Ultrahigh Hydrogen Evolution Performance of Under-Water 'Superaerophobic' MoS_2 Nanostructured Electrodes

摘要

Electro-catalytic gas evolution reactions, where molecular gasses are generated by electrochemical reduction or oxidation, hold keys to a number of important energy conversion and storage processes. These reactions need catalysts and many excellent catalysts are demonstrated recently. However, even for terrific catalysts, the adhesion of as-formed gas bubbles on traditional flat electrode surface is still a big issue (Figure 1A, left), which blocks the electrolyte diffusion, creates dead area (the brown zone, and the brown line in inset), causes more ohmic drop, and results in an impeded mass transfer process and compromised performance. Although the disengagement process of gas bubbles can be prompted in certain degree by inducing ultragravity or ultrasonic treatment, they are not cost-effective for industrial production where a high current density (hundreds of mA • cm~(-2)) are required at a static working condition. Thus, how to drive off the as-formed gas bubbles from the electrodes in a simple way remains a challenge. Recent successes in tuning the adhesion behavior ("superaerophilic bursting state", and high adhesion "superaerophobic pinning state") and achieving low adhesion underwater "superoleo-phobic" surfaces by constructing microano structures provide inspiration for addressing the bubble adhesion issue on electrodes.