Chinese scholars have made progress in the mechanism of electrocatalytic double layer

Fig.
The surface interface structure of hydrogen electrocatalytic system in acid and alkali media and its correlation with reaction kinetics

With the support of the National Natural Science Foundation of China (grant number: 21832004, 21673163), Professor Chen Shengli's team at Wuhan University has made progress
in the mechanism of electrocatalytic double layer 。 The research results, entitled "Hydrogen bond network connectivity in the electric double layer dominates the kinetic pH effect in hydrogen electrocatalysis on Pt", were published on September 29, 2022 in Nature
Catalysis.
Links to papers: _istranslated="1">.

In the field of electrocatalysis, the significant slowdown of hydrogen electrode reaction kinetics under alkaline conditions is a long-term unsolved problem
.
So far, the kinetic pH effect study mainly considers the effect of the adsorption of *H and *OH on the energy of the surface reaction step, and ignores the dependence
of the interface electric double layer structure on pH.
Accurately obtaining the microstructure characteristics of the electric double layer at the interface of hydrogen electrocatalytic systems under different pH conditions will be a breakthrough point
to solve this problem.
However, it is still a huge challenge
to analyze the interface structure and process of electrocatalytic systems at the atomic and molecular scales.

Professor Shengli Chen's team combined ab initio molecular dynamics (AIMD) simulation, computational vibrational spectroscopy of interfacial water molecules, and in situ surface enhanced infrared spectroscopy (in situSEIRAS) to find that hydrogen bond network connectivity in the interfacial electric double layer is the root cause of the huge kinetic pH effect of hydrogen electrocatalysis (Fig.
).

Subsequently, using Pt-Ru alloy as a model catalyst, the essence of OHAD_adsorption intermediates in improving the kinetics of basic hydrogen electrocatalytic reactions was further revealed, that is, increasing the connectivity of hydrogen bond networks in the electric double layer
.

This study combines AIMD simulation, computational spectroscopy and experimental spectroscopy techniques to provide research ideas
for the atomic structure of electrochemical interfaces.