Design Principles and Mechanistic Understanding of Cobalt‐Oxide‐Based Electrocatalysts for Nitrate Reduction to Ammonia

ABSTRACT The concern about nitrates in groundwater has led to an environmental problem due to their adverse impacts on both humans and ecosystems. Hence, treating nitrate‐based wastewater is significant and challenging for biological denitrification processes. Electrocatalytic nitrate reduction reaction (EC‐)‐to‐ammonia (NH 3 ) conversion surfaces are promising avenues for reducing nitrate from wastewaters, simultaneously producing ammonia. Co 3 O 4 ‐based materials exhibit significant advantages in promoting selective , characterized by efficient conversion efficiency, high ammonia selectivity, and high Faradaic efficiency (FE). In this review, we broadly address the recent trends and advances in ‐to‐NH 3 formation using Co 3 O 4 and XCo 2 O 4 ‐based spinel materials. Various kinds of Co 3 O 4 and Co 3 O 4 ‐metal oxide composite‐based materials, including monometallic, bimetallic, and Co 3 O 4 ‐based inorganic‐organic hybrid materials and their derivatives, are discussed, highlighting the role of their structural and compositional attributes in promoting NO 3 ‐to‐NH 3 conversion and a detailed study of the Zn‐ battery mechanism. Finally, future directions, challenges, and opportunities are briefly discussed in the field related to Co 3 O 4 ‐based EC‐.