3D macropore carbon-vacancy g-C3N4 constructed using polymethylmethacrylate spheres for enhanced photocatalytic H2 evolution and CO2 reduction

Metal-free g-C3N4 is widely used in photocatalytic reactions owing to its suitable band structure. However, it has low specific surface area and insufficient absorbance for visible light, and its photoexcited carriers have high recombination rates. In this study, the 3D macropore C-vacancy g-C3N4 was prepared through a facile one-step route. Polymethylmethacrylate is used as a template to increase the surface reaction sites of g-C3N4 and extend its visible-light range. Compared to unmodified g-C3N4, the H2 production and CO2 reduction rates of the fabricated g-C3N4 significantly improved. The special pore structure significantly improved the light utilization efficiency of g-C3N4 and increased the number of surface-active sites. The introduction of C-vacancy extended the absorption band of visible-light and suppressed the carrier recombination. The newly developed synthesis strategy can improve solar energy conversion efficiency and potentially modifies g-C3N4.