Dual strategy for enhanced photocatalytic degradation of tetracycline: Phosphorus doping and cobalt boride co-catalyst loading on g-C3N4

Despite being promising for the removal of ever-growing pharmaceutical contamination from water, the g-C3N4 photocatalyst still faces roadblocks to implementation due to its intrinsic properties, for example, the limited visible light absorption, reduced charge separation capacity, and low mobility of photo-excited electrons. Doping with non-metals and loading with the co-catalyst is an effective approach to overcome the abovementioned limitations for the g-C3N4 photocatalyst. Herein, both these strategies are integrated in cobalt-boride loaded on phosphorous-doped g-C3N4 (CoB/P-g-C3N4) by facile chemical fabrication routes. Detailed morphological, structural, chemical, and spectroscopic analyses demonstrated that phosphorus doping effectively reduces the bandgap of g-C3N4 to absorb more visible light. Uniformly distributed CoB-nanoparticles create local Schottky barriers that trap photo-generated electrons from g-C3N4 to suppress charge carrier recombination. The optimized CoB/P-g-C3N4 photocatalyst produces ~35 times higher degradation rate constant than the pristine g-C3N4 for the photocatalytic removal of tetracycline antibiotics from water under visible light irradiation. Combining these advantageous features with cost-effective and stable elements, CoB/P-g-C3N4 offers an optimal solution for tuning the intrinsic electronic structure and surface reactivity of g-C3N4, making it highly effective for various photocatalytic applications.