Bismuth vanadate (BiVO4) is a common photocatalyst for water remediation, yet its powder form renders difficulty to disperse, recycle and regenerate, limiting photodegradation efficiency. In this study, a lignocellulosic-templated BiVO4 photocatalyst was fabricated from BiVO4 precursor and lignocellulose using a simple vacuum impregnation (w/o heat treatment on wood template). Results showed that the modified template retained original hierarchical structure with an increased specific surface area and reduced hemicellulose content, leading to a promising template for uniform distribution of BiVO4. Moreover, compared to untreated, heat treatment cleaved acetyl groups in the hemicellulose chain, broke down fatty ether bonds, and oxidized lignin side chains, resulting in no disruption to the catalysis of BiVO4. The BiVO4-pyrolyzed lignocellulosic photocatalyst achieved remarkable degradation efficiencies of 90.03 % (approximately 7-fold increase compared to untreated) for RhB, and complete degradation of Cr (VI) within 60 min. Furthermore, the efficiency remained >80 % after seven cycles. The mechanism was hypothesized that BiVO4 and template play distinct roles, as deoxygenated lignocellulosic template only acts as a carrier for BiVO4 growth, and BiVO4 serves as the photocatalyst. However, untreated template can react with BiVO4 and impair photocatalytic efficiency. The BiVO4-pyrolyzed lignocellulosic photocatalyst hold great promise for the remediation of aqueous contaminants.
Keywords: Bismuth vanadate; Lignocellulosic substrate; Photocatalysis.
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