Spatial separation of photo-generated carriers in g-C3N4/MnO2/Pt with enhanced H2 evolution and organic pollutant control

The low utilization of visible light and quick recombination of photo-generated electron–hole pairs of g-C3N4 hinder the enhancement of its photocatalytic performance. Modification of g-C3N4 with dual cocatalysts can promote the spatial separation of carriers, thus showing good redox ability. Here, the efficient photocatalyst g-C3N4/MnO2/Pt with dual cocatalysts is prepared in two steps including calcination- and photo-deposition process. Pt and MnO2 nanoparticles are used as electron and hole collectors, respectively. The g-C3N4/MnO2/Pt composite is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). Compared with pure g-C3N4, the photocatalytic hydrogen (H2) evolution performance of g-C3N4/MnO2/Pt is significantly enhanced. And the H2 production yield of g-C3N4/MnO2/Pt is more than 8 times as high as that of g-C3N4/Pt. Meanwhile, the prepared photocatalyst can help promoting peroxymonosulfate activation to degrade organic pollutants. Its degradation performances for phenol, sulfadiazine, bisphenol A, Rhodamine B, and methyl orange are significantly improved, owing to the generation of reactive oxygen species. This work provides a new strategy for the application of photo-generated electrons of g-C3N4 with dual cocatalyst in H2 evolution and environmental remediation. Graphic abstract