Nitrogen doped MoS2 nanosheets synthesized via a low-temperature process as electrocatalysts with enhanced activity for hydrogen evolution reaction

doi:10.1016/j.jpowsour.2017.04.060

Journal of Power Sources

Volume 356, 15 July 2017, Pages 133-139

https://doi.org/10.1016/j.jpowsour.2017.04.060 Get rights and content

Highlights

•
A simple strategy was reported to fabricate N-doped MoS₂ as HER catalysts.
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N-doped MoS₂ revealed an enhanced HER performance than pure MoS₂.
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The DFT confirmed that more active sites were produced by doped N atoms.

Abstract

Highly active and earth-abundant catalysts for hydrogen evolution reaction (HER) play a crucial in the development of efficient water splitting to produce hydrogen fuel. Here, we reported a simple, facile and effective strategy to fabricate N-doped molybdenum sulfide (N-doped MoS₂) as noble metal-free catalysts for HER. Compared with pure MoS₂, the obtained N-doped MoS₂ catalyst revealed enhanced HER performance with low overpotential of −168 mV (−10 mA cm⁻²), small Tafel slope of 40.5 mV dec⁻¹ and excellent stability. The superior HER activity may originate from both the exposed Mo active sites due to S defects and the optimized electron density state of S atoms by N doping. More importantly, due to its simple synthesis method, earth-abundant catalysts and high catalytic activity, the N-doped MoS₂ will become a promising HER catalysts for water splitting.

Graphical abstract

Introduction

Hydrogen (H₂), as a clean and promising energy, has received tremendous interest due to the increasing environmental concerns and consumption of fossil fuels [1], [2], [3], [4]. The hydrogen evolution reaction (HER) from water splitting has been widely regarded as a sustainable clean pathway for hydrogen production [5], [6], [7], [8]. During HER process, the catalyst plays an essential role in reducing overpotential, promoting the reaction kinetics and thus enhancing the HER catalytic efficiency. Pt-based catalysts have been so far the most efficient catalysts for HER, but their high cost and scarcity have hampered its widespread applications [9], [10], [11], [12], [13]. Therefore, it remains a hugely challenge to develop the inexpensive and earth-abundant catalyst within good catalytic property and high cycling stability.

Recently, transition metal sulfides (MoS₂, WS₂ et al.) [13], [14], [15], [16], [17], [18] have been intensively investigated as HER catalysts. Theoretical and experimental studies have indicated that Mo and S edges of MoS₂ are catalytically active sites for HER [19], [20], [21]. To improve the HER catalytic activity of MoS₂, some general strategies have been attempted [22], [23], [24], [25], [26], [27], [28], including the controlled particle size/morphology, improved electrical conductivity, composite effect and element doping, etc. Note that element doping is one of the effective methods to rationally optimize HER activity of MoS₂ by changing the atomic arrangement and electron density state [29], [30], [31]. It has been reported that metal (such as Co, Ni, Fe and Cu) [30], [31] or non-metal (N, P, O, Se, Cl et al.) [32], [33], [34], [35] atoms were doped to replace Mo or S atoms, respectively, which modified their electronic properties and boost intrinsic conductivity. Sun et al. [32] have developed a flower-like N-doped WS₂ which were synthesized by the sol–gel process and subsequent annealing treatment. N-doping could introduce more charge carriers and improve the intrinsic conductivity and thus revealed the enhanced electrochemical HER activity. Nevertheless, to the best of our knowledge, majority of N atoms doping required complicated and multi-step process, such as high-temperature calcination [36] or harsh requirement (N₂ plasma) [37], [38]. Therefore, it would be worthwhile to design a relatively simple, low-temperature and efficient approach for the preparation of N atoms doped MoS₂ to obtain enhanced HER performance.

Here, we developed a nitrogen doped MoS₂ (N-doped MoS₂) as an efficient catalyst for HER by simple hydrothermal reaction. By incorporation of nitrogen atom (replace S atom), more active edge sites were exposed and thus enhanced catalytic performance of MoS₂. The theoretical calculations confirmed that the active sites in N-doped MoS₂ were S atoms tuned by N doping and Mo atoms tuned by S defects. As expected, the obtained N-doped MoS₂ presented an enhanced HER catalytic activity with low overpotential of -168 mV (-10 mA cm^-2), small Tafel plot of 40.5 dec mV^-1 and superior long-term stability.

Section snippets

Experimental section

Chemicals: ammonium tetrathiomolybdate ((NH₄)₂MoS₄), dicyandiamide (C₂H₄N₄) and iso-Propyl alcohol (C₃H₈O) were purchased from Sinopharm Chemical Reagents Beijing Co. All of the reagents were of analytical grade and used without further treatment. Deionized (D.I.) water was purified using a Milli-Q system (Millipore, Billerica, USA).

Results and discussion

The N-doped MoS₂ and MoS₂ were synthesized by simple hydrothermal reaction at reactively low temperature. The crystalline nature of obtained materials was investigated by powder X-ray diffraction (XRD). As shown in Fig. 1a, the obtained MoS₂ showed four peaks at 14.1°, 33.4° 40.0° and 58.9°, corresponding to the (002), (100) (103) and (110) lattice plane, agreeing well with the standard pattern of hexagonal MoS₂ (JCPDS card No. 73-1508) [16]. Nevertheless, after doping nitrogen, the (002) peak

Conclusion

In summary, we have developed an effective and low-temperature synthesis method to prepare the N-doped MoS₂ as efficient electrocatalysts for HER. By introducing nitrogen atoms, 1) the N-doped MoS₂ revealed more homogeneous than pure MoS₂, resulting in the higher electrochemical active area; 2) more Mo active sites were exposed by abundant defects and the ΔGH* of S atoms were simultaneously tuned by doped N atoms. Thus, compared with pure MoS₂, the N-doped MoS₂ become more active for HER and

Acknowledgment

This work was supported by Project of Public Interest Research and Capacity Building of Guangdong Province (2014A010106005), Guangdong Innovative and Entrepreneurial Research Team Program (2014ZT05N200) and the National Natural Science Foundation of China (51502096).

References (46)

D. Hou et al.
Electrochim. Acta
(2015)
H. Li et al.
Nat. Mater.
(2016)
L. Yang et al.
Nano Energy
(2016)
W. Fu et al.
Nano Energy
(2016)
G. Kresse et al.
Comput. Mater. Sci.
(1996)
Y. Hou et al.
Energy Environ. Sci.
(2016)
J. Lai et al.
Energy Environ. Sci.
(2016)
J. Huang et al.
J. Mater. Chem. A
(2015)
L. Yang et al.
Nanoscale
(2015)
X. Zou et al.
Chem. Soc. Rev.
(2015)

X. Yu et al.

Nanoscale

(2016)

L. Jiao et al.

Chem. Sci.

(2016)

J.X. Feng et al.

Adv. Mater.

(2015)

B. Liu et al.

Angew. Chem. Int. Ed.

(2016)

W. Xi et al.

J. Mater. Chem. A

(2016)

B. Bayatsarmadi et al.

Small

(2016)

C.K. Ranaweera et al.

J. Mater. Chem. A

(2016)

B. You et al.

Adv. Energy Mater.

(2016)

W. Zhou et al.

Acs Appl. Mater. Inter.

(2014)

J. Xie et al.

Adv. Mater.

(2013)

G.F. Chen et al.

Adv. Funct. Mater.

(2016)

H. Zhou et al.

J. Mater. Chem. A

(2016)

J. Ekspong et al.

Adv. Funct. Mater.

(2016)

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¹: These authors contributed equally to the work.

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Nitrogen doped MoS2 nanosheets synthesized via a low-temperature process as electrocatalysts with enhanced activity for hydrogen evolution reaction

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Experimental section

Results and discussion

Conclusion

Acknowledgment

Electrochim. Acta

Nat. Mater.

Nano Energy

Nano Energy

Comput. Mater. Sci.

Energy Environ. Sci.

Energy Environ. Sci.

J. Mater. Chem. A

Nanoscale

Chem. Soc. Rev.

Nanoscale

Chem. Sci.

Adv. Mater.

Angew. Chem. Int. Ed.

J. Mater. Chem. A

Small

J. Mater. Chem. A

Adv. Energy Mater.

Acs Appl. Mater. Inter.

Adv. Mater.

Adv. Funct. Mater.

J. Mater. Chem. A

Adv. Funct. Mater.

Nitrogen doped MoS₂ nanosheets synthesized via a low-temperature process as electrocatalysts with enhanced activity for hydrogen evolution reaction