Engineering Si-bridge mediated g-C3N4/NdFeO3 Z-scheme heterojunction for multifunctional catalytic applications: CO2 conversion, organic pollutant degradation and H2 production

Environmental pollution and rapid consumption of energy and fuel resources are two major issues in the modern world. To address these issues, we engineered a silicate-bridged g-C3N4/NdFeO3 Z-scheme nanocomposite and used it for photocatalytic CO2 conversion, 2,4-DCP degradation, and methanol-assisted H2 evolution. Compared to NdFeO3 and g-C3N4 nanoparticles, the NdFeO3 and g-C3N4 nanosheets, respectively, have larger surface areas, developed morphologies, enhanced charge separation, and improved photocatalytic performance. Remarkably, the introduction of g-C3N4 nanosheets into NdFeO3 nanosheets (NFONS) effectively optimizes the band gap position, promotes charge separation through a Z-scheme electron-transfer mechanism, enlarges the surface area, and improves photocatalytic efficiency. In addition, the silicate (Si-O) bridge served as an electronic bridge charge-transfer facilitator, resolved lattice mismatch, and enhanced photocatalytic efficiency by modulating photoelectrons. Compared with pristine NFONS, the optimized 5CNNS-1.5Si/NFONS nanocomposites delivered a 14.17-fold improvement in CO2 conversion activity, a 7.25-fold increase in photocatalytic 2,4-DCP degradation, and a 2.64-fold increase in methanol-assisted H2 generation. Scavenger experiments and the photocatalytic pollutant degradation mechanism confirmed that photogenerated holes (h+) and superoxide radicals (•O2-) are the dominant reactive species that initiate the photocatalytic activities. Our findings offer valuable insights into the design of Z-scheme nanocomposites and their employment for multifunctional photocatalytic applications.