Crystal Phase Mediated Restructuring of Pt on TiO2 with Tunable Re-activity: Redispersion versus Reshaping

Xiaoben Zhang; Zhimin Li; Wei Pei; Gao Li; Wei Liu; Pengfei Du; Zhen Wang; Zhaoxian Qin; Si Zhou; Jijun Zhao; Bing Yang; Wenjie Shen

doi:10.26434/chemrxiv-2021-cq50f

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Crystal Phase Mediated Restructuring of Pt on TiO2 with Tunable Re-activity: Redispersion versus Reshaping

Working Paper

Xiaoben Zhang Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Zhimin Li State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Wei Pei Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China. ,
Gao Li State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Wei Liu Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Pengfei Du Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Zhen Wang Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Zhaoxian Qin State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Si Zhou Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China. ,
Jijun Zhao Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian, 116024, China. ,
Bing Yang Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China. ,
Wenjie Shen State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.

Abstract

Restructuring of supported metal nanoparticles (NPs) e.g., reshaping and redispersion are of tremendous interest for the rational design of high-efficiency catalyst materials with precise particle sizes, shapes, and reactivities. Here we show a crystal phase mediated restructuring of Pt NPs on TiO2, as a simple approach for fabricating either atomically dispersed single atoms (SAs) or reshaped planar NPs of Pt catalysts with tunable reactivities. Utilizing a variety of state-of-the-art characterizations, we showed that rutile TiO2 favors the reshaping of 2D planar Pt NPs, whereas the anatase surface facilitates the redispersion of Pt NPs to SAs upon calcination in the air up to 400 ºC. Environmental transmission electron microscopy (ETEM) and density function theory (DFT) calculations were employed to directly visualize the dynamic transformation of Pt NPs and reveal the specific role that TiO2 supports play in promoting the stability and diffusion of Pt SAs. As a result, the reverse reactivity was achieved by tunning their distinct restructuring behaviors. Thus, the Pt SAs on anatase TiO2 preferentially activated selective hydrogenation of phenylacetylene (21.22 x 10-2 s-1 at 50 ºC), while planar Pt NPs on rutile significantly enhanced the combustion of methane (3.11 x 10-2 s-1 at 310 ºC). Our results therefore open up new routes for tuning the restructuring behavior of supported metal catalysts and designing catalysts with controlled catalytic structures and reactivities.