nz9b01527_si_002.cif (25.43 kB)
In Situ Modification of a Delafossite-Type PdCoO2 Bulk Single Crystal for Reversible Hydrogen Sorption and Fast Hydrogen Evolution
dataset
posted on 2019-08-20, 18:56 authored by Guowei Li, Seunghyun Khim, Celesta S. Chang, Chenguang Fu, Nabhanila Nandi, Fan Li, Qun Yang, Graeme R. Blake, Stuart Parkin, Gudrun Auffermann, Yan Sun, David A. Muller, Andrew P. Mackenzie, Claudia FelserThe
observation of extraordinarily high conductivity in delafossite-type
PdCoO2 is of great current interest, and there is some
evidence that electrons behave like a fluid when flowing in bulk crystals
of PdCoO2. Thus, this material is an ideal platform for
the study of the electron transfer processes in heterogeneous reactions.
Here, we report the use of bulk single-crystal PdCoO2 as
a promising electrocatalyst for hydrogen evolution reactions (HERs).
An overpotential of only 31 mV results in a current density of 10
mA cm–2, accompanied by high long-term stability.
We have precisely determined that the crystal surface structure is
modified after electrochemical activation with the formation of strained
Pd nanoclusters in the surface layer. These nanoclusters exhibit reversible
hydrogen sorption and desorption, creating more active sites for hydrogen
access. The bulk PdCoO2 single crystal with ultrahigh conductivity,
which acts as a natural substrate for the Pd nanoclusters, provides
a high-speed channel for electron transfer.