In situ construction of oxygen deficient MoO_3-x nanosheets/porous graphitic carbon nitride for enhanced photothermal-photocatalytic hydrogen evolution

In this work, the photocatalysts containing oxygen-deficient molybdenum oxide and macroscopic three-dimensional porous graphitic carbon nitride phase composite (MoO_3-x/PCN) were prepared by in situ self-assembly method. The crystal phase and structure were characterized by XRD, XPS, FT-IR, SEM, and TEM measurements. Hydrogen production results showed that introducing of MoO_3-x resulted in a higher hydrogen production rate of MoO_3-x/PCN composite catalyst than that of PCN. Among them, the highest hydrogen production rate of 2336.15 μmol g⁻¹ h⁻¹ was achieved for MoO_3-x-10/PCN, which was 2.23 times higher than PCN (1048.00 μmol g⁻¹ h⁻¹). When the reaction system temperature was 100 °C, the photothermal hydrogen production rate of MoO_3-x-10/PCN was 8902.00 μmol g⁻¹ h⁻¹, which was 3.81 times higher than that at room temperature. PL spectra, UV–vis spectra and photoelectrochemical measurements showed that the localized surface plasmon resonance (LSPR) effect of MoO_3-x effectively enhanced the photo response range and increased the temperature of the reaction system. ESR measurements showed that he composites should follow the Z-scheme charge transfer mechanism, the electrons in the CB of MoO_3-x further migrate to the VB of PCN, which hinders the charge complexation in MoO_3-x and PCN, improving the hydrogen production activity. This study provides a new idea for constructing a plasma-based photothermal synergistic catalytic hydrogen production strategy.