Porous carbon nitride (P-C₃N₄) was prepared by one-step urea calcination. Its hierarchical porous structure and defects boost visible light and enhance mass transfer. This catalyst exhibits 44% longer carrier lifetime than bulk C₃N₄ and can be easily scaled up and demonstrates excellent catalytic reactivity in various types of cross-dehydrogenative coupling (CDC) reactions under visible light irradiation. A very high reaction rates of 6467 and 10,625 μmolg⁻¹h⁻¹ were achieved by P-C₃N₄ in model reaction of aza-Henry type and Mannich type of CDC reaction, which are 26.8 and 2.8 times higher than previous reports, respectively. Moreover, P-C₃N₄ can maintain 95% yield of target product in aza-Henry CDC reaction after 21 cycles of repeated experiments.

Cost-effective and efficient photocatalysis is highly desirable in chemical synthesis. Here a honeycomb-like porous carbon nitride (P-C₃N₄) with defects was prepared by a simple one-step calcination of an aqueous urea solution. By introducing the hierarchical porous structure and defects, the P-C₃N₄ was able to make more efficient use of visible light and enhance mass transfer. This catalyst exhibits 44% longer carrier lifetime than bulk C₃N₄ and can be easily scaled up and demonstrates excellent catalytic reactivity in various types of cross-dehydrogenative coupling (CDC) reactions under visible light irradiation. A very high reaction rates of 6467 and 10,625 μmolg⁻¹h⁻¹ were achieved by P-C₃N₄ in model reaction of aza-Henry type and Mannich type of CDC reaction, which are 26.8 and 2.8 times higher than previous reports, respectively. Moreover, P-C₃N₄ can maintain 95% yield of target product in aza-Henry CDC reaction after 21 cycles of repeated experiments. Our low-cost, easy-to-process, and highly efficient C₃N₄ photocatalyst is expected to bring new insights in chemical synthesis.