Unveiling the enhanced selectively photocatalytic degradation for polyphenolic component of Chinese pharmaceutic wastewater by Bi2MoO6/ pBC/g-C3N4 S-scheme heterojunction: DFT calculations and mechanism insights

This study introduces a novel Bi2MoO6/pBC/g-C3N4 (BMO/pBCN) S-scheme heterojunction for the selective photocatalytic degradation of organic wastewater. The 3-BMO/pBCN heterojunction exhibits significant potential for targeting polyphenolic compounds, such as chlorogenic acid, in real pharmaceutical wastewater. Approximately 48.27 % of chlorogenic acid is efficiently degraded under 120 min of visible light irradiation, achieving 1.57 and 2.76 times higher degradation rates than g-C3N4 and Bi2MoO6, respectively. DFT calculations indicate that the selective degradation mechanism is driven by the differential adsorption energy between the components and the catalyst. Enhanced photocatalytic performance and degradation efficiency were further investigated using optoelectronic characterization, HPLC-MS, ESR and trapping experiments. The primary active species in the 3-BMO/pBCN heterojunction include center dot O2-, center dot OH, and 1O2. The charge transfer mechanism within the BMO/pBCN heterojunction aligns with the S-scheme, as confirmed by DFT calculations and optoelectronic analyses. This work provides valuable insights for designing g-C3N4-based heterojunctions with high selectivity for pharmaceutical wastewater purification.