Mesoporous Pt/La0.02Na0.98TaO3 nanocomposites as efficient photocatalyst for hydrogen evolution

Abstract

Mesoporous La0.02Na0.98TaO3 and Pt/La0.02Na0.98TaO3 at various Pt concentration (0.5–2 %) were synthesized through Pluronic F-127 Assisted sol-gel approach and the as-made materials were calcinated at 700 °C for 8 h. The obtained photocatalysts have been employed for the photocatalytic H2 evolution in the existence of glycerol as an electron donor. The TEM image of the mesoporous Pt/La0.02Na0.98TaO3 was well orderly orthorhombic-shaped morphology with smooth crystal surfaces with small particle size about 20−30 nm. XRD findings revealed that mesoporous La0.02Na0.98TaO3 and Pt/La0.02Na0.98TaO3 nanocomposites were properly indexed for structural orthorhombic. The surface area of mesoporous La0.02Na0.98TaO3 was determined around 220 m2 g−1; which reduced to 198 m2 g-1 with the introduction of 2%Pt into the pores. The H2 evolution over 1.5 % Pt/La0.02Na0.98TaO3 nanocomposite was greater 1350 times that mesoporous La0.02Na0.98TaO3 nanocomposite. The maximum H2 evolution rate over the 1.5 %Pt/La0.02Na0.98TaO3 nanocomposite was nearly 1094-fold higher than that the La0.02Na0.98TaO3 photocatalyst. The fabrication of mesoporous Pt/La0.02Na0.98TaO3 nanocomposites through a sol-gel assisted Pluronic F-127 template approach with small particle sizes, high crystallinity and large surface area are an efficient approach to promote H2 evolution. The enhancement of photocatalytic H2 evolution over mesoporous Pt/La0.02Na0.98TaO3 compared with La0.02Na0.98TaO3 were confirmed by photoelectrochemical and photoluminescence measurements. The reducibility and stability of the mesoporous Pt/La0.02Na0.98TaO3 nanocomposites can be employed as excellent photocatalysts in potential applications for H2 evolution.