Engineering multiphasic MoSe2/NiSe heterostructure interfaces for superior hydrogen production electrocatalysis

Constructing heterojunction nanocomposites with optimized active sites and interface electronic structures is promising for hydrogen evolution reaction (HER). Herein, we present an interface engineering strategy to fabricate two heterostructures, triphase MoSe 2 /NiSe-1 including 1T-MoSe 2 , 2H-MoSe 2 and hexagonal phase NiSe (H-NiSe), and tetraphase MoSe 2 /NiSe-2 including 1T-MoSe 2 , 2H-MoSe 2 , H-NiSe and rhombohedral phase NiSe (R-NiSe). MoSe 2 /NiSe-1 exhibited remarkably enhanced HER activity with an overpotential of 30 mV at 10 mA cm −2 , and negligible voltage change even when operated for 40 h. The strong electronic synergistic interaction between the different interfaces of mixed MoSe 2 /NiSe greatly enhanced the HER performance. Density functional theory calculations helped rationalize why the combination of three phases is more active, by increasing the interface electron concentration, facilitating electron transfer and decreasing the free energy ΔG H2O and ΔG H* . This work provides a rational strategy to design and assemble stable and high-performance multiphasic heterojunctioned HER electrocatalysts. • Two rare multiphasic heterojunctions are fabricated by interface engineering. • Triphase MoSe 2 /NiSe-1 exhibited excellent HER activity (30 mV at 10 mA cm −2 ). • MoSe 2 /NiSe-1 showed long-term durability with negligible voltage change for 40 h. • DFT calculations shed light on the key parameters for improved HER activity. • This work provides in-depth understanding of the structure-activity relationship.