Enhanced H2 evolution via photocatalytic water splitting using mesoporous TiO2/RuO2/CuO ternary nanomaterial

Abstract

Mesoporous TiO2/RuO2/CuO (0.05, 0.1, 0.5, and 1%) ternary nanosystem have been synthesized via sol-gel route using pluronic P123 as structure directing agent. The diffuse reflectance spectra (DRS) indicated a considerable red shift for mesoporous TiO2/RuO2/CuO 1% nanomaterial with a band gap energy value of 2.5 eV compared to 2.9 eV for mesoporous TiO2/RuO2 0.5%. The N2 sorption studies using BET (Brunauer Emmet Teller) revealed the type IV adsorption isotherms for the prepared samples with H3 type hysteresis loop establishing the formation of mesoporous structure. The specific surface area of mesoporous TiO2/RuO2/CuO 1% and TiO2/RuO2 0.5% were 53 and 39.5 m2/g, respectively. The X-ray photoelectron spectroscopic analysis of the ternary material mesoporous TiO2/RuO2/CuO 1% confirmed the existence of Ru, Cu, O, and Ti in this material which was further supported through high resolution transmission electron microscopic (HR-TEM) and energy dispersive x-ray spectroscopic (EDS) studies. From PL spectra it followed that there was a substantial reduction in PL intensity of the ternary nanomaterial TiO2/RuO2/CuO 1% compared to mesoporous TiO2 and mesoporous TiO2/RuO2 0.5%, which confirmed the lower electron-hole recombination in this ternary nanomaterial, which was further supported through photocatalytic H2 evolution studies using these catalysts. From the comparative photocatalytic H2 evolution conducted using the catalysts mesoporous TiO2/RuO2/CuO 1% (0.05, 0.1, 0.5 and 1%), mesoporous TiO2/RuO2 0.5%, and mesoporous TiO2, the maximum H2 evolution was observed with mesoporous TiO2/RuO2/CuO 1%. The H2 evolution was monitored by varying various parameters such as effect of catalyst used, catalyst weight, concentration of CuO loaded, amount of sacrificial agent, chain length of alcohols as sacrificial agent, and found remarkable influence in hydrogen generation. Continuous irradiation of the photocatalyst mesoporous TiO2/RuO2/CuO 1% for 18 hours resulted in the maximum evolution of 20.7 mmol of H2. The present study demonstrated the excellent photocatalytic performance of the newly synthesized catalyst, mesoporous TiO2/RuO2/CuO ternary nanomaterial.