Engineering stable Pt nanoclusters on defective two-dimensional TiO2 nanosheets by introducing SMSI for efficient ambient formaldehyde oxidation

The strong metal-support interaction (SMSI) has received wide attention in heterogeneous catalysis for the room-temperature oxidation of formaldehyde. An interaction between Pt nanoclusters and oxygen vacancy defects will lead to SMSI over the Pt-based catalysts. In this study, defective two-dimensional (2D) TiO2 nanosheets were synthesized and successfully anchored Pt nanoclusters with a size of 1.3 nm (0.1Pt/TiO2-NS). The 0.1Pt/TiO2-NS catalyst displayed a superior activity of > 95% HCHO conversion at room temperature, which was ∼ 50% higher than that obtained for a counterpart having the commercial TiO2 (Degussa P25) support. The abundant oxygen vacancies and stable Pt nanoclusters on 0.1Pt/TiO2-NS by introducing SMSI boosted the excellent activity and stability of HCHO oxidation. By exploring electron transfer, suppression of small-molecule adsorption and encapsulation, SMSI was well demonstrated. Furthermore, electron transfer from Pt to TiO2-NS led to the electron-deficient Pt surface. The electron-deficient Pt caused by SMSI will enhance the adsorptions of HCHO and H2O/O2, subsequently improving the catalytic performance. SMSI between Pt nanoclusters and oxygen vacancies endowed the 0.1Pt/TiO2-NS catalyst excellent activity and stability to HCHO elimination. In addition, the mechanism for the high HCHO oxidation performance were examined through analysis of in situ HCHO-diffuse reflectance infrared Fourier transform spectra (DRIFTS).