Influence of interlayer water molecules in Ni-based catalysts for oxygen evolution reaction

Nickel-iron layered double hydroxides (NiFe LDHs) have been identified as one of the best promising electrocatalysts-candidates for oxygen evolution reaction (OER). However, the catalytic activity effected by interlayer water molecules is ignored and rarely reported. Herein, Ni(OH)2, NiFe LDHs vertically aligned Ni foam are designed for OER. As a contrast, the corresponding electrocatalysts with the removal of the interlayer water molecules (Ni(OH)2-AT, NiFe LDHs-AT) are developed to probe into the influence of the interlayer water molecules towards OER. As expected, NiFe LDH nanoplates exhibit excellent catalytic performance and durability for water electrolysis in alkaline conditions with lower overpotential and smaller Tafel slope compared to those of NiFe LDHs-AT, which are influenced mainly by stability of crystal structure due to the existence of interlayer water molecules. The discovery opens up a similar pathway by controlling the amount of water molecules to boost catalytic performance for studying other electrocatalysts with heteroatom dopant.