Novel core-shell structured electrocatalyst with 1D-NiTe2 over 3D metal structure for efficient hydrogen evolution reactions

Abstract

Novel inexpensive materials are the focus of modern research for efficient hydrogen evolution reactions (HER) to substitute scarce and expensive platinum (Pt) based electrocatalysts. The ideal material should be durable, low-cost, efficient and possess high surface area. Earth abundant Transition metal dichalcogenides (TMDCs) are the potential group of materials for providing inexpensive source of durable HER catalysts with high surface area and active edges due to their layered structure. Here, we report a scalable single-step microwave-assisted solution phase synthesis of NiTe2 with core-shell configuration over porous three-dimensional nickel foam (3D-NF). This surface heterojunction catalyst possesses high surface area, unique needlelike morphology, and efficient performance for hydrogen evolution reactions. NiTe2 needles decorated on porous 3D-NF displayed fast HER kinetics with a reasonable overpotential of ~ −0.36 V to drive a current density of 100 mA cm−2. A small Tafel slope of ~55 mV dec−1 is observed. The catalyst showed higher stability with negligible performance degradation even after 8 h of potential cycling operation. It also demonstrated negligible current density variation at a constant applied potential for more than 15 h in 0.5 M sulfuric acid (H2SO4) solution. The 3D porous skeleton allowed high impregnation of electrolyte while the dense needlelike morphology provided high surface area and active edge sites for reactions. A thin 7 nm of amorphous oxide overlayer shell on highly crystalline NiTe2 core structure makes it a surface heterojunction catalyst (SHC) which is reported to facilitate hydrogen desorption upon charge take up and makes it an efficient electrocatalyst.