催 化 论 坛
Operando Studies of Working Catalysts: Surface Spectroscopy and Microscopy
Prof. Günther Rupprechter
Technische Universitat Wien, Austria
The main focus of my group is to study catalytic surface reactions on heterogeneous catalysts via a three-fold approach, employing surface science based planar model catalysts, atomically-precise clusters, and technological industrial-grade catalysts. This strategy has been applied to elucidate molecular mechanisms of some environmentally relevant catalytic reactions: hydrogen as clean fuel, more efficient automotive catalysis, and waste remediation. Core materials studied were mono- (Pt, Pd, Ni, Au, Co) and bimetallic (PdZn, Pd2Ga, PdCu, CuNi) nanoparticles on various supporting (mixed) oxides (Al2O3, CeO2, ZrO2, Ga2O3, Co3O4).
A central theme is to examine active functioning catalysts under operating conditions, at near atmospheric pressure (NAP) and elevated temperature, applying operando surface spectroscopy, such as Fourier transform infrared spectroscopy (FTIR), X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (NAP-XPS), and X-ray diffraction (XRD). For model catalysts, analogous operando studies are performed by sum frequency generation (SFG) laser spectroscopy, polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) and NAP-XPS. To image surface reactions by in situ surface microscopy, photoemission electron microscopy (PEEM) is applied to polycrystalline and powder samples. Most operando studies are performed at synchrotron sources and in lock-step with theory.
The presentation will give a short insight into most recent operando studies: spectroscopy on commercial Co3O4 and perovskite surfaces, as well as microscopy on model Pd/ZrO2.
Günther Rupprechter received his Ph.D. in Physical Chemistry in 1996 from the University Innsbruck, Austria. After being a postdoctoral fellow at the University of California at Berkeley, he was group leader for Laser Spectroscopy and Catalysis at the Fritz Haber Institute of the Max Planck Society in Berlin (Germany) from 1999 to 2005. In 2005 he accepted a Full Professorship in Surface and Interface Chemistry at Technische Universitat Wien. He is the Vice-Chair of the Austrian Catalysis Society, Speaker of the FWF Special Research Program (SFB) "Functional Oxide Surfaces and Interfaces (FOXSI)", as well as Editorial Board Member of "Catalysis Letters" and "Topics in Catalysis". His research emphasis is on heterogeneous catalysis, particularly in situ (operando) spectroscopy/microscopy on model and technological catalysts. In 2005 he received the Jochen Block Award of the German Catalysis Society for "the application of surface science methods to heterogeneous catalysis" and became corresponding member of the Austrian Academy of Sciences in 2012.