Effects of Metal Ions on H₂ Generation during Photolysis of Suspended TiO₂ in Aqueous Systems
Pages 63-71
G.R. Dey

DOI: http://dx.doi.org/10.6000/1929-5030.2015.04.01.5

Published: 25 Feburary 2015

Abstract: Nowadays, photocatalysis is being applied as a promising technique for decontamination, purification, deodorization, etc. of polluted air and wastewaters. This technique attempts also to generate renewable and non-polluting fuels utilizing various carbon and hydrogen sources. In this context, studies on photo-catalytic generation of H₂ using 0.1% w/v TiO₂ photo catalyst as a suspension in water was carried out using 350 nm light. This was explored further in presence of various metal ions such as Ag⁺, Cu²⁺, Fe²⁺, Au³⁺ and V⁵⁺ at different ambient such as air and CO₂, in presence of a hole scavenger (2-propanol and formic acid). H₂ yields in CO₂-purged systems as analyzed in GC-TCD were reasonably higher, and increased further when metal ions were added into the systems. Based on H₂ yields, HCOOH was found to be a more supportive hole scavenger as compared to 2-propanol in metal ions containing systems. Besides the formation of low to high concentrations of various gaseous products, nanoparticles of gold, silver and copper were also observed as photolysis products. This indicated that the presence of both reduced metal ions and their in-situ generated nanoparticles at various stages either in the free/unbound and/or associated with TiO₂ photocatalyst in aqueous systems, together play a significant role in enhancing the H₂ yields.