Porous defective carbon nitride obtained by a universal method for photocatalytic hydrogen production from water...

For the first time, herein this work, we have developed an effective and adaptable method to introduce defects onto the polymeric carbon nitride by simply grinding urea with urea nitrate which resulting new carbon nitride composite (UNU-C₃N₄) and melamine with urea nitrate which resulting new carbon nitride composite (UNM-C₃N₄). The UNU-C₃N₄ reveals high performance towards photocatalytic hydrogen production and as well as photocatalytic removal of contaminants. The results confirm that the defects enhanced the specific surface area, and improved performance of adsorbed oxygen which beneficial to generate more active radicals and more conducive sties to improve d the overall photocatalytic performance. The high N, H, and O content-enhanced electron polarization effects, by introducing the additional N, H, and O atoms into the g-C₃N₄ matrix, which will increase the charge transfer rate and charge separation efficiency. At the same time, the results of ESR also expression that the new type of as-prepared carbon nitride samples exhibit abundant of hydrogen radical (H) formation, which is also assist to improve the photocatalytic hydrogen production performance. As expected, the H₂ evolution rate of UNU-C₃N₄(or UNM-C₃N₄) underneath simulated solar light irradiation is 9.93 times (13.76 times) than that of U-C₃N₄ (urea as raw material) (or M-C₃N₄ (melamine as raw material)). The high hydrogen evolution rates of UNU-C₃N₄ and UNM-C₃N₄ are 830.94 and 556.79 μmol g^-1  h^-1 under the visible-light irradiation, respectively. Meanwhile, the synthesized UNU-C₃N₄ and UNM-C₃N₄ material are demonstrated an efficient ability to degrade pollutants. In general, this work provides a viable way to introduce defects and hydrogen bands into the structure of carbon nitride.