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• Co doped MoS 2 was decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) by a solvothermal process. • The lattice spacing of (1 0 0) plane of Co-MoS 2 was slightly narrow than that of MoS 2. • The as-prepared Co-MoS 2 /NCFCP hybrids showed enhanced electrochemical activity for HER. In this paper, Co-doped MoS 2 (Co-MoS 2) with various Co/Mo mole ratio (6%–12%) decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) (Co-MoS 2 /NCFCP) is fabricated by a solvothermal method as an efficient electrocatalyst for hydrogen evolution reaction (HER). The NCFCP substrate is prepared by electrochemical deposition of polypyrrole on carbon paper followed by heat treatment. The obtained 9% Co-MoS 2 /NCFCP hybrid catalyst exhibits an excellent electrocatalytic HER activity with a low overpotential of 174 mV at 10 mA cm−2, a small Tafel slope of 52 mV dec−1 and long-term stability. Thus, Co-MoS 2 /NCFCP hybrid holds high potential as an efficient earth-abundant electrocatalyst material for HER. [ABSTRACT FROM AUTHOR]

As the cost-effective and nontoxic alternative for hydrogen evolution reaction (HER), Co 9 S 8 has attracted much attention. This paper explores the regulation of Zn doping impacted the unique nanostructure and electrocatalytic performance on Co 9 S 8. Herein, utilizing copper foam (CF) as substrate, a series of different nanostructure of (Zn-)Co 9 S 8 @CF has been synthesized by accurately varying the ratio of Zn2+ to Co2+. Compared with aggregated pure Co 9 S 8 and other different ratios contrast samples, Zn–Co 9 S 8 @CF-(1-1) with a zinc to cobalt ratio of 1 possesses highly dispersity which can be attributed to the novel nano-neuron network structure. The electrochemical measurements for HER demonstrate that Zn–Co 9 S 8 @CF-(1-1) not only reveals superior activity with small overpotentials to achieve a current density of 10 mA cm−2 in acidic (278 mV) and alkaline (273 mV) media, but also exhibits long-time durability in the solution with a wide range of pH. The excellent performance of Zn–Co 9 S 8 @CF-(1-1) can be attributed to the unique reticular structure which can facilitate exposure of numerous active sites and favorable long-term stability. The substrate of three-dimensional CF can provide the remarkable conductivity. This work provides a precise and effective approach to regulate three-dimensional nanostructure of Zn-doped electrocatalysts for HER. Image 1 • Zn–Co 9 S 8 on copper foam (CF) with a nano-neuron network structure is synthesized. • The ratios of Zn2+ to Co2+ can affect the structure of Zn–Co 9 S 8 @CF. • Zn–Co 9 S 8 @CF exhibits excellent activity and long-time durability with a wide range of pH. • Zn doping is a promising method for construct the novel structure of electrocatalysts. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2) is one of the promising candidates for hydrogen evolution reaction (HER), it's HER properties can be extremely enhanced by the construction of nanostructure and the regulation of electronic structure. In this paper, hierarchical composites with MoS 2 and carbon nanotubes (CNTs) as the noble metal-free electrocatalysts for HER were fabricated through calcination and hydrothermal processes, in which the MoS 2 nanosheets with Ni atoms incorporation were vertically grown on the outsides of nitrogen (N)-doped CNTs. The constructed hierarchical structures provide large specific surface area of about 150 m2 g−1 and high structure stability. Importantly, the MoS 2 nanosheets with enlarged interlayer spacing possess ultrathin structure of about 4 nm in thickness. Owing to the incorporation of Ni atoms, abundant unsaturated S atoms are obtained in the basal plane, which leading to more active sites exposed during HER processes. Meanwhile, N-doped CNTs can act as the substrate for MoS 2 nanosheets growing and simultaneously improve the conductivity of catalyst. Based on the synergy of hierarchical structure, increased active sites and enhanced conductivity, the as-prepared electrocatalysts exhibit superior HER activity with low overpotentials, small Tafel slopes and long-time durability in both acidic and alkaline electrolytes. The overpotentials of 158 and 179 mV were required to drive HER current density up to 10 mA cm−2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. This work reports a highly efficient MoS 2 -based electrocatalyst for HER via fabricating hierarchical structure and doping Ni atoms. Image 1 [ABSTRACT FROM AUTHOR]