Abstract
Two-dimensional transition-metal dichalcogenides (TMDs) possess interesting catalytic properties for the electrochemical-assisted hydrogen-evolution reaction (HER). We used niobium diselenide (NbSe2) as a representative TMD, and prepared single-layer NbSe2 porous nanosheets (PNS) by a double-sonication liquid-phase exfoliation, with H2O2 as a pore-forming agent. The single-layer NbSe2 PNS were drop-cast on carbon foam (CF) to fabricate a three-dimensional robust NbSe2 PNS/CF electrode. The NbSe2 PNS/CF electrode exhibits a high current density of −50 mA cm−2 with an overpotential of 148 mV and a Tafel slope of 75.8 eV dec−1 for the HER process. Little deactivation is detected in continuous CV testing up to 20,000 cycles, which suggests that this novel NbSe2 PNS/CF is a promising catalytic electrode in the HER application. The porous structure of single-layer NbSe2 nanosheets can enhance the electrochemical performance compared with that of pore-free NbSe2 nanosheets. These findings illustrate that the single-layer NbSe2 PNS is a potential electrocatalytic material for HER. More importantly, the electrochemical performance of the NbSe2 PNS/CF expands the use of two-dimensional TMDs in electrocatalysis-related fields.
Highlights
The energy crisis has aroused extensive research interest in the search for sustainable energy-conversion systems that exhibit a high productivity and low cost
The Cdl of NbSe2 porous nanosheets (PNS)/carbon foam (CF) is more than twice that of NbSe2 NSs/CF (5.35 versus 2.3 mF cm−2), whereas the Cdl of the NbSe2 bulk/CF and pure CF is only 0.61 and 0.19 mF cm−2, respectively. These results show that NbSe2 PNS/CF possesses more hydrogen-evolution reaction (HER) active sites than that of the NbSe2 NSs/CF because more basal planes were exposed in this typical porous structure
The single-layer porous NbSe2 nanosheets were loaded on the CF surface as efficient electrocatalytic electrodes for HER
Summary
The energy crisis has aroused extensive research interest in the search for sustainable energy-conversion systems that exhibit a high productivity and low cost. The development of nonprecious-metal catalysts that drive HER at a low overpotential with an excellent reaction efficiency is essential for large-scale production of hydrogen through electrochemical water splitting [15,16]. Two-dimensional (2D) transition-metal dichalcogenides (TMDs), such as MoS2 and WS2, have attracted much attention because of their layer structure and excellent electrocatalytic properties [17]. The Group V NbSe2 TMDs are prized for their low-dimensional crystal structure and exhibit interesting electronic properties, such as superconductivity, charge density waves and Mott transition [24]. Little deactivation has been detected in stability testing, even up to 20,000 cycles, which reveals the promising prospect of this novel single-layer NbSe2 porous nanosheets/carbon in massive electrochemical water splitting and hydrogen production
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