Hydrophobic electrocatalyst for the enhanced activity of oxygen reduction reaction through controllable liquid/gas/solid interface

Abstract

Slow gas consumption process has been considered as one of the main limiting factors to enhance the activity of oxygen reduction reaction (ORR). The superwettable materials can overcome the limitation of underliquid gas transport in electrocatalysis, however, most of the preparation process are complex and high cost. Herein, an electrocatalyst for ORR is synthesized by loading ZIF-67 on carbon black, then the hydrophobicity is bestowed on the catalyst and controlled by adjusting the amount of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, aimed to preparing the carbon-based electrocatalyst with hydrophobic surface (Cal-CoZIF-XE2B/PFDS). Continuous and abundant cavitations on the catalyst surface ensure the rapid diffusion of oxygen to the three phase contact area of the reaction system. Compared with the unmodified catalyst, the hydrophobic catalyst has larger diffusion-limited current density (from 4.4 mA/cm2 of the original catalyst to 5.2 mA/cm2 of the modified catalyst) and higher half-wave potential (from 0.81 V of the original catalyst to 0.83 V of the modified catalyst). Furthermore, the as-prepared electrocatalysts which obtained with low cost and simple method, presenting durability and stability against alkaline and acidic electrolyte solutions and providing a general and reliable strategy for the study of ORR catalyst.