Enhanced photocatalytic activity in H2 production from methanol aqueous solution based on the synthesized Pt-TiO2-decorated MoSe2 nanocomposites

Abstract

In this work, a simple hydrothermal method to synthesize a ternary nanocomposite of Pt-TiO2 decorated on MoSe2 as a photocatalyst for hydrogen (H2) evolution from an aqueous methanol solution. The-as prepared Pt-TiO2/MoSe2 nanocomposite were characterized by XRD, Raman spectra, electron microscopy (FE-SEM/Mapping and HR-TEM), XPS UV-Vis and PL analysis. XRD patterns confirmed the presence of MoSe2 and Pt-TiO2 crystal phases in the Pt-TiO2/MoSe2 nanocomposite. Raman spectra displayed characteristic peaks corresponding to Mo-Se out-of-plane vibration and Pt-TiO2 vibration modes, confirming the successful synthesis of Pt-TiO2/MoSe2 nanocomposite. FE-SEM images showed a sheet-like morphology for MoSe2-NS and spherical Pt/TiO2 particles, with MoSe2 sparsely scattered on the Pt-TiO2 surface with EDS mapping confirmed even element distribution of Pt-TiO2/MoSe2 nanocomposite. TEM images revealed the transparent nature of MoSe2-NS with well-resolved lattice fringes. Pt-TiO2 exhibited uniform dispersion of Pt nanoparticles on TiO2, and the Pt-TiO2/MoSe2 nanocomposite showed integration of MoSe2-NS with Pt-TiO2. HRTEM images confirmed the lattice fringes of MoSe2-NS, Pt, and TiO2 particles. Tauc plot measurements revealed optical band gaps of 2.99 eV for MoSe2-NS, 3.19 eV for Pt-TiO2, and 2.78 eV for Pt-TiO2/MoSe2. XPS analysis confirmed the presence of Mo, Se, Pt, Ti, O, and C elements in the Pt-TiO2/MoSe2 nanocomposite. Based on the photoelectrochemical measurements, the Pt-TiO2/MoSe2 nanocomposite show the lower onset overpotential of 123 mV, which is much higher than Pt-TiO2 (179 mV) and MoSe2 (213 mV) at 10 mA/cm2. The photocatalytic efficiency of Pt-TiO2/MoSe2 nanocomposite in the context of H2 production through the enhancement of aqueous methanol under visible light exposure was assessed across different factors. Among these, the Pt-TiO2/MoSe2 nanocomposite exhibited the highest photoactivity in H2 production at 1337 μmolg−1 after 4 h. These results show the promising potential of the Pt-TiO2/MoSe2 nanocomposite catalyst in addressing both environmental and energy challenges in the future.