Designing Atomically Dispersed Electrocatalysts for Controlling Catalytic Selectivity

Abstract

The control of catalytic selectivity plays a pivotal role in electrocatalytic reactions to produce desired products. In this presentation, we present the design of electrocatalysts comprising atomically dispersed active sites, which enable selective oxygen reduction reaction (ORR) and chlorine evolution reaction (CER). We developed a general synthetic strategy that can produce atomically dispersed precious metal catalysts (Os, Ru, Rh, Ir, and Pt), which served as model catalysts for unraveling catalytic trends for the ORR. The atomically dispersed precious metal catalysts showed higher selectivity for H2O2 production than their NP counterparts for the ORR owing to their isolated geometry. Among the atomically dispersed catalysts, the H2O2 selectivity was changed by the types of metals, with atomically dispersed Pt catalyst showing the highest selectivity. The selectivity trend of atomically dispersed catalysts could be correlated to the binding energy difference between *OOH and *O species. For the selective CER, we found that atomically dispersed Pt−N4 sites doped on a carbon nanotube (Pt1/CNT) can catalyze the CER with excellent activity and selectivity. The Pt1/CNT catalyst showed superior CER activity to a Pt nanoparticle-based catalyst and a commercial Ru/Ir-based metal oxide catalyst. Notably, Pt1/CNT exhibited near 100% CER selectivity in acidic media with low Cl– concentrations (0.1 M) as well as in neutral media, whereas the MMO catalyst showed substantially lower CER selectivity.