Investigation of La-BiVO 4 /g-C 3 N 4 photocatalytic system for efficient removal of hazardous water contaminants

The application of semiconductor photocatalysis powered by renewable energy sources for environmental remediation of emerging contaminants has gained significant research interest in recent years. Lanthanum-substituted bismuth vanadate (La-BiVO4)/graphitic carbon nitride (g-C3N4) heterojunctions were synthesized for the photocatalytic degradation of emerging water contaminants. Significantly, La³+ substitution serves as a model system for exploring the broader concept of cationic substitutions on BiVO4. By strategically replacing a portion of Bi(III) with various cations, we can potentially tailor the electronic structure of BiVO4 for enhanced photocatalytic performance. Photoelectrochemical analysis confirmed rapid charge separation and reduced resistance, leading to effective contaminant degradation. The La-BiVO4/g-C3N4 nanocomposite exhibited exceptional photocatalytic performance under simulated solar light irradiation (Xe-350W, AM 1.5 G), achieving 87.66% photooxidation of roxarsone within 150 min, surpassing g-C3N4, BiVO4, LaVO4, La-BiVO4, BiVO4/g-C3N4, and LaVO4/g-C3N4 by factors of 1.94, 1.26, 2.25, 1.39, 1.13, and 2.51, respectively. Moreover, it demonstrated 99.61% degradation of Cr(VI) after 60 min, outperforming g-C3N4, BiVO4, LaVO4, La-BiVO4, BiVO4/g-C3N4, and LaVO4/g-C3N4 by factors of 1.11, 1.81, 1.62, 1.67, 1.20, and 1.13, respectively. These findings underscore the superior photocatalytic efficacy of the La-BiVO4/g-C3N4 nanocomposite. The efficient photocatalytic activity of La-BiVO4/g-C3N4 type-II heterojunctions demonstrates its potential for real-world environmental remediation. This material offers a promising strategy for removing harmful water contaminants, thereby mitigating risks associated with water consumption.