Abstract
Photocatalytic N-2 fixation is an ecofriendly technology to produce ammonia. In this work, photocatalytic N-2 fixation to generate ammonia in the absence of any co-catalysts or sacrificial agents (SF) is achieved on 2D g-C3N4 prepared via thermal exfoliation, for the first time. The formation of 2D g-C3N4 is confirmed using several analytical techniques including XRD, SEM, TEM, FT-IR, and XPS analyses. 2D g-C3N4 exhibits a blue shift in the bandgap compared to the bulk g-C3N4 attributed to the quantum confinement effect. In the absence of SF, 2D g-C3N4 shows an NH3 production rate of 3.9 mg L-1 h(-1) under sunlight irradiation, while no NH3 is generated on bulk g-C3N4. In the presence of ethanol as a sacrificial agent, 2D g-C3N4 also exhibits a higher NH3 production rate (12.76 mg L-1 h(-1)) than bulk g-C3N4 (7.58 mg L-1 h(-1)). Moreover, 2D g-C3N4 shows superior photodegradation activity compared to bulk g-C3N4 toward the decomposition of methylene blue (MB) and malachite green (MG) under sunlight irradiation. The enhanced photocatalytic activity of 2D g-C3N4 could be attributed to its more exposed active sites, high charge separation, and low electron-hole recombination rate.