It is still a great challenge to find highly efficient non-Pt catalysts with good stability for the hydrogen evolution reaction (HER). The molybdenum phosphide (MoP)-based catalysts have been identified as promising candidates to replace noble Pt, but the further improvement of these catalysts is still strongly demanded. Herein, a simple strategy to enhance the HER activity of the MoP catalyst has been proposed, in which a novel MoP/C hybrid is prepared by a facile temperature-programmed reduction method with the modification of Ketjen Black, exhibiting superior HER activity with a smaller Tafel slope of 54 mV dec−1 and a larger current density of 151 mA cm−2 at −400 mV, about 34 times larger than that of the pure MoP catalyst. Moreover, a possible improvement mechanism was also stated.

•The N-doped MoP nanoparticles are prepared by addition of nitrilotriacetic acid.•The addition of nitrilotriacetic acid results in reduced electrical resistance.•The N-doped MoP nanoparticles possess more active sites with higher quality.It is still strongly required to explore non-noble catalysts with excellent performances for hydrogen generation. MoP-based catalysts are demonstrated as good candidates and further improvements are highly encouraged. Herein, a novel strategy of N-doping has been proposed to increase the HER performance over the MoP-based catalysts, in which nitrilotriacetic acid (N(CH2COOH)3, NTA) is selected to provide the doping element of N. With the addition of NTA, the N-doped MoP catalysts with good distribution have been successfully prepared, showing smaller particle size, reduced electrical resistance, increased amount and better quality of active sites, resulting in much better performances compared to pure MoP. This strategy can also be extended to other counterparts for the further improvement of HER activity by N-doping.

MoS2 nanodot decorated In2S3 nanoplates were successfully synthesized via a modified one-pot method. The In2S3/MoS2 heterojunction nanocomposite exhibits superior optical and photoelectrochemical performance to the bare ones, owing to the synergistic effect.

Co-promoted molybdenum phosphide nanoparticles have been successfully prepared and explored for the first time as a cost-effective electrocatalyst for hydrogen evolution reaction (HER). The as-developed catalyst demonstrates excellent HER activity with a small Tafel slope of 50 mV dec−1 which is among the best records reported for MoP-based catalysts. The addition of Co not only reduces the particle size of the MoP-based catalyst and promotes the charge transfer, but also enhances the intrinsic activity of each active site, paving the way for optimizing the HER performances of ternary or multiple transition metal phosphide catalysts.

The replacement of Pt with cheap metal electrocatalysts with high efficiency and superior stability for the hydrogen evolution reaction (HER) remains a great challenge. Furthermore, the optimization of MoS2 electrocatalysts has attracted much attention. In this work, we report a simple strategy to enhance the HER ability of MoS2 catalysts via the doping of nickel. With the doping of a small amount of nickel, the MoS2 catalyst shows more electrochemical active sites, higher turnover frequency over each active site and better conductivity, resulting in excellent HER activity with a small Tafel slope of 47 mV dec−1, making it a promising HER electrocatalyst for practical applications.

A highly active and stable electrocatalyst (MoSx@Mo2C) for hydrogen evolution is developed via the sulfur decoration of molybdenum carbide for the first time. Although the decoration of sulfur reduced the electrochemically active surface area and slightly enlarged the impedance resistance of Mo2C substrates, the turnover frequency was remarkably enhanced, resulting in a great improvement in the final hydrogen evolution reaction activity. More importantly, there is a synergistic effect between MoSx and Mo2C, making the MoSx@Mo2C catalyst exhibit an excellent activity with a small Tafel slope of 44 mV dec–1, which is among the best records for Mo2C-based catalysts.Keywords: hydrogen evolution reaction; molybdenum carbide; molybdenum disulfide; sulfuration; synergistic effect

•β-Mo2C nanoparticles have been successfully prepared.•β-Mo2C nanoparticles possess a high specific BET surface area of 120 m2 g−1.•β-Mo2C nanoparticles exhibit excellent activity and stability in the HER.•A relatively small Tafel slope of 55 mV/dec was obtained.•η-MoC could be obtained at 800 °C with a reduction time of 10 min.Mo2C nanoparticles with high specific surface area (120 m2 g−1) are successfully synthesized using a typical and low-cost monosaccharide of glucose via a facile calcination and subsequent reduction process. The HER functions of the obtained Mo2C nanoparticles are investigated and the effect of reduction time in hydrogen is also discussed. It is found that η-MoC can be obtained at 800 °C with a reduction time of 10 min, but the formation of β-Mo2C phase requires more than 20 min. Moreover, the β-Mo2C obtained with a reduction time of 20 min exhibits the best HER activity with a small Tafel slope of 55 mV dec−1 and a large current density of 60 mA cm−2 at −200 mV, which is among the best records over Mo2C-based HER catalysts.

Molybdenum phosphide was adopted as a new electrocatalyst for the hydrogen evolution reaction for the first time, exhibiting an excellent electrocatalytic activity with a small Tafel slope of 60 mV dec−1, which is amongst the most active, acid-stable, earth abundant HER electrocatalysts reported to date.

•Amorphous MoS2 nanoflowers have been successfully prepared by a hydrothermal method.•Amorphous MoS2 nanoflowers exhibit excellent activity and stability in the HER.•A relatively low Tafel slope of 52 mV dec−1 was obtained.•A small onset potential of −130 mV was also observed.Amorphous MoS2 nanoflowers assembled by lamellar nanosheets have been successfully synthesized by a facile hydrothermal method. They were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and evaluated as electrochemical catalysts in the hydrogen evolution reaction (HER). Moreover, the effect of preparation temperature was also discussed. It was found that these catalysts exhibited excellent HER activity compared to commercial bulk MoS2 microparticles due to the special structure of nanoflowers assembled by nanosheets with few layers, exposing much more active sites and reducing intrinsic resistance. And the catalyst obtained at 220 °C showed the best activity with the largest exchange current density and the smallest Tafel slope of 52 mV dec−1, which made it a promising HER electrocatalyst for practical applications.

•First report on distorted MoS2 nanostructures as an efficient HER catalyst.•The distorted structures with an abundance of exposed edge sites.•The pretreatment of ball milling enhanced the intrinsic activity of each site.•A small onset potential of 103 mV was observed.An effective electrochemical catalyst has been developed through a mechanical activation method for the hydrogen evolution reaction (HER). Catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area measurements. It was found that the mechanical activated MoS2 (MA-MoS2) possessed distorted structures with an abundance of exposed edge sites, exhibiting excellent electrochemical activity in the HER with a high current density and a relatively low Tafel slope.

•The CoMoP catalysts have been successfully prepared by a simple TPR method.•The optimized Mo/P molar ratio was 1:2 with an outstanding Tafel slope of 50 mV/dec.•The variation of Mo/P molar ratios influenced the particle size, BET surface area and resistance.•The resistance was significantly reduced with the optimized Mo/P molar ratio.Uniform unsupported Co-promoted MoP catalysts for the hydrogen evolution reaction (HER) were synthesized via a facile temperature-programmed reduction (TPR) of the corresponding metal phosphate salts, and the effect of Mo/P ratio was also investigated. It is found that the Mo/P ratio plays a crucial role in the final HER activity, and the CoMoP catalyst with a Mo/P molar ratio of 1:2 exhibits the best HER activity with a small Tafel slope of 50 mV per decade and a very low onset potential of −85 mV in 0.5 M H2SO4.Download high-res image (120KB)Download full-size image

•The Ag wrapped MoS2 hybrid was prepared by a simple silver mirror reaction.•The Ag@MoS2 hybrid exhibits a large specific capacitance of 980 F g−1 at 1 A g−1.•The Ag@MoS2 hybrid possesses a high retention ratio of 97% after 5000 cycles.•The optimized mole ratio of Ag: MoS2 is 1: 8, resulting in the best performances.A simple and facile silver mirror reaction is introduced to wrap MoS2 nanosheets with highly conductive Ag. With the assistance of Ag, the electron transfer ability of the MoS2 matrix is enhanced, leading to outstanding electrochemical storage ability. The influence of Ag content is also investigated. It is found that the optimized mole ratio of Ag: MoS2 is 1: 8, resulting in the maximal specific capacitance of 980 F g−1 at 1 A g−1. Moreover, the cycling stability is also very good with a high retention of 97% for 5000 cycles. Therefore, the obtained Ag@MoS2 hybrid shows potential applications in the supercapacitors. The current strategy also paves a way for the design and optimization of MoS2-based materials for other applications in lithium battery, electrochemical and photo-electrochemical catalysts.

•CoNi2S4 nanoparticles were successfully prepared through a hydrothermal method.•CoNi2S4 nanoparticles were demonstrated to be highly efficient HER catalysts.•The HER activity of CoNi2S4 was strongly affected by the preparation temperature.•The optimized preparation temperature is 220 °C with the best HER activity.The development of highly active non-Pt electrocatalysts with superior stability for the hydrogen evolution reaction (HER) remains a great challenge. Herein, we report CoNi2S4 nanoparticles synthesized by a facile one-pot hydrothermal method as highly efficient electrocatalysts for the HER in strongly alkaline electrolyte for the first time, and the effect of preparation temperature was also discussed systematically. These as-prepared catalysts exhibited superior HER activity compared to other non-noble metal catalysts and the catalyst obtained at 220 °C showed the best activity with the smallest Tafel slope of 85 mV dec−1 and good stability in 1.0 M KOH, making it a promising candidate to replace Pt-based catalysts.

Co-promoted molybdenum phosphide nanoparticles have been successfully prepared and explored for the first time as a cost-effective electrocatalyst for hydrogen evolution reaction (HER). The as-developed catalyst demonstrates excellent HER activity with a small Tafel slope of 50 mV dec−1 which is among the best records reported for MoP-based catalysts. The addition of Co not only reduces the particle size of the MoP-based catalyst and promotes the charge transfer, but also enhances the intrinsic activity of each active site, paving the way for optimizing the HER performances of ternary or multiple transition metal phosphide catalysts.

MoS2 nanodot decorated In2S3 nanoplates were successfully synthesized via a modified one-pot method. The In2S3/MoS2 heterojunction nanocomposite exhibits superior optical and photoelectrochemical performance to the bare ones, owing to the synergistic effect.

Molybdenum phosphide was adopted as a new electrocatalyst for the hydrogen evolution reaction for the first time, exhibiting an excellent electrocatalytic activity with a small Tafel slope of 60 mV dec−1, which is amongst the most active, acid-stable, earth abundant HER electrocatalysts reported to date.