Self-supported hierarchical P,Cu-codoped cobalt selenide nanoarrays for enhanced overall water splitting

Highly efficient electrocatalysts with low cost for electrochemical water splitting is important for the intermediate energy conversion. In the present work, P and Cu dual-doped cobalt selenide nanoarrays with hierarchical structure were fabricated via a facile hydrothermal method, involving in-situ growth on a self-supported conductive Ni foam substrate (P,Cu-Co0.85Se/NF). The overall water splitting (OWS) performance of the catalysts was systematically studied in alkaline solution. Compared to single-ion-doped or pure Co0.85Se, dual incorporation of the anion and cation can contort the lattice and induce powerful electronic interactions, thereby exposing abundant catalytic sites and optimizing the adsorption energy of the reaction intermediates. Benefiting from the merits of P, the Cu-co-doped Co0.85Se/NF electrode exhibited outstanding catalytic activity towards hydrogen evolution reaction (HER), generating a 10 mA cm−2 current density at the overpotential of 96.8 mV in 1 M KOH, and the overpotential is 300 mV towards oxygen evolution reaction (OER) with the current density of 100 mA cm−2. Furthermore, when applied it to fabricate OWS cell, the cell voltage is as low as 1.57 V at the current density of 10 mA cm−2. This present work broaden the potential application of the electrocatalytic performance of transition metal dichalcogenides.