Identifying active catalyst sites

Heterogeneous catalysts are crucial in the chemical and energy industries. Their activity is determined by specific sites that control the conversion of reactant molecules into product molecules. But the direct identification and monitoring of these sites during reactions is challenging. Jonas Pfisterer et al. now show that this is readily achieved using widely available scanning tunnelling microscopes by monitoring changes in the noise level during measurement. The data they collect enables the authors to distinguish between active sites, such as different defect sites and sites at the boundary between different materials comprising the catalyst, in an almost quantitative fashion. This information makes it possible to directly evaluate the importance and relative contribution of different sites to overall catalyst activity, which can directly feed into the rational design and optimization of heterogeneous catalysts targeted for a wide range of practical applications.