Polar components in biochar boost oxygen vacancies and electron transfer for enhancing the degradation of tetracycline.

Abstract

Traditional modification methods focus on promoting the formation of oxygen vacancy (OV) primarily through external condition regulation while overlooking the influence of the polar components of substrate materials. Herein, we have prepared biochar-supported cerium oxide materials (CeO₂/PBCs) with different contents of polar components on biocarbon and explored the role of polar components in modulating the structural and electronic properties of CeO₂/PBCs, which are effectively applied to the degradation of tetracycline (TC). Characterization data and density-functional theory (DFT) calculations show that polar components, including carbon defects and oxygen-containing functional groups (OCGs), can weaken Ce-O through their electron enrichment effect, which can promote the oxygen separated from CeO₂ to the formation of OV. Furthermore, these polar components increase the electron transit efficiency of carbon, which improves the electrochemical performance of CeO₂/PBC and favors the promotion of OV generation. The optimized CeO₂/PBC-400 showed the highest degradation with a first-order kinetic constant (k) of 0.0555, which is 1.49 times that of CeO₂/PBC-300 and 2.24 times that of CeO₂.This study innovatively elucidates the intrinsic polar components of biochar as effective modulators for optimizing OV configuration in CeO₂ and enhancing electrochemical performance, offering a novel and effective strategy for designing advanced carbon-supported metal oxide catalysts.