Tailoring liquid/solid interfacial energy transfer: Fabrication and application of multiscale metallic surfaces with engineered heat transfer and electrolysis properties via femtosecond laser surface processing techniques

Femtosecond Laser Surface Processing (FLSP) is a powerful technique for the fabrication of self-organized multiscale surface structures on metals that are critical for advanced control over energy transfer at a liquid/solid interface in applications such as electrolysis. The efficiency of the hydrogen evolution reaction on stainless steel 316 electrodes in a 1 molar potassium hydroxide solution is used to analyze the role of surface geometry to facilitate the phase conversion of the liquid to a gaseous state in the vicinity of the interface. It is found that the efficiency of the electrolysis process is directly related to the separation of micro-scale features on an electrode surface. The enhancement is attributed to the size of the valleys between microstructures controlling the contact between an evolving vapor bubble and the electrode surface. The results suggest an alternative pathway for the tailoring of interfacial energy transfer on structured surfaces separate from traditional benchmarks such as surface area and contact angle.