Molybdenum sulfide (MoS2) has emerged as a promising electrocatalyst for hydrogen evolution reaction (HER) owing to its high activity and stability during the reaction. However, the efficiency of hydrogen production is limited by the number of active sites in MoS2. In this work, a simple method of fabricating polycrystalline multilayer MoS2on Mo foil for efficient hydrogen evolution is demonstrated by controlling the sulfur (S) vacancy concentration, which can introduce new bands and lower the hydrogen adsorption free energy (Δ
Solid‐state electrocatalysis plays a crucial role in the development of renewable energy to reshape current and future energy needs. However, finding an inexpensive and highly active catalyst to replace precious metals remains a big challenge for this technology. Here, tri‐molybdenum phosphide (Mo3P) is found as a promising nonprecious metal and earth‐abundant candidate with outstanding catalytic properties that can be used for electrocatalytic processes. The catalytic performance of Mo3P nanoparticles is tested in the hydrogen evolution reaction (HER). The results indicate an onset potential of as low as 21 mV, H2formation rate, and exchange current density of 214.7 µmol s−1g−1cat(at only 100 mV overpotential) and 279.07 µA cm−2, respectively, which are among the closest values yet observed to platinum. Combined atomic‐scale characterizations and computational studies confirm that high density of molybdenum (Mo) active sites at the surface with superior intrinsic electronic properties are mainly responsible for the remarkable HER performance. The density functional theory calculation results also confirm that the exceptional performance of Mo3P is due to neutral Gibbs free energy (Δ
- Award ID(s):
- 1809439
- NSF-PAR ID:
- 10461091
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Energy Materials
- Volume:
- 9
- Issue:
- 22
- ISSN:
- 1614-6832
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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G H). For the first time, theoretical and experimental results show that the HER performance of synthesized MoS2with S vacancy can be further enhanced by the very small amount of platinum (Pt) decoration, which can introduce new gap states and more catalytic sites in real space with suitable free energy. The fabricated hybrid electrocatalyst exhibits significantly smaller Tafel slope of 38 mV dec−1and better HER electrocatalytic activity compared to previous works. This approach provides a simple pathway to design low‐cost, efficient and sizable hydrogen‐evolving electrode by simultaneously tuning the MoS2band structure and active sites. -
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Abstract Nickel sulfide (Ni3S2) is a promising hydrogen evolution reaction (HER) catalyst by virtue of its metallic electrical conductivity and excellent stability in alkaline medium. However, the reported catalytic activities for Ni3S2are still relatively low. Herein, an effective strategy to boost the H adsorption capability and HER performance of Ni3S2through nitrogen (N) doping is demonstrated. N‐doped Ni3S2nanosheets achieve a fairly low overpotential of 155 mV at 10 mA cm−2and an excellent exchange current density of 0.42 mA cm−2in 1.0
m KOH electrolyte. The mass activity of 16.9 mA mg−1and turnover frequency of 2.4 s−1obtained at 155 mV are significantly higher than the values reported for other Ni3S2‐based HER catalysts, and comparable to the performance of best HER catalysts in alkaline medium. These experimental data together with theoretical analysis suggest that the outstanding catalytic activity of N‐doped Ni3S2is due to the enriched active sites with favorable H adsorption free energy. The activity in the Ni3S2is highly correlated with the coordination number of the surface S atoms and the charge depletion of neighbor Ni atoms. These new findings provide important guidance for future experimental design and synthesis of optimal HER catalysts. -
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Abstract Abundant transition metal borides are emerging as substitute electrochemical hydrogen evolution reaction (HER) catalysts for noble metals. Herein, an unusual canonic‐like behavior of the
c lattice parameter in the AlB2‐type solid solution Cr1–x Mox B2(x = 0, 0.25, 0.4, 0.5, 0.6, 0.75, 1) and its direct correlation to the HER activity in 0.5 M H2SO4solution are reported. The activity increases with increasingx , reaching its maximum atx = 0.6 before decreasing again. At high current densities, Cr0.4Mo0.6B2outperforms Pt/C, as it needs 180 mV less overpotential to drive an 800 mA cm−2current density. Cr0.4Mo0.6B2has excellent long‐term stability and durability showing no significant activity loss after 5000 cycles and 25 h of operation in acid. First‐principles calculations have correctly reproduced the nonlinear dependence of thec lattice parameter and have shown that the mixed metal/B layers, such as (110), promote hydrogen evolution more efficiently forx = 0.6, supporting the experimental results. -
null (Ed.)This paper reports a highly active and stable nonprecious metal electrocatalyst based on bimetallic nanoscale nickel molybdenum nitride developed for the hydrogen evolution reaction (HER). A composite of 7 nm Ni 2 Mo 3 N nanoparticles grown on nickel foam (Ni 2 Mo 3 N/NF) was prepared through a simple and economical synthetic method involving one-step annealing of Ni foam, MoCl 5 , and urea without a Ni precursor. The Ni 2 Mo 3 N/NF exhibits high activity with low overpotential ( η 10 of 21.3 mV and η 100 of 123.8 mV) and excellent stability for the HER, achieving one of the best performances among state-of-the-art transition metal nitride based catalysts in alkaline media. Supporting density functional theory (DFT) calculations indicate that N sites in Ni 2 Mo 3 N with a N–Mo coordination number of four have a hydrogen adsorption energy close to that of Pt and hence may be responsible for the enhanced HER performance.more » « less
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Abstract The development of non‐noble metal materials for efficient hydrogen evolution reaction (HER) in wide pH range is still a challenge at present. Herein, a predesigned polyoxometalate (POM)‐based metal–organic polymer {L3Co2 · 6H2O}[H3GeMo12O40] · 9H2O (L = 1,2,4‐triazole) is employed as bimetallic source together with thiourea converting to CoS2@MoS2on carbon cloth (CC) (abbreviated to CoS2@MoS2@CC) for the first time. Impressively, the CoS2@MoS2in the form of vertically interconnected nanoarrays with multiple interfaces are grown in situ on CC and act as electrodes directly for HER. The CoS2@MoS2@CC‐30h composite exhibits superb activity and long‐durability in both acidic and alkaline media. Low overpotential is achieved in 0.5
m H2SO4(65 mV) and 1.0m KOH (87 mV) for 10 mA cm−2versus RHE, which overmatch major MoS2‐/POM‐based electrocatalysts. This work therefore may shed substantial lights on designing active and durable molybdenum‐based bi‐/polymetallic sulfide from variable POM‐based metal–organic polymers for electrocatalytic hydrogen evolution reaction in wide pH range.
