2D g-C3N4as a bifunctional photocatalyst for co-catalyst and sacrificial agent-free photocatalytic N2fixation and dye photodegradation

Abstract

Photocatalytic N2fixation is an ecofriendly technology to produce ammonia. In this work, photocatalytic N2fixation to generate ammonia in the absence of any co-catalysts or sacrificial agents (SF) is achieved on 2D g-C3N4preparedviathermal exfoliation, for the first time. The formation of 2D g-C3N4is confirmed using several analytical techniques including XRD, SEM, TEM, FT-IR, and XPS analyses. 2D g-C3N4exhibits a blue shift in the bandgap compared to the bulk g-C3N4attributed to the quantum confinement effect. In the absence of SF, 2D g-C3N4shows an NH3production rate of 3.9 mg L−1h−1under sunlight irradiation, while no NH3is generated on bulk g-C3N4. In the presence of ethanol as a sacrificial agent, 2D g-C3N4also exhibits a higher NH3production rate (12.76 mg L−1h−1) than bulk g-C3N4(7.58 mg L−1h−1). Moreover, 2D g-C3N4shows superior photodegradation activity compared to bulk g-C3N4toward the decomposition of methylene blue (MB) and malachite green (MG) under sunlight irradiation. The enhanced photocatalytic activity of 2D g-C3N4could be attributed to its more exposed active sites, high charge separation, and low electron-hole recombination rate.