2D High-Entropy Phosphorus Chalcogenides for Efficient Solar-Driven CO₂ Reduction to Ethylene.

Abstract

Solar-driven CO₂ reduction to value-added ethylene (C₂H₄) is considered as a promising and mild approach for storing solar energy into chemical bonds in fuels and chemicals, yet the thermodynamic obstacles related to CO₂ activation and C─C coupling significantly limit the practical application of this approach. Developing high-entropy materials (HEMs), featuring multi-principal elements and high configurational entropy, has emerged as a topic of considerable interest for addressing the aforesaid challenge. Herein, an emerging 2D high-entropy phosphorus chalcogenide (HEPC), Cu(CrVInFeMnNi)P₂S₆, is rationally developed as a multifunctional photocatalyst via integrating multiple cations into the frame of CuCrP₂S₆. The Cu site in the HEPC serves as the dominant active center for activating CO₂ and achieving C─C coupling for solar-driven CO₂ to C₂H₄. Besides, the multi-metal matrix of Cr, V, In, Fe, Mn, and Ni sites leads to a multi-site integrated electron-donation effect in HEPC, where these different metal sites form a d-band gradient arrangement in HEPC as well as act as the auxiliary electron-donating centers for increasing the charge density of the Cu site and significantly boosting C─C coupling. As a result, Cu(CrVInFeMnNi)P₂S₆ achieves an ultrahigh apparent quantum yield (AQY) of 7.4% at 475 nm for solar-driven CO₂ to C₂H₄ (a superior C₂H₄ selectivity of 71%) under the sacrificial-agent-free condition, outperforming the vast majority of state-of-the-art photocatalysts. This work pioneers the application of high-entropy phosphorus chalcogenides in catalysis and provides a new idea for the development of efficient multifunctional materials.