Construction of hierarchical bundle-like CoNi layered double hydroxides for the efficient oxygen evolution reaction

Abstract Electrochemical water splitting is a promising approach for the production of H 2 fuel while greatly limited by the sluggish anodic oxygen evolution reaction (OER). In this regard, searching for a highly efficient and durable OER catalyst with low cost, abundant active sites, and excellent durability is increasingly demanded. Herein, a facile one-pot hydrothermal method that using urea as pH regulator is demonstrated to engineer nanobundle-like CoNi layered double hydroxides (CoNi LDHs) with high surface areas and rich oxygen vacancies. As a result, by virtue of the nanobundle-like structure, abundant oxygen vacancies, as well as the modified electronic structures, the optimized Co 1 Ni 0.3 LDHs can deliver the current density of 10 mA/cm 2 with the overpotentials of only 266 mV, much superior than those of Ir/C, Co(OH) 2 , and Ni(OH) 2 catalysts. More importantly, the resultant Co 1 Ni 0.3 LDHs also possesses excellent stability catalytic activity without negligible activity decay for at least 22 h. Our work not only establishes a potential OER electrocatalyst, but also open up a new avenue for the design and development of highly active electrocatalysts with controlled shapes.