Title: Revealing the Role of Interfacial Properties on Catalytic Behaviors by in Situ Surface-Enhanced Raman Spectroscopy

Author: Hua Zhang, Xia-Guang Zhang†, Jie Wei, Chen Wang, Shu Chen‡, Han-Lei Sun, Ya-Hao Wang, Bing-Hui Chen* , Zhi-Lin Yang, De-Yin Wu, Jian-Feng Li* , and Zhong-Qun Tian  

Abstract:

Insightful understanding of how interfacial structures and properties affect catalytic processes is one of the most challenging issues in heterogeneous catalysis. Here, the essential roles of Pt–Au and Pt−oxide−Au interfaces on the activation of H₂ and the hydrogenation of para-nitrothiophenol (pNTP) were studied at molecular level by in situ surface-enhanced Raman spectroscopy (SERS) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). Pt–Au and Pt–oxide–Au interfaces were fabricated through the synthesis of Pt-on-Au and Pt-on-SHINs nanocomposites. Direct spectroscopic evidence demonstrates that the atomic hydrogen species generated on the Pt nanocatalysts can spill over from Pt to Au via the Pt–Au and Pt–TiO₂–Au interfaces, but would be blocked at the Pt–SiO₂–Au interfaces, leading to the different reaction pathways and product selectivity on Pt-on-Au and Pt-on-SHINs nanocomposites. Such findings have also been verified by the density functional theory calculation. In addition, it is found that nanocatalysts assembled on pinhole-free shell-isolated nanoparticles (Pt-on-pinhole-free-SHINs) can override the influence of the Au core on the reaction and can be applied as promising platforms for the in situ study of heterogeneous catalysis. This work offers a concrete example of how SERS/SHINERS elucidate details about in situ reaction and helps to dig out the fundamental role of interfaces in catalysis.

                          



Full Link: http://pubs.acs.org/doi/10.1021/jacs.7b04011