Exposing highly active (100) facet on a SnS2/SnO2 electrocatalyst to boost efficient hydrogen evolution.

[Display omitted] • Design and synthesis of (100) facet exposed SnS 2 /SnO 2 heterostructures. • Efficient hydrogen production on the (100) facet. • Experimental and theoretical clarification of boosted hydrogen generation. Tin disulfide (SnS 2), one transition metal dichalcogenide (TMD) is a cost-effective and promising electrocatalyst for hydrogen evolution reactions (HER) in the alkaline electrolytes. Its electrocatalytic HER performance is unfortunately limited, originating from its un-conspicuous inherent catalytic activities and non-favorable adsorption sites for hydrogen. Herein, a tin disulfide/stannic oxide (SnS 2 /SnO 2) heterostructure is designed and grown on the nickel foam (denoted as SnS 2 /SnO 2 -NF). The SnS 2 /SnO 2 heterostructure introduces more active (100) facets or a high density of active sites, accelerates the diffusion kinetic of electrons and ions, lowers the water dissociation energies, and optimizes adsorption energies of hydrogen atoms. On this catalyst, superior HER performance is realized in an alkaline medium. An overpotential of 108 mV at a current density of −10 mA cm–2 with a Tafel slope of 50.1 mV dec–1 and long-term durability are achieved for HER in 1 M KOH. This work paves a new way to design high-performance HER electrocatalyst through facet engineering of the designed heterostructures. [ABSTRACT FROM AUTHOR]