posted on 2022-01-27, 21:31authored byAidan
Q. Fenwick, Alex J. Welch, Xueqian Li, Ian Sullivan, Joseph S. DuChene, Chengxiang Xiang, Harry A. Atwater
We report the use of a nanoporous
gold (np-Au) catalyst for CO2 reduction in a gas diffusion
electrode (GDE) and characterize
the role of wetting in electrochemical performance. The np-Au catalyst
has pores on the order of 20 nm and is cross-sectionally isotropic,
enabling Faradaic efficiencies for CO of greater than 95% across a
wide range of potentials and a maximum partial current density for
CO of 168 mA/cm2. Secondary ion mass spectroscopy and in situ copper underpotential deposition were employed to
provide insights into catalyst wetting. At a typical CO2 flow rate of 50 SCCM, approximately half of the catalyst is in contact
with the electrolyte during operation, and the dry region exists in
the bottom half of the nanoporous catalyst. We discuss implications
of the nanoporous GDE wetting characteristics for catalyst performance
and the design of improved GDE architectures that can maximize the
catalytically active area.