A superaerophilic gas diffusion electrode enabling facilitated nitrogen feeding through hierarchical micro/nano channels for efficient ambient synthesis of ammonia

Abstract

Electroreduction of nitrogen brings new opportunities for synthetic ammonia industry to meet the ever-growing needs of carbon neutrality. While efforts are focused on optimizing catalyst activity, facilitating efficient nitrogen-catalyst contact within working electrode to maximize three-phase reaction region remains a significant challenge, leaving the utilization rate of electrocatalyst much to be desired. Here, we design a superaerophilic electrode with hierarchical gas diffusion channels to address this problem. Upon getting access to electrode surface, the supplied N2 bubbles are shattered into nanoscale ones with the aid of nanocomponents, followed by smooth transfer towards inner electrocatalyst through the broad channels constructed by microcomponents. This strategy affords ultra-high three-phase reaction region inside the working electrode and enables fully function of the electrocatalyst. The application of such superaerophilic gas diffusion electrode generates a nearly 6-fold increase in Faradaic efficiency (85.9 %) compared with the conventional electrode, much approaching the target set by the U.S. Department of Energy (90 %).