Molybdenum sulphides on carbon supports as electrocatalysts for hydrogen evolution in acidic industrial wastewater

Kokko, Marika; Bayerköhler, F.; Erben, Johannes; Zengerle, Roland; Kurz, Philipp; Kerzenmacher, Sven

doi:10.1016/j.apenergy.2016.12.097

Cited by 38 publications

(22 citation statements)

References 53 publications

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“…The technology has received increased attention over past decades [1]. The bioelectrochemical reactions take place in anodic and cathodic components of the MFC have found many potential applications in the fields of wastewater treatment, electricity generation, biogas production, biosensors and bioelectrochemical synthesis [[2], [3], [4], [5], [6], [7], [8], [9], [10]]. Among various carbon sources that have been demonstrated as a fuel in MFCs human urine has proved to be a good substrate due to its high conductivity [11].…”

Section: Introductionmentioning

confidence: 99%

Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective

Pasternak

Greenman

Ieropoulos

2018

Journal of Power Sources

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Appropriate inoculation and maturation may be crucial for shortening the startup time and maximising power output of Microbial Fuel Cells (MFCs), whilst ensuring stable operation. In this study we explore the relationship between electrochemical parameters of MFCs matured under different external resistance (Rext) values (50 Ω - 10 kΩ) using non-synthetic fuel (human urine). Maturing the biofilm under the lower selected Rext results in improved power performance and lowest internal resistance (Rint), whereas using higher Rext results in increased ohmic losses and inferior performance. When the optimal load is applied to the MFCs following maturity, dependence of microbial activity on original Rext values does not change, suggesting an irreversible effect on the biofilm, within the timeframe of the reported experiments. Biofilm microarchitecture is affected by Rext and plays an important role in MFC efficiency. Presence of water channels, EPS and precipitated salts is distinctive for higher Rext and open circuit MFCs. Correlation analysis reveals that the biofilm changes most dynamically in the first 5 weeks of operation and that fixed Rext lefts an electrochemical effect on biofilm performance. Therefore, the initial conditions of the biofilm development can affect its long-term structure, properties and activity.

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Section: Introductionmentioning

confidence: 99%

Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective

Pasternak

Greenman

Ieropoulos

2018

Journal of Power Sources

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“…Tafel slopes were calculated from chronoamperometric "staircase measurements" (see materials and methods) and values of 100 mV dec −1 for MoS 2.6 , 90 mV dec −1 for MoS 3.4 and 160 mV dec −1 for MoS 2 were obtained for the same catalyst loadings. According to these values, the rate limiting step for MoS 2 might be the adsorption of an H atom (the Volmer reaction), while the results for MoS 2.6 and MoS 3.4 do not give clear evidence on the rate limiting step as the values lie between the boundary values of 40 mV dec −1 for the Heyrovsky reaction (reductive desorption) and the Volmer reaction (>120 mV dec −1 ) [13].…”

Section: Electrochemical Characterization Of Mos 2+δ Electrodesmentioning

confidence: 89%

“…Some MoS x electrodes can deliver current densities of 10 mA cm −2 at η~170 mV in 0.5 m H 2 SO 4 . In special applications, for example, acidic industrial wastewaters, these catalysts also show a much better long-term stability than Pt [13]. MoS x materials can be synthesized by solvothermal synthesis [12,14], wet chemical synthesis [5,15], electrodeposition [4,16], thermal decomposition [17] or chemical oxidation [16].…”

Section: Introductionmentioning

confidence: 99%

Structure of Nanocrystalline, Partially Disordered MoS2+δ Derived from HRTEM—An Abundant Material for Efficient HER Catalysis

et al. 2020

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Molybdenum sulfides (MoSx, x > 2) are promising catalysts for the hydrogen evolution reaction (HER) that show high hydrogen evolution rates and potentially represent an abundant alternative to platinum. However, a complete understanding of the structure of the most active variants is still lacking. Nanocrystalline MoS2+δ was prepared by a solvothermal method and immobilized on graphene. The obtained electrodes exhibit stable HER current densities of 3 mA cm−2 at an overpotential of ~200 mV for at least 7 h. A structural analysis of the material by high-resolution transmission electron microscopy (HRTEM) show partially disordered nanocrystals of a size between 5–10 nm. Both X-ray and electron diffraction reveal large fluctuations in lattice spacing, where the average c-axis stacking is increased and the in-plane lattice parameter is locally reduced in comparison to the layered structure of crystalline MoS2. A three-dimensional structural model of MoS2+δ could be derived from the experiments, in which [Mo2S12]2− and [Mo3S13]2− clusters as well as disclinations represent the typical defects in the ideal MoS2 structure. It is suggested that the partially disordered nanostructure leads to a high density of coordinatively modified Mo sites with lower Mo–Mo distances representing the active sites for HER catalysis, and, that these structural features are more important than the S:Mo ratio for the activity.

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“…Another way to promote the activity of MoS 2 is by decreasing the size to increase the edge-to-surface ratio, and in doing so one inevitably ends up in the cluster size regime. Moreover, it has been shown that amorphous MoS x is a more active and stable HER catalyst than crystalline MoS 2 [85]. Modeling amorphous compounds computationally is more difficult, so the precise HER mechanism for MoS x is less well understood.…”

Section: Dichalcogenidesmentioning

confidence: 99%

Few-atom cluster model systems for a hydrogen economy

Vanbuel

Ferrari

Janssens

2020

Advances in Physics: X

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To increase the share of renewable zero-emission energy sources, such as wind and solar power, in our energy supply, the problem of their intermittency needs to be addressed. One way to do so is by buffering excess renewable energy via the production of hydrogen, which can be stored for later use after re-electrification. Such a clean, renewable energy cycle based on hydrogen is commonly referred to as the hydrogen economy. This review deals with cluster model systems of the three main components of the hydrogen economy, i.e. hydrogen generation, hydrogen storage and hydrogen re-electrification, and their basic physical principles. We then present examples of contemporary research on few atom clusters, both in the gas phase and deposited, to show that by studying these clusters as simplified models a mechanistic understanding of the underlying physical and chemical processes can be obtained. Such an understanding will inspire and enable the design of novel materials needed for advancing the hydrogen economy.

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Molybdenum sulphides on carbon supports as electrocatalysts for hydrogen evolution in acidic industrial wastewater

Cited by 38 publications

References 53 publications

Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective

Dynamic evolution of anodic biofilm when maturing under different external resistive loads in microbial fuel cells. Electrochemical perspective

Structure of Nanocrystalline, Partially Disordered MoS2+δ Derived from HRTEM—An Abundant Material for Efficient HER Catalysis

Few-atom cluster model systems for a hydrogen economy

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