SnO2@MoS2 heterostructures grown on nickel foam as highly efficient bifunctional electrocatalyst for overall water splitting in alkaline media

A novel nanoforest-like SnO2@MoS2/Ni foam electrode was devised and manufactured using a simple two-step hydrothermal technique. Arrays of the rutile-type SnO2 nanorods were grown perpendicularly to the Ni foam (NF) skeleton surface with a mean diameter of ca. 40 nm and lengths up to around 300 nm; then, MoS2 nanosheets were decorated on the SnO2 nanorods to form 3D self-supporting nanoforest-like SnO2@ MoS2 heterostructures. The SnO2@MoS2/NF heterostructure catalyst delivered 10 mA cm-2 at an over-potential of 127 mV for the hydrogen evolution reaction (HER) and 50 mA cm-2 at an overpotential of 290 mV for the oxygen evolution reaction (OER) in 1.0 M KOH. The unique SnO2@MoS2 heterostructures and synergistic effects of MoS2 and SnO2 improved the catalytic activity for both HER and OER. Furthermore, this bifunctional electrode provides high-efficiency alkaline water electrolysis with 10 mA cm-2 at 1.57 V cell voltage and exceptional long-term electrochemical stability with 98.3 % current preservation after 300 h of testing. The SnO2@MoS2 heterostructures can act as an efficient bifunctional electrocatalyst for overall water splitting with superior activity and excellent durability. This innovative work may offer important implications for rational design and construction of 3D self-supporting bulk electrode materials for overall water splitting.(c) 2022 Elsevier B.V. All rights reserved.