Photoreforming of 2-methyl-2-butanol over bare and Pt-loaded TiO₂: mechanistic insights & product selectivity under ambient conditions

Title : Photoreforming of 2-methyl-2-butanol over bare and Pt-loaded TiO₂: mechanistic insights & product selectivity under ambient conditions

Abstract:

Photoreforming of tertiary alcohols has emerged as a promising approach for sustainable hydrogen production because it simultaneously generates hydrogen and value-added oxidation products under ambient conditions1,2. Unlike primary alcohol systems, tertiary alcohol photoreforming can proceed over bare TiO₂, enabling the intrinsic photocatalytic activity of different TiO₂ polymorphs to be evaluated; nonetheless, incorporation of noble metal co-catalysts result in significantly higher reaction rates in primary alcohol systems3. Despite knowledge on primary alcohol photoreforming, the influence of TiO₂ polymorphs, and Pt co-catalyst loading on the photoreforming of tertiary alcohols has not been systematically investigated. This study presents one of the first systematic investigation of the liquid-phase photoreforming of 2-methyl-2-butanol over bare and Pt-loaded TiO₂ under ambient conditions. The photocatalytic activity of bare anatase, rutile and P25 TiO₂ polymorphs were evaluated, followed by a systematic investigation into the effect of Pt loading on hydrogen production, and product selectivity.

Among the bare photocatalysts, P25 exhibited the highest photocatalytic activity, followed by anatase, and rutile. The introduction of Pt co-catalysts resulted in hydrogen evolution to occur, confirming its role in promoting the recombination of surface hydrogen species, and supported the applicability of the proposed single-photon reaction pathway for liquid-phase tertiary alcohol photoreforming4. Increasing the Pt loading further improved hydrogen production; however, hydrogen selectivity remained relatively low, indicating that competing oxidation pathways continued to influence the overall product distribution. This work provides the first comprehensive comparison of TiO₂ polymorphs and Pt loadings for the photoreforming of tertiary alcohol photoreforming systems, and provides guidance for the rational design of photocatalysts for sustainable hydrogen production systems.

Biography:

I am a Chemical Engineering researcher and PhD candidate at Stellenbosch University, South Africa. My research focuses on solar-driven hydrogen production using heterogeneous photocatalysis, with particular interest in TiO₂-based photocatalysts and the development of low-cost alternatives to platinum. My work investigates the synthesis, characterisation, and photocatalytic performance of copper and platinum loaded TiO₂ systems, as well as alcohol photoreforming and the mechanisms governing hydrogen evolution. I have conducted international research at the Technical University of Munich, Germany, through a DAAD-supported research stay. I have also received several academic awards for excellence and have published research in the field of hydrogen production.