Rational modification by functional groups was regarded as one of efficient methods to improve the photocatalytic performance of graphitic carbon nitride (g-C3N4). Herein, g-C3N4 with yellow (Y-GCN) and brown (C-GCN) were prepared by using the fresh urea and the urea kept for five years, respectively, for the first time. Experimental results show that the H2 production rate of the C-GCN is 39.06 μmol/h, which is about 5 times of the Y-GCN. Meantime, in terms of apparent quantum efficiency (AQE) at 420 nm, C-GCN has a value of 6.3% and nearly 7.3 times higher than that of Y-GCN (0.86%). The results of XRD, IR, DRS, and NMR show, different from Y-GCN, a new kind of functional group of —N=CH— was firstly in-situ introduced into the C-GCN, resulting in good visible light absorption, and then markedly improving the photocatalytic performance. DFT calculation also confirms the effect of the —N=CH— group band structure of g-C3N4. Furthermore, XPS results demonstrate that the existence of —N=CH— groups in C-GCN results in tight interaction between C-GCN and Pt nanoparticles, and then improves the charge separation and photocatalytic performance. The present work demonstrates a good example of "defect engineering" to modify the intrinsic molecular structure of g-C3N4 and provides a new avenue to enhance the photocatalytic activity of g-C3N4 via facile and environmental-friendly method.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |