On the importance of the electric double layer structure in aqueous electrocatalysis

To design electrochemical interfaces for efficient electric-chemical energy interconversion, it is critical to reveal the electric double layer (EDL) structure and relate it with electrochemical activity; nonetheless, this has been a long-standing challenge. Of particular, no molecular-level theories have fully explained the characteristic two peaks arising in the potential-dependence of the EDL capacitance, which is sensitively dependent on the EDL structure. We herein demonstrate that our first-principles-based molecular simulation reproduces the experimental capacitance peaks. The origin of two peaks emerging at anodic and cathodic potentials is unveiled to be an electrosorption of ions and a structural phase transition, respectively. We further find a cation complexation gradually modifies the EDL structure and the field strength, which linearly scales the carbon dioxide reduction activity. This study deciphers the complex structural response of the EDL and highlights its catalytic importance, which bridges the mechanistic gap between the EDL structure and electrocatalysis.

In situ/operando investigation of catalytic and electrocatalytic interfaces

In situ and operando spectroscopic methods play a fundamental role in a variety of different fields of modern science. In particular, as energy and environmental science have become increasingly important recently, the need of in situ and operando spectroscopic methods has also increased significantly. Therefore, we felt it was time to have a special issue focused on such techniques and for which the aim is ‘to merge the research communities investigating catalytic and (photo)electrochemical interfaces with different in situ/operando spectroscopic techniques, to share recent results, experimental methods, and future perspectives’, as we reported in the scope of this special issue. With its 23 original research papers and 2 topical reviews, spanning from heterogeneous catalysis to photoelectrochemistry, we believe that the outcome of this special issue fulfills the aforementioned aim.