc-sulfide (V_S-CGZS) catalyst. V_S-CGZS enhances the thermal effect of light and lowers the energy barrier for acetyl group (*CH₃CO) desorption from CDA. V_S reduces the adsorption energy of *CH₃CO on V_S-CGZS and facilitated :CH₂ formation. Consumption of photogenerated holes via *CH₃CO desorption and V_S-enhanced carrier separation synergistically elevate the photogenerated electrons concentration for :CH₂ coupling, thereby selectively triggering and boosting C₂H₄ yield. Therefore, we achieve a record-breaking 14.43 mmol·g_cat^-1 C₂H₄ for CDA photoconversion within 4 h, over 6 times exceeding previous reports on photoconverting plastic into C₂H₄. This work establishes a strategy for efficient ethylene production from photoconversion of cellulose diacetate and carves out a paradigm in solar-driven plastic valorization.