Synthesis of hollow donut-like carbon nitride for the visible-light-driven highly efficient photocatalytic hydrogen production and pollutants degradation
A hollow donut-like g-C3N4 (CMU-500) is prepared by controlling supramolecular polymer composed of cyanuric acid, melamine and urea at 500 °C calcination in air. CMU-500 has a large specific surface area of 92 m2/g, which is ten-fold higher than bulk g-C3N4. It exhibits high separation efficiency for photogenerated electron-hole pairs and high conductivity for interfacial charge transfer. CMU-500 exhibits a high visible light photocatalytic activity in the degradation of rhodamine B (k = 0.364 min-1) and reduction of Cr (VI) (k = 0.463 min-1), in which the rate constants k are more than 30 times superior to those of bulk g-C3N4. The hydrogen production efficiency of CMU-500 with co-catalyst Pt is as high as 2260 μmol g-1 h-1 under visible light irradiation, which is 180 times higher than bulk g-C3N4. An excellent stability of photocatalytic activity was observed in both of photocatalytic degradation and hydrogen production by four cycles of tests. Our results suggest a new strategy to design and synthesize high-effective photocatalysts toward to treatment of environmental pollution and hydrogen production.