Iron-Doped Nickel Hydroxide Nanosheets as Efficient Electrocatalysts in Electrochemical Water Splitting

Abstract

The development of non-noble-metal-based electrocatalysts for water electrolysis is essential to produce sustainable green hydrogen. Highly active and stable non-noble-metal-based electrocatalysts are greatly needed for the replacement of the benchmark electrocatalysts of iridium, ruthenium, and platinum oxides. Herein, we synthesized non-noble-metal-based, Fe-doped, β-Ni(OH)2 interconnected hierarchical nanosheets on nickel foam via a conventional hydrothermal reaction. Iron doping significantly modified the electronic structure of β-Ni(OH)2 due to the electron transfer of iron to nickel hydroxide. Fe-doped β-Ni(OH)2 was investigated both as a cathode and anode electrode for hydrogen and oxygen evolution reactions (OERs and HERs). It facilitated significant improvements in electrochemical performance due to its huge intrinsic active sites and high electrical conductivity. As a result, the electrocatalytic activity of Fe-doped Ni(OH)2 exhibited a lesser overpotential of 189 and 112 mV at a current density of 10 mA cm−2 and a Tafel slope of 85 and 89 mV dec−1 for the OER and HER, respectively. The Fe-doped β-Ni(OH)2 displayed excellent durability for 48 h and a cell voltage of 1.61 V @ 10 mA cm−2. This work demonstrates that Fe-doped β-Ni(OH)2 is an efficient electrocatalyst with superior electrocatalytic performance towards overall water splitting that can be useful at the industrial scale.