Controllable fabrication of a red phosphorus modified g-C3N4 photocatalyst with strong interfacial binding for the efficient removal of organic pollutants

The development of low-cost and efficient photocatalysts is pursued to promote the large-scale application of photocatalysis in environmental remediation. In this study, cost-effective g-C3N4-RP (red phosphorus) heterostructures were controllably fabricated, in which sodium hypophosphite was utilized as a new phosphorus source. The formed RP exhibited a particle morphology with the size of 60–100 nm. These nanoparticles were strongly bonded to the g-C3N4 surface by forming P-N chemical bonds. When compared with pristine g-C3N4, the as-synthesized g-C3N4-RP hybrids exhibited synergistically improved adsorption and photocatalytic activity for the removal of Rhodamine B (RhB) pollutant in aqueous solution. The improved adsorption for g-C3N4-RP resulted from the higher surface area, presence of the manufactured larger delocalized system, and more negatively charged surface when RP was introduced. Meanwhile, the improved performance of the photocatalysis was a result of the strengthened light adsorption, improved separation and transfer of photogenerated electron-hole pairs, and efficient surface reaction. A typical Type II heterostructure was confirmed to be formed at the interface to accelerate the charge carrier transfer between g-C3N4 and RP. The h+ and •O2⁻ radicals were determined to be the major oxide species for RhB degradation. Finally, a possible RhB degradation mechanism was revealed in the g-C3N4-RP photocatalytic system. We believe that this study is of importance to accelerate the development of low-cost and effective catalysts for wastewater remediation by photocatalysis.