Selective Catalyst Surface Access through Atomic Layer Deposition

Abstract

Catalyst poisoning is a prominent issue, reducing the lifetime of catalysts and increasing the costs of the processes that rely on them. The electrocatalysts that enable green energy conversion and storage, such as proton exchange membrane fuel cells and hydrogen bromine redox flow batteries, also suffer from this issue, hindering their utilization. Current solutions to protect electrocatalysts from harmful species fall short of effective selectivity without inhibiting the required reactions. This article describes the protection of a standard 50% Pt/C catalyst with a V2O5 coating through atomic layer deposition (ALD). The ALD selectively deposited V2O5 on the Pt, which enhanced hydrogen transport to the Pt surface and resulted in a higher mass activity in alkaline electrolytes. Cyclic voltammetry and X-ray photoelectron spectroscopy showed that the Pt was protected by the coating in the HBr/Br2 electrolyte which dissolved the uncoated 50% Pt/C in under 3 min.

Precise control of the catalyst interface at the atomic level

“…ALD can be used to build a uniform transition metal-based oxide coating on complex substrates, thus avoiding catalyst poisoning and catalyst deactivation. 101 For example, Zitoun et al 102 studied application of a metal oxide to a standard Pt/C catalyst by ALD (720 cycles) (Fig. 4d).…”

“…(d) HRTEM image of Pt/C with 720 ALD cycles. (e) Poisoning test for as-prepared catalysts 102. Copyright 2021, American Chemical Society.…”