Catalytic and Mechanistic Investigation of Polyaniline Supported PtO₂ Nanoparticles: A Combined <i>in situ</i>/<i>operando</i> EPR, DRIFTS, and EXAFS Study

Abstract

Compounds containing electrically conducting macromolecules bear interesting properties as functional materials in various fields. As for catalytic applications, however, principles are scarcely, if at all, understood. Here we describe a systematic investigation of the relationship between the structure of a new type of conducting polymer supported metal catalyst and the catalystʼs oxidation activity. We have found that nanoclusters of unusual β-PtO 2 ( d = (1.9 ± 0.5) nm) could be deposited on polyaniline, and the resulting catalyst exhibits exceptionally low light-off temperatures in carbon monoxide oxidation even in the presence of other environmental pollutants. Characterizing the working state of the active catalyst by combining in situ / operando techniques (EPR, DRIFTS, and EXAFS), we visualized a distinctly increased charge carrier density within the support. Our results suggest that the intensive contact between an electron-conducting polymer support and up-grown nanoparticles affords a charge exchange between redox centers, thereby boosting catalytic activity dramatically.