Ti3C2 MXene embellished g-C3N4 nanosheets for improving photocatalytic redox capacity

•The Ti3C2/g-C3N4 schottky junctions are obtained via ultrasound vibration process.•The intimate interfacial structure of Ti3C2/g-C3N4 avails to photoinduced charge transfer.•Improved photocatalytic N2 fixation, CO2 reduction, and levofloxacin degradation were confirmed.•The enhanced photocatalytic redox properties are consequences of multiple factors. The Ti3C2/g-C3N4 schottky junctions were fabricated by a facile ultrasound method and improved photocatalytic reduction of N2 and CO2 as well as degradation of antibiotic levofloxacin were confirmed. [Display omitted] The development of efficient photocatalyst is critical for the practical application of photocatalysis. Herein, Ti3C2 MXenes, a kind of 2D-layered material, is successfully coupled with g-C3N4 sheets under ultrasound irradiation. A series of characterization methods are adopted for the investigation of the obtained samples. The consequences reflect that for the successful formation of 2D/2D schottky junction and a new Ti-N bond between g-C3N4 and Ti3C2. Moreover, photocatalytic measurements demonstrate Ti3C2 MXenes is an efficient activator for g-C3N4 to promote its photocatalytic reactivity. The photocatalytic fixation of N2 tests manifest that the optimized sample of TC-CN-1 (g-C3N4 with the 1 wt% Ti3C2 MXene loading) shows the highest generation yield of NH4+ (601 umol L-1·gcat-1·h-1), which is 3.64-fold higher than that of pristine g-C3N4 (203 umol L-1·gcat-1·h-1). Furthermore, the Ti3C2/g-C3N4 show superior photocatalytic conversion of CO2 to CO or CH4 yields than that of g-C3N4. Besides, the photocatalytic degradation measurements show that only 33.6% of levofloxacin can be decomposed by pristine g-C3N4, while the removal ratio of levofloxacin reaches 72% for g-C3N4 with 1 wt% loading of Ti3C2 MXene under visible light illumination for 30 min. The photocatalytic improvements are confirmed to benefit from the faster separation of photo-generated electrons and holes, higher light response ability, and more active sites. This study demonstrates that Ti3C2/g-C3N4 schottky junction is a promising photocatalyst for the photocatalytic nitrogen fixation, and antibiotics degradation.