Synthesis, photocatalytic, and photoelectric performance of mesoporous Au/TiO2 and Au/TiO2/MWCNT nanocomposites

This study explores the photocatalytic and photoelectric performance of ternary Au/TiO₂/MWCNT nanocomposites. XRD, TEM, XPS, and UV–Vis analyses verify the effective dispersion of TiO₂ and Au nanoparticles within the MWCNT matrix. Under UV irradiation, the optimized Au/TiO₂/MWCNT composite exhibits a substantial enhancement in the catalytic performance compared to pure TiO₂ nanoparticles. This enhancement stems from extended visible-light absorption, minimized electron-hole recombination, and effective charge transfer mechanisms facilitated by Au particles and MWCNTs. The optimized composite achieves a 2.7-fold increase in the methylene blue (MB) photo-degradation rate constant relative to pure TiO₂, with 87 % MB degradation after 120 min of UV irradiation. Additionally, the photoelectric conversion efficiency of dye-sensitized solar cells increases from 1.26 % for pure TiO₂ to 3.37 % for the Au/TiO₂/MWCNT composite. These improvements are attributed to enhanced interfacial charge transport, increased specific surface area, reduced band gap energy, and the plasmonic effect of Au particles. PL and EIS measurements support the proposed charge mechanism and confirm the improved carrier density in the Au/TiO₂/MWCNT composites. These findings highlight the potential of Au/TiO₂/MWCNT composites for advanced photocatalytic and photovoltaic applications.