A General Synthetic Route to Atomically Dispersed Catalysts for Revealing Their Catalytic Trends in Oxygen Reduction Reaction

Abstract

MAT.P-356 A General Synthetic Route to Atomically Dispersed Catalysts for Revealing Their Catalytic Trends in Oxygen Reduction Reaction

Jae Hyung Kim, Hyungjun Kim1, Sang Hoon Joo2,*

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Korea

1 Korea Advanced Institute of Science and Technology, Korea

2 Division of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Korea

Area: Material Chemistry Type: Poster Presentation Code: MAT.P-356 Location: Exhibition Hall 1 Date: THU 11:00~12:30

Atomically dispersed catalysts have recently emerged as a research frontier in catalysis with their maximum atom efficiency and unusual catalytic reactivity. However, a generic strategy toward atomically dispersed catalysts of wide range of compositions is still lacking, which has often limited systematic studies that can unravel the catalytic origins of atomically dispersed catalysts. In the work, we present a generalized synthetic route to atomically dispersed catalysts of precious metals, which consists of “trapping” of precious metal precursors and “stabilizing” them with SiO2 layers. Through mass spectrometry analyses during activation processes of catalysts, we demonstrated that the “trapping-and-stabilizing” method is capable of impeding the decomposition of a metal precursor, preserving atomically dispersed sites. Five atomically dispersed precious metals (Os, Ru, Rh, Ir, and Pt) catalysts were obtained and served as model catalysts for unravelling reactivity trends of atomically dispersed catalysts for oxygen reduction reaction (ORR). Combining experimental results and density functional theory calculations, we revealed that higher H2O2 selectivity was shown in atomically dispersed catalysts compared to their nanoparticle counterparts, which originates from abnormally weakened oxygen binding energies and isolated geometric configurations of atomically dispersed sites. Furthermore, the relative binding energies of *OOH and *O species were identified as determinants that dictate the ORR selectivity of atomically dispersed catalysts. This rational approach for preparing atomically dispersed catalysts can aid in enhancing the understanding their universal catalytic behaviors for ORR.