Plasma Ag-Modified α-Fe₂O₃/g-C₃N₄ Self-Assembled S-Scheme Heterojunctions with Enhanced Photothermal-Photocatalytic-Fenton Performances

Abstract

Low spectral utilization and charge carrier compounding limit the application of photocatalysis in energy conversion and environmental purification, and the rational construction of heterojunction is a promising strategy to break this bottleneck. Herein, we prepared surface-engineered plasma Ag-modified α-Fe2O3/g-C3N4 S-Scheme heterojunction photothermal catalysts by electrostatic self-assembly and light deposition strategy. The local surface plasmon resonance effect induced by Ag nanoparticles broadens the spectral response region and produces significant photothermal effects. The temperature of Ag/α-Fe2O3/g-C3N4 powder is increased to 173 °C with irradiation for 90 s, ~3.2 times higher than that of the original g-C3N4. The formation of 2D/2D structured S-Scheme heterojunction promotes rapid electron-hole transfer and spatial separation. Ternary heterojunction construction leads to significant enhancement of photocatalytic performance of Ag/α-Fe2O3/g-C3N4, the H2 photocatalytic generation rate up to 3125.62 µmol g−1 h−1, which is eight times higher than original g-C3N4, and the photocatalytic degradation rate of tetracycline to reach 93.6%. This thermally assisted photocatalysis strategy improves the spectral utilization of conventional photocatalytic processes and provides new ideas for the practical application of photocatalysis in energy conversion and environmental purification.

Keywords

• S-Scheme heterojunction
• photothermal effect
• 2D/2D structure
• surface plasmon resonance
• photocatalytic-Fenton