Active Site-Directed Tandem Catalysis on Single Platinum Nanoparticles for Efficient and Stable Oxidation of Formaldehyde at Room Temperature.

Abstract

The application of tandem catalysis is rarely investigated in degrading organic pollutants in the environment. Herein, a tandem catalyst on single platinum (Pt) nanoparticles (Pt0 NPs) is prepared for the sequential degradation of formaldehyde (HCHO) to carbon dioxide gas [CO2(g)] at room temperature. The synthesis approach includes coating of uniform Pt NPs on SrBi2Ta2O9 platelets using a photoreduction process, followed by calcination of the sample in the atmosphere to tune partial transformation of Pt0 atoms to Pt2+ ions in the tandem catalyst. The conversion of HCHO to CO2(g) is monitored by in situ Fourier transform infrared spectroscopy, which shows first conversion of HCHO to CO32- ions onto Pt0 active sites and subsequently the conversion of CO32- ions to CO2(g) by neighboring Pt2+ species of the catalyst. The later process with Pt2+ species does not allow CO32- poisoning of the catalyst. The enhanced activity of the prepared tandem catalyst to oxidize HCHO is maintained continuously for 680 min. Comparatively, the catalyst without Pt2+ shows activity for only 40 min. Additionally, the tandem catalyst presented herein performs better than the Pt/titanium dioxide (TiO2) catalyst to degrade HCHO. Overall, the tandem catalyst may be applied to degrade organic pollutants efficiently.