Pt-Based Single Atom Electrocatalysts By Atomic Layer Deposition for Fuel Cell Related Catalytic Reactions

Abstract

Platinum is a key component of the catalysts in a proton-exchange membrane fuel cell (PEMFC), which exhibited good oxygen reduction reaction (ORR) activity. Notwithstanding the superior properties of Pt catalysts, the low abundance of Pt, and subsequent high cost have created a major barrier for the large-scale commercialization of Pt catalysts in PEMFCs. One effective route for reducing the cost of Pt is to increase the atom utilization efficiency by reducing the particle size to clusters or even single atoms catalysts.[1] Herein, we will demonstrate our recent approaches about the preparation of Pt-based single atom catalysts by atomic layer deposition method (ALD). Nearly 100% Pt single atom catalysts were successfully deposited on N-doped carbon nanotubes. Pt-Pd single atom alloys were prepared through ALD method and applied in electrochemical oxygen reduction for the first time. We also successfully prepared successfully prepared Pt-Ru dimers on NCNTs through ALD process. All these different types of single atom catalysts exhibited superior activity in ORR and HER reactions. In conclusion, we demonstrate a series types of Pt single atoms, including high-quality Pt single atom, Pt-Pd single atom alloy and Pt-Ru dimer structures. The results show that the formation of single atom structure can effectively improve the electrochemical performance. It is also worth to mention that we have first introduced ALD technique in the single atoms. It is believed that our study opens up a new avenue of developing new types of Pt-based catalysts for fuel cells and brings new understanding about catalytic performances of single atoms.[1] L. Zhang, X. Sun et al, Pt-Based Electrocatalysts with High Atom Utilization Efficiency: From Nanostructures to Single Atoms Energy Environ. Sci. 2019, 12, 492-517.[2] L. Zhang, X. Sun et al, Atomic Layer Deposited Pt-Ru Dual-Metal Dimers and Identifying the Active Sites of Dimer for High Hydrogen Evolution Reaction. Nature Commun. 2019, 10, 4936.[3] L. Zhang, X. Sun et al, Pt/Pd Single Atom Alloys as Highly Active Electrochemical Catalysts and the Origin of Excellent Activity. ACS Catalysis, 2019, 9, 9350.[4] L. Zhang, X. Sun et al, New Insight of Pyrrole-Like Nitrogen for Boosting Hydrogen Evolution Activity and Stability of Pt Single Atoms. Small 2020, in press.