The role of adsorbed oxygen in formic acid oxidation by Pt/TiO2 facilitated by light pre-treatmentElectronic supplementary information (ESI) available: Fig. S1-S4 containing TEM image of Ptox/TiO2; effect of Pt oxidation states on the formic acid oxidation rate prior to and following light pre-treatment; effect of initial formic acid loading on dissolved oxygen consumed during formic acid oxidation by Pt/TiO2; deconvolution of XPS with different dissolved oxygen concentration prior to formic aci

• Main Authors: Saputera, Wibawa H, Scott, Jason, Ganda, Nathania, Low, Gary K.-C, Amal, Rose
• Format: Journal Article
• Published: 22.08.2016
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/c6cy00939e

Our study demonstrates that adsorbed oxygen species on Pt surfaces (PtO ads ) and active oxygen species (O − ads ) play a critical role in formic acid oxidation under the ambient condition in an aqueous suspension. The impact of light pre-treatment and dissolved oxygen concentration on the generation of surface oxygen species (PtO ads and O − ads ) was studied using X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). A strong correlation between the formic acid oxidation rate and the surface oxygen species was observed. Light pre-treatment introduced a greater amount of PtO ads and O − ads compared with the untreated Pt/TiO 2 and, as a result, invoked an almost seven-fold increase in the formic acid oxidation rate. The amount of surface oxygen species was found to increase with increasing dissolved oxygen concentration in the system which also accelerated the formic acid oxidation rate. Additionally, the decreasing amount of PtO ads at the end of the reaction with increasing initial formic acid concentration suggests that the oxygen species are important to, and consumed during, the oxidation process. The formic acid oxidation rate by Pt/TiO 2 under the ambient condition strongly depends on the presence of surface active oxygen species (PtO ads and O − ads ).