Synthesis of salicylic acid-modified graphite carbon nitride for enhancing photocatalytic nitrogen fixation.

Finding an efficient and environment-friendly photocatalyst is significant for photocatalysis. In this research, a simple calcination with urea and salicylic acid (SA) is created for constructing a SA-modified graphite carbon nitride (g-CN-SA) photocatalyst. Compared to pure g-CN, g-CN-SA presents broadened light absorption, due to n → π* transition at nitrogen atoms. Interestingly, SA modification can strongly affect chemical and physical properties of g-CN, including increasing Brunauer-Emmett-Teller (BET) specific area, forming porous structure, improving optical absorption and promoting carrier separation, thus achieving the improved photocatalytic activity of g-CN-SA. The optimum g-CN-SA with the mass of SA 0.05 g (g-CN-SA-0.05) presents a high ammonia evolution rate of 7.92 mmol Lh g, 2.5 and 1.4 times than g-CN (3.2 mmol Lh g) and g-CN loaded with Pt (5.47 mmol Lh g). Furthermore, the excellent photostability of g-CN-SA is also achieved.