High-entropy carbide as cocatalyst for TiO2 in photocatalytic CO2 reduction

Abstract

One of the major challenges in modern materials science is the development of new efficient functional materials for sustainable energy applications. We propose and investigate a novel cocatalyst for photocatalytic applications - high-entropy carbide HfTaZrNbTiC5 (HEC) synthesized by vacuumless electric arc plasma technique. A series of composite photocatalysts HEC/TiO2 with different mass contents of HEC are tested in CO2 reduction reaction under visible light irradiation and all samples showed significant improvement in CH4 production compared to unmodified TiO2. The highest rate achieved at 10 wt % HEC/TiO2 is equal to 3.5 μmol h−1 gcat−1, which is 7 times higher than that of TiO2. Density functional theory calculations of the proposed methanation reaction agreed with the provided experiments explaining the limiting reaction rate of methanation and confirming the higher efficiency of the composite catalysts compared to TiO2. The findings highlight HECs as a versatile platform for sustainable CO2 valorization and solar fuel generation.