Heterostructure nanohybrids of Ni-doped MoSe2 coupled with Ti2NTx toward efficient overall water splitting

We propose a Ni doped MoSe2/Ti2NTx MXene nanosheet heterostructure engineering (represented as Ni–MoSe2/Ti2NTx) with low cost and high efficiency as an electrocatalyst, which can stably perform bifunctional overall water splitting for a long time. Ti2NTx as a 2D conductive substrate can promote electron transfer and avoid MoSe2 agglomeration, and MoSe2 has rich active sites. The purpose of doping metal Ni is to adjust the electronic structure of the MoSe2/Ti2NTx heterojunction effectively and further improve the Ni–MoSe2/Ti2NTx catalytic activity. Therefore, the Ni–MoSe2/Ti2NTx catalyst in alkaline media exhibits excellent catalytic and synergistic effects in terms of the activities of both hydrogen and oxygen evolution reactions (HER and OER). In short, Ni–MoSe2/Ti2NTx exhibits overpotential as low as 92 mV at a current density of 10 mA cm−2 and Tafel slope (79.7 mV dec−1) for HER performance in alkaline media. In terms of OER performance, Ni–MoSe2/Ti2NTx displays remarkable overpotential (270 mV at 50 mA cm−2) and Tafel slope (81.1 mV dec−1). In overall water splitting configuration, Ni–MoSe2/Ti2NTx electrodes used as bifunctional electrocatalysts only need 1.59 V at 10 mA cm−2. The Ni–MoSe2/Ti2NTx heterostructure engineering with excellent durability is instructive to the overall water splitting configuration.