报告题目：In situ investigation of chemical reactions on metal-oxide model nanocatalysts: near-ambient pressure XPS and STM studies
报告人：Professor Ahmed and Professor Richard （法国索邦大学）
主持人：徐亚东 教授
报告时间：2019年5月7日8:30
报告地点：公字楼334会议室
报告人简介：
Dr Ahmed NAÏTABDI is associate professor in Sorbonne University since 2012 and Deputy-director of Laboratory of Chemical Physics Mater and Radiation (director Dr Richard TAÏEB). His research interests focus on the investigation of chemical reactions with advanced spectroscopic tools for nanocatalysis applications in particular relevant for new energy solutions. He earned his thesis in the University of Strasbourg in 2004 where he investigated the properties of high spin molecular magnets. Afterwards he joined the University of Central Florida in Orlando (USA) for as a postdoctoral research fellow from 2005 to 2008 where he studied the properties of size-selected bimetallic nanoparticles for heterogeneous catalysis applications. |
Richard Taieb. 1987: Student at the Ecole Normale Supérieure; 1992: PhD at the Laboratory de Chimie Physique Matière et Rayonnement (LCPMR); 1992-3: Postdoc at JILA, Boulder Colorado USA; 1993: Researcher of CNRS at LCPMR; 2011 Director of Research; 2019: Head of the LCPMR
Theoretician of atoms/molecules in strong short laser fields. Attoscience. Ultra fast phenomena.
报告摘要：
The increase of public awareness and concerns about emissions from fossil fuel combustions offer great opportunities to seek for new energy sources with minimal impact on the environment and human health, in particular in the urging need for alternative mobility solutions. Fuel cells are among the best candidates in this regard owing to their distinctive advantages. However, several hindrances have to be lifted before reaching a widespread commercial utilization. In particular, significant improvements are needed on the performances of the nanocatalysts (NCs). |
Our project provides the opportunity to design new efficient and cost effective metal-oxide NCs by investigating their proprieties with innovative in situ spectroscopic techniques, such as near-ambient pressure XPS (NAP-XPS). Here, we focus on Pt-based NCs which are the most prominent catalysts owing to their particular high catalytic activity. Their applications in automotive industry, particularly as remarkable catalysts for the reduction of CO emissions, and in the hydrogen gas purification for fuel cells utilization, are among the most peculiar use of Pt. We provide a comprehensive and comparative study on Pt, Zn, ZnOPt NCs and their corresponding Pt(111) and ZnO/Pt(111) model nanocatalysts. From STM investigations, well-ordered nanostructures show significant electronic properties change as a function of the thickness from sub-monolayer up to 4 ML thick ZnO film). Core-level spectra of C 1s, O1s, Pt 4f acquired by NAP-XPS in real-time and in isobar conditions (at 1 mbar) show the onset of the CO oxidation reaction. NAP-XPS provides a “synoptic view” of both the catalytic surface and the gas phase in the immediate vicinity of the surface. The role of adsorbed species (hydroxyls) and intermediates such formates, carbonates and hydroxyls was unveiled in the CO oxidation reaction. Finally, the issue of mass transport limitation (MTL), associated with a CO2-rich boundary layer in the vicinity of the surface in the study state regime was studied carefully.
