Exceptional Performance of MOF-Derived N-Doped CoP and Fe-Doped CoOOH Ultrathin Nanosheets Electrocatalysts for Overall Water Splitting

Electrochemical water splitting is deemed as an important and sustainable technology for hydrogen generation. Searching for low-cost and efficient electrocatalysts toward hydrogen/oxygen evolution reaction (HER/OER) is of great importance for commercial application of water electrolysis. Cobased phosphides and oxides/hydroxides are extensively developed as HER and OER electrocatalysts, respectively. Herein, a novel strategy is developed to prepare a self-supported N-doped CoP ultrathin nanosheets (namely N-Co-Ni-P/Ni) for HER and Fe-doped CoOOH nanosheets (namely Fe-Co-OOH/Ni) for OER based on the MOF-derived Co(OH)(2) nanosheets, along with short lateral size caused by Co-MOF confinement growth. The self-supported N-Co-Ni-P demands an overpotential of 50 mV to deliver a current density of 10 mA cm(-2) in alkaline conditions (1M) for HER The self-supported Fe-Co-OOH nanosheet electrocatalysts also exhibit high catalytic activity for OER. The experimental measurements demonstrate that the increased positive charge of Co atoms caused by the introduction of N atoms can significantly enhance HER performance. Moreover, the large surface areas, high exposure of active sites, and effective mass transport channels are also favorable to improved catalytic activity. The electrolyzer with N-Co-Ni-P/Ni and Fe-Co-OOH shows excellent activity with an electrolysis voltage of 1.51 Vat 10 mA cm which is superior to the Pt(-)//Ir/Ta (+) electrolyzer (1.62 V).