| 1. |
- Oliveira, Filipa M., et al.
(author)
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Alkaline water electrolysis performance of mixed cation metal phosphorous trichalcogenides
- 2024
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In: Materials Today Energy. - 2468-6069. ; 39
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Journal article (peer-reviewed)abstract
- A variety of mixed-cation metal phosphorus trichalcogenides (MnNiP2S6, FeCoP2S6, FeNiP2S6, CoNiP2S6, FeCoNiP2S6, and the high-entropy CrMnFeNiCoZnP2S6) are synthesized using chemical vapor transport and tested for water splitting under alkaline conditions. Among the materials synthesized, FeCoP2S6 demonstrates the most promising performance, acting as a catalyst with an overpotential of 409 mV and 325 mV for the hydrogen evolution reaction and oxygen evolution reaction (OER), respectively. To further enhance its catalytic activity, a combination of liquid-phase exfoliation techniques assisted by microwave and sonication is employed to FeCoP2S6 (exf-FeCoP2S6), thereby increasing the surface area and exposing more active sites. Promising results are obtained for the OER, with exf-FeCoP2S6 displaying an overpotential of 271 mV, a value very closely matching the best performances reported in the literature under alkaline conditions. Long-term stability tests show a stable profile over time, corroborated by the XPS analysis and computer modeling, which confirms minimal degradation of the catalyst.
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| 2. |
- Rafei, Mouna, et al.
(author)
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Hydrogen evolution mediated by sulfur vacancies and substitutional Mn in few-layered molybdenum disulfide
- 2024
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In: Materials Today Energy. - : Elsevier. - 2468-6069. ; 41
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Journal article (peer-reviewed)abstract
- MoS2 is widely praised as a promising replacement for Pt as an electrocatalyst for the hydrogen evolution reaction (HER), but even today, it still suffers from low performance. This issue is tackled by using Mn3+ as a surface modifier to trigger sulfur vacancy formation and enhance electron transport in few-layered 2H MoS2. Only 10% of Mn is sufficient to transform the semiconductive MoS2 into an active HER electrocatalyst. The insertion of Mn reduces both HER onset potential and Tafel slope which allows reaching 100 mA/cm2 at an overpotential of 206 mV, ten times larger of what undoped MoS2 can achieve. The enhanced activity arises because Mn3+ introduces electronic states near the conduction band, promotes sulfur vacancies, and increases the hydrogen adsorption. In addition to its facile production and extended shelf-life, Mn–MoS2 exhibits an efficiency of 73% at 800 mA/cm2 and 2.0 V when used in proton exchange membrane water electrolyzers.
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