G-C3N4 tubes decorated with MnMoO4<middle dot>H2O: Outstanding S-scheme photocatalyst for detoxification of water pollutants upon visible light

Recently, the utilization of heterogeneous photocatalysts has been proposed as an effective solution for environmental purification, as one of the solar energy conversion processes, under mild conditions. In this research, MnMoO4<middle dot>H2O nanoparticles were anchored on tubular g-C3N4 (abbreviated as TGCN) by a one-pot hydrothermal route. The phase structure, electronic environment, spectroscopic characteristics, composition, morphology, surface area, and electrochemical properties of the resultant materials were explored using XRD, XPS, EDX, FESEM, HRTEM, FTIR, PL, photocurrent, EIS, and BET analyses. The photocatalytic activity of TGCN/MnMoO4<middle dot>H2O (20 %) nanocomposite was 4.25, 5.36, 9.07, 12.4, and 8.84 times better than modified GCN, and 3.91, 2.77, 6.24, 10.9, and 6.82 times higher than MnMoO4<middle dot>H2O in removals of tetracycline, rhodamine B, methylene blue, methyl orange, and fuchsine pollutants, respectively. The improved visible-light absorption and rapid charge migration/separation between TGCN and MnMoO4<middle dot>H2O counterparts through S-scheme heterojunction route were the key reasons for the boosted photocatalytic performance. The biocompatibility of solution after decomposition of tetracycline via the growth of wheat seeds was verified. Finally, the stability of the binary TGCN/MnMoO4<middle dot>H2O (20 %) heterostructure was measured by the stability test after four reuses.