Journal:Nat. Energy

Abstract:Development of low-cost and high-performance oxygen evolution reaction catalysts is key to implementing polymer electrolyte membrane water electrolysers for hydrogen production. Iridium-based oxides are the state-of-the-art acidic oxygen evolution reaction catalysts but still suffer from inadequate activity and stability, and iridium's scarcity motivates the discovery of catalysts with lower iridium loadings. Here we report a mass-selected iridium–tantalum oxide catalyst prepared by a magnetron-based cluster source with considerably reduced noble-metal loadings beyond a commercial IrO2 catalyst. A sensitive electrochemistry/mass-spectrometry instrument coupled with isotope labelling was employed to investigate the oxygen production rate under dynamic operating conditions to account for the occurrence of side reactions and quantify the number of surface active sites. Iridium–tantalum oxide nanoparticles smaller than 2 nm exhibit a mass activity of 1.2 ± 0.5 kA gIr–1 and a turnover frequency of 2.3 ± 0.9 s−1 at 320 mV overpotential, which are two and four times higher than those of mass-selected IrO2, respectively. Density functional theory calculations reveal that special iridium coordinations and the lowered aqueous decomposition free energy might be responsible for the enhanced performance.

Note:Ya-Rong Zheng†, Jerome Vernieres†, Zhenbin Wang†, Ke Zhang†, Degenhart Hochfilzer, Kevin Krempl , Ting-Wei Liao, Francesco Presel  , Thomas Altantzis, Jarmo Fatermans, Soren Bertelsen Scott, Niklas Mørch Secher, Choongman Moon, Pei Liu, Sara Bals, Sandra Van Aert   , Ang Cao, Megha Anand, Jens K. Nørskov*, Jakob Kibsgaard, and Ib Chorkendorff*

Volume:7

Page Number:55-64

Translation or Not:no

Date of Publication:2022-01-01

Links to published journals:https://www.nature.com/articles/s41560-021-00948-w