Regulating Water Reduction Kinetics on MoP Electrocatalysts Through Se Doping for Accelerated Alkaline Hydrogen Production

Owing to its low cost, high conductivity, and chemical stability, Molybdenum phosphide (MoP) has great potential for electrochemically catalyzing the hydrogen evolution reaction (HER). Unfortunately, the development of high-activity MoP still remains a grand challenge in alkali-electrolyzers due to its sluggish water reduction kinetics. Here, we demonstrate a novel strategy for regulating the HER kinetics of the MoP nanowire cathode through partially substituting P atoms with Se dopants. In alkaline solutions, the Se-doped MoP (Se-MoP) nanowire cathode exhibits excellent HER performance with a greatly-decreased overpotential of ∼61 mV at 10 mA cm−2 and a Tafel slope of ∼63 mV dec−1, outperforming currently reported MoP-based electrocatalysts. Experimental and theoretical investigations reveal that Se doping not only facilitates the water dissociation on MoP, but also optimize the hydrogen adsorption free energy, eventually speeding up the sluggish alkaline HER kinetics. Therefore, this work paves a new path for designing MoP-based electrocatalyst with high HER performance in alkaline electrolyzers.

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Regulating Water-Reduction Kinetics in Cobalt Phosphide for Enhancing HER Catalytic Activity in Alkaline Solution

Advanced Materials ◽

10.1002/adma.201606980 ◽

2017 ◽

Vol 29 (28) ◽

pp. 1606980 ◽

Cited By ~ 115

Author(s):

Kun Xu ◽

Hui Ding ◽

Mengxing Zhang ◽

Min Chen ◽

Zikai Hao ◽

...

Keyword(s):

Catalytic Activity ◽

Alkaline Solution ◽

Reduction Kinetics ◽

Water Reduction ◽

Cobalt Phosphide

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Whole Conversion of Soybean Molasses into Isomaltulose and Ethanol by Combining Enzymatic Hydrolysis and Successive Selective Fermentations

Biomolecules ◽

10.3390/biom9080353 ◽

2019 ◽

Vol 9 (8) ◽

pp. 353

Author(s):

Zhi-Peng Wang ◽

Lin-Lin Zhang ◽

Song Liu ◽

Xiao-Yan Liu ◽

Xin-Jun Yu

Keyword(s):

Low Cost ◽

Rhizomucor Miehei ◽

Pichia Stipitis ◽

Raffinose Family Oligosaccharides ◽

Alternative Substrate ◽

Soy Molasses ◽

High Production ◽

Novel Strategy ◽

High Production Cost ◽

High Sucrose

Isomaltulose is mainly produced from sucrose by microbial fermentation, when the utilization of sucrose contributes a high production cost. To achieve a low-cost isomaltulose production, soy molasses was introduced as an alternative substrate. Firstly, α-galactosidase gene from Rhizomucor miehei was expressed in Yarrowia lipolytica, which then showed a galactosidase activity of 121.6 U/mL. Under the effects of the recombinant α-galactosidase, most of the raffinose-family oligosaccharides in soy molasses were hydrolyzed into sucrose. Then the soy molasses hydrolysate with high sucrose content (22.04%, w/w) was supplemented into the medium, with an isomaltulose production of 209.4 g/L, and the yield of 0.95 g/g. Finally, by virtue of the bioremoval process using Pichia stipitis, sugar byproducts in broth were transformed into ethanol at the end of fermentation, thus resulting in high isomaltulose purity (97.8%). The bioprocess employed in this study provides a novel strategy for low-cost and efficient isomaltulose production from soybean molasses.

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Boosting alkaline hydrogen evolution: the dominating role of interior modification in surface electrocatalysis

Energy & Environmental Science ◽

10.1039/d0ee01750g ◽

2020 ◽

Vol 13 (9) ◽

pp. 3110-3118 ◽

Cited By ~ 6

Author(s):

Zhao Li ◽

Wenhan Niu ◽

Zhenzhong Yang ◽

Abdelkader Kara ◽

Qi Wang ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Water Dissociation ◽

Alkaline Solutions ◽

Great Promise ◽

Hydrogen Fuel ◽

Practical Utilization

The alkaline hydrogen evolution reaction (A-HER) holds great promise for clean hydrogen fuel generation but its practical utilization is severely hindered by the sluggish kinetics for water dissociation in alkaline solutions.

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Anomalous hydrogen evolution behavior in high-pH environment induced by locally generated hydronium ions

Nature Communications ◽

10.1038/s41467-019-12773-7 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 36

Author(s):

Xuesi Wang ◽

Chaochen Xu ◽

Mietek Jaroniec ◽

Yao Zheng ◽

Shi-Zhang Qiao

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Adsorption ◽

Water Dissociation ◽

In Situ Raman Spectroscopy ◽

Kinetic Measurements ◽

High Ph ◽

Hydronium Ions ◽

Adsorption Processes ◽

Bulk Model ◽

Evolution Behavior

Abstract Most fundamental studies of electrocatalysis are based on the experimental and simulation results obtained for bulk model materials. Some of these mechanistic understandings are inapplicable for more active nanostructured electrocatalysts. Herein, considering the simplest and most typical electrocatalytic process, the hydrogen evolution reaction, an alternative reaction mechanism is proposed for nanomaterials based on the identification of a new intermediate, which differs from those commonly known for the bulk counterparts. In-situ Raman spectroscopy and electrochemical thermal/kinetic measurements were conducted on a series of nanomaterials under different conditions. In high-pH electrolytes with negligible hydronium (H3O+) concentration in bulk phase, massive H3O+ intermediates are found generating on the catalytic surface during water dissociation and hydrogen adsorption processes. These H3O+ intermediates create a unique acid-like local reaction environment on nanostructured catalytic surfaces and cut the energy barrier of the overall reaction. Such phenomena on nanostructured electrocatalysts explain their widely observed anomalously high activity under high-pH conditions.

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Fabrication of Robust Hydrogen Evolution Reaction Electrocatalyst Using Ag2Se by Vacuum Evaporation

Nanomaterials ◽

10.3390/nano9101460 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1460

Author(s):

Sajjad Hussain ◽

Jinwoong Chae ◽

Kamran Akbar ◽

Dhanasekaran Vikraman ◽

Linh Truong ◽

...

Keyword(s):

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

First Principles ◽

Hydrogen Adsorption ◽

Hydrogen Generation ◽

Low Cost ◽

First Principles Calculations ◽

Electrochemical Surface Area ◽

Complex Catalyst ◽

Catalyst Synthesis

Much research has been done on reliable and low-cost electrocatalysts for hydrogen generation by water splitting. In this study, we synthesized thin films of silver selenide (Ag2Se) using a simple thermal evaporation route and demonstrated their electrocatalytic hydrogen evolution reaction (HER) activity. The Ag2Se catalysts show improved electrochemical surface area and good HER electrocatalytic behavior (367 mV overpotential @ 10 mA·cm−2, exchange current density: ~1.02 × 10−3 mA·cm−2, and Tafel slope: 53 mV·dec−1) in an acidic medium). The reliability was checked in 0.5 M sulfuric acid over 20 h. Our first-principles calculations show the optimal energy of hydrogen adsorption, which is consistent with experimental results. The works could be further extended for finding a new catalyst by associating the selenide, sulfide or telluride-based materials without complex catalyst synthesis procedures.

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An efficient termination control strategy of air-vented dryer for fabric drying

International Journal of Clothing Science and Technology ◽

10.1108/ijcst-07-2017-0097 ◽

2018 ◽

Vol 30 (3) ◽

pp. 412-427 ◽

Cited By ~ 1

Author(s):

Yuhui Wei ◽

Zhaowei Su ◽

Huashan Lu ◽

Xue Mei Ding

Keyword(s):

Energy Consumption ◽

Control Strategy ◽

Low Cost ◽

Drying Time ◽

Content Type ◽

Exhaust Duct ◽

Microscopic Damage ◽

Novel Strategy ◽

Drying Efficiency ◽

Practical Implications

Purpose The purpose of this paper is to develop an efficient termination control strategy of air-vented dryer in term of energy saving, improving smoothness and reducing microscopic damage of fiber. Design/methodology/approach A simple, low cost termination control strategy is developed by testing the instantaneous humidity of exhaust air and then deducing the drying degree of fabric in process. The practicability evaluation of this novel strategy was investigated by using both experimental and mathematical approaches. The effect of termination control strategy on drying efficiency and fabric apparent properties were also discussed. Findings Termination control strategy significantly affects drying time, energy consumption, smoothness and microscopic of fiber. Specially, a novel termination control strategy that the combination of equilibrium moisture content of fabric in ambient environment and relative humidity of exhaust air in exhaust duct is workable and can save 25.2 percent of energy consumption, 26.7 percent of the drying time and improve 0.7 grade of the appearance smoothness, as well as significantly reduce the microscopic damage of fiber compare to the original control strategy of dryer. This indicates possible ways to minimize drying energy consumption and dryer damage by reducing unnecessary migrate out of the water from the clothes. Practical implications The paper is helpful in not only the development of new drying product but also the optimization of appearance smoothness of fabric after drying and reduce the microscopic damage of fiber. Originality/value A novel termination control strategy of dryer is applied to improve drying efficiency of dryer and reduce fabric damage.

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Preparation of N-Doped Carbon Nanosheets from Sewage Sludge for Adsorption Studies of Cr(VI) from Aqueous Solution

Nanomaterials ◽

10.3390/nano9020265 ◽

2019 ◽

Vol 9 (2) ◽

pp. 265 ◽

Cited By ~ 6

Author(s):

Yi Wang ◽

Weinan Zhao ◽

Wanlan Zheng ◽

Shuang Chen ◽

Jinsheng Zhao

Keyword(s):

Sewage Sludge ◽

Porous Carbon ◽

Removal Rate ◽

Low Cost ◽

Waste Water Treatment ◽

Grand Challenge ◽

Koh Activation ◽

Thermal Regeneration ◽

Carbon Nanosheets ◽

Pore Size Distributions

Porous activated carbon with specific morphology and structure are of particular importance for waste water treatment, especially for the adsorption of toxic hexavalent chromium Cr(VI). However, the scalable and cheap production of such absorbents still suffer a grand challenge. Herein, a new type of N-doped nanosheet was innovatively prepared from easily available and low-cost sewage sludge via a facile and recyclable KOH activation method. The N-doped porous carbon nanosheets (N-SAC) produced by introduction of KOH and dicyandiamide, which performed favourable features for metal ions adsorption (93.2% for Cr(VI)) due to its high specific surface area, tuneable pore size distributions and good hydrophilicity. Additionally, the capacity also remained high after two cycles of adsorption by thermal regeneration, with 90.8% removal rate. The DFT calculation also approved that the doping of N could optimize the Mulliken charges distribution and improve the HOMO energy and improve the adsorption ability of N-SAC. This original proposal may inspire new possibility of creating porous carbon absorbents in a recyclable method.

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ITO/Glass as Extended-Gate of FET: A Low-Cost Method for Differential pH-Sensing in Alkaline Solutions

Journal of The Electrochemical Society ◽

10.1149/2.0401912jes ◽

2019 ◽

Vol 166 (12) ◽

pp. B896-B902 ◽

Cited By ~ 3

Author(s):

Naser Mokhtarifar ◽

Frank Goldschmidtboeing ◽

Peter Woias

Keyword(s):

Low Cost ◽

Alkaline Solutions ◽

Ph Sensing ◽

Ito Glass

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Refuting objections to a Global Rural Network (GRNet) for developing nations (originally published in August 2004)

First Monday ◽

10.5210/fm.v0i0.1780 ◽

2007 ◽

Author(s):

Larry Press

Keyword(s):

Rural Areas ◽

High Speed ◽

Low Cost ◽

Developing Nations ◽

Appropriate Technology ◽

Grand Challenge ◽

Sustainable Business ◽

Internet Service ◽

Developing Nation ◽

Internet Connectivity

In a previous article, we suggested that it is now time to undertake a Grand Challenge project: providing Internet connectivity for every village in every developing nation. Doing so would require perhaps a decade and billions of dollars for design and planning, procurement, installation and operation. Critics object that such a project would not be worth the effort and investment. This article considers nine objections to such an undertaking. 1. Internet connectivity would be nice, but it is not a high priority. 2. Internet service has been offered in rural areas of developing nations, and there is little demand for it. 3. There are no applications of interest or value to illiterate rural people who do not speak English. 4. There is no sustainable business model. 5. Developing nations lack the people and resources to do research. 6. Even if the world community can justify sponsoring the research leading to a concrete backbone plan, developing nations cannot afford to implement it. 7. Villagers cannot afford to use the network even if the backbone transport and connection are free. 8. Developing nations cannot afford high–speed connectivity — low–cost store–and–forward technology is more appropriate technology for a poor, developing nation. 9. We should focus on cities where there is already demand, not rural areas. We discuss each of these, and conclude with a brief outline of next steps.

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