Rational construction of S-scheme Pt-MnO2/TiO2@Ti3C2Tx via Ti-O-Mn bond for distinguished charge transfer in photocatalytic wastewater environmental governance and hydrogen production

Exploring and adjusting the migration pathway of photogenerated electron-hole pairs in novel semiconductor composites is vital to enhance the charge separation efficiency and transferability in photocatalytic environmental governance and hydrogen generation performance. Herein, an electrostatic self-assembly combining with a low-temperature hydrothermal strategy for forming the Ti-O-Mn bond was designed to rationally construct the S-scheme Pt-MnO2/TiO2@Ti3C2Tx composite. Through the systematic characterization and density functional theory calculations, the metastable marginal Ti atoms and the electrostatic adsorbed Mn2+ ions on Ti3C2Tx surface are oxidized and in situ form TiO2/MnO2 nanoparticles (NPs) due to its fitted lattice energy and low adsorption energy, which are intercalated on the conductive Ti3C2Tx multilayer surfaces and construct a new-fashioned S-scheme TiO2/MnO2 heterojunction via the Ti-O-Mn bond, for affecting the density of charge states, promoting the charge separation and shortening migration carrier distance. Also, Pt NPs as the cocatalyst is selectively decorated on MnO2/TiO2@Ti3C2Tx surface for further improving the charge carrier transfer and visible light absorption. Benefiting from the extraordinary composition and structure, the obtained Pt-MnO2/TiO2@Ti3C2Tx composite exhibits high photocatalytic degradation of organic pollutants (more than 90%), hydrogen generation activity (3610 μmol g−1 h−1) and wonderful cycle stability.