TY - JOUR A1 - Heenemann, Maria A1 - Millet, Marie-Mathilde A1 - Girgsdies, Frank A1 - Eichelbaum, Maik A1 - Risse, Thomas A1 - Schlögl, Robert A1 - Jones, Travis A1 - Frei, Elias T1 - The Mechanism of Interfacial CO2 Activation on Al Doped Cu/ZnO JF - ACS Catalysis N2 - We report on a combined quantitative charge carrier and catalytic activity analysis of Cu/ZnO(:Al) model catalysts. The promoting effect of Al3+ on the ZnO support for CO2 activation via the reverse water–gas-shift reaction has been investigated. The contact-free and operando microwave Hall Effect technique is applied to measure charge carriers in Cu/ZnO(:Al) based model catalysts under reverse water–gas shift reaction conditions. This method allows us to monitor the electrical conductivity, charge carrier mobility, and absolute number of charge carriers. An increase in charge carrier concentration with increasing Al3+ content and its direct correlation with the catalytic activity for CO formation is found. We conclude that the increased availability of charge carriers plays a key role in CO2 activation and CO formation, which finds additional support in a concurrent decrease of the apparent activation energy and increase in the reaction order of CO2. In combination with comprehensive DFT calculations, the impact of the interfacial charge transfer, coupled to oxygen defect sites in ZnO and CO2 adsorption properties, is elucidated and highlighted. In conclusion, the results from this operando investigation combined with DFT calculations demonstrate the importance of charge transfer processes as decisive descriptors for understanding and explaining catalytic properties. KW - CO2 activation Al doped Cu/ZnO charge carrier quantification Cu−ZnO interface rWGS activity Y1 - 2020 U6 - https://doi.org/10.1021/acscatal.0c00574 SN - 2155-5435 VL - 10 IS - 10 SP - 5672 EP - 5680 PB - American Chemical Society (ACS) ER -