Revista de Química e Engenharia Química Aplicada

Super-wetting micro-/nanostructured electrodes for gasinvolved electro-catalysis

Xiaoming Sun

Electrochemical gas-involved reactions can be divided into two types: gas-evolution reaction and gas-consumption reaction, both of which are crucial for a variety of energy conversion processes and industries (e.g. HER and ORR). For gas-evolution reaction, if generated gas bubbles pin at the electrode surface and cannot escape from the surface in time, the accumulated bubbles will reduce the effective electrode surface area, increase diffusion resistance and enlarge polarization effect, resulting in more energy consumption. How to construct a novel electrode to promote gas bubble release is critical for improving the electrochemical efficiency besides activity improvement. Inspired from bio-inspired superwetting surfaces, we found that the interface behavior of electrode could be tuned by surface architecture construction, for example, transferring from aerophobic to superaerophobic by engineering a series of micro-/nanostructured electrode, e. g. MoS2, pine-shaped Pt, NiFe LDHs and Cu films. This kind of superaerophobic electrodes could decrease the critical size of gas overflowing from the surface by cutting the three phase contact lines into discontinue dots, and thus reduce the diffused impedance and maintain the integrity of the solid?liquid interface that is necessary for electrocatalysis (e.g. water splitting and hydrazine fuel cells). On the other hand, for gas-consumption reaction, the construction of micro-/nanostructured