Coupling Interface Constructions of MoS2 /Fe5 Ni4 S8 Heterostructures for Efficient Electrochemical Water Splitting.

Water splitting is considered as a pollution-free and efficient solution to produce hydrogen energy. Low-cost and efficient electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are needed. Recently, chemical vapor deposition is used as an effective approach to gain high-quality MoS2 nanosheets (NSs), which possess excellent performance for water splitting comparable to platinum. Herein, MoS2 NSs grown vertically on FeNi substrates are obtained with in situ growth of Fe5 Ni4 S8 (FNS) at the interface during the synthesis of MoS2 . The synthesized MoS2 /FNS/FeNi foam exhibits only 120 mV at 10 mA cm-2 for HER and exceptionally low overpotential of 204 mV to attain the same current density for OER. Density functional theory calculations further reveal that the constructed coupling interface between MoS2 and FNS facilitates the absorption of H atoms and OH groups, consequently enhancing the performances of HER and OER. Such impressive performances herald that the unique structure provides an approach for designing advanced electrocatalysts.