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Journal ArticleDOI: 10.1039/D0TA10022F

A bifunctional hexa-filamentous microfibril multimetallic foam: an unconventional high-performance electrode for total water splitting under industrial operation conditions

02 Mar 2021-Journal of Materials Chemistry (The Royal Society of Chemistry)-Vol. 9, Iss: 8, pp 4971-4983
Abstract: Cellulose in various forms possesses high strength, low density, and high aspect ratio with a three-dimensional open network structure, making them ideal candidates as current collectors in energy conversion application. Herein, a surface rough-cellulose-based bamboo fiber with unique and naturally-convoluted morphology is adopted for the fabrication of catalytically active cobalt substrates for water splitting. For the efficient evolution of hydrogen and oxygen, cobalt-based bimetallic alloys, namely, cobalt–molybdenum and cobalt–iron, were electrodeposited. The proposed system possesses a highly macro-porous network of hexa-filament micro-fibrils that demonstrate exceptional catalytic activities. In quantitative terms, the anodic and cathodic current density of 50 and −10 mA cm−2 at respective overpotentials (η) of 250 and 46 mV with a low activation energy (Ea) of 28 kJ mol−1 were achieved. Moreover, when operated under harsh industrial standards of 5 M KOH@343 K, electrodes demonstrate excellent water electrolyzing catalytic activities (η-100(HER) = 147 mV; η100(OER) = 209 mV). This work, thus, promises a new strategy for designing electrode systems that are highly efficient as well as economical as the substrate was obtained from a ubiquitous earth-friendly material for energy conversion application.

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Topics: Water splitting (55%)
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Journal ArticleDOI: 10.1039/D0TA12424A
Sengeni Anantharaj1Institutions (1)
Abstract: Most better performing water splitting electrocatalysts are scarce, and their use increases the cost of production of H2via electrolysis. Among the best performing noble/precious metal electrocatalysts, Ru is most notable because it acts as an excellent electrocatalyst for both oxidation and reduction reactions of water responsible for the H2 production. In fact, Ru outperforms Pt/C as the state-of-the-art water reduction electrocatalyst in alkali. However, the cost-wise more expensive Ru (than Pt and Ir) could not be extensively used in water electrolysis to avoid further increase in the cost of H2 production. Recently, there has been a renewed interest in Ru and is being intensively investigated with various structural and chemical modifications at the nano-level for catalytic water electrolysis with and without other materials. However, there is no comprehensive review that summarizes and analyzes recent developments in water splitting electrocatalysts that are modulated with Ru. Hence, this review is devoted to bringing out the strategies involved in harvesting the best of water splitting electrocatalysts by Ru-tweaking. The same is also benchmarked against their performance at different conditions. Besides, a detailed note on water splitting electrocatalysis and mechanisms involving Ru are given with insights on the phenomena that make it an active interface for water electrolysis.

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Topics: Water splitting (58%), Electrolysis of water (55%), Electrocatalyst (53%) ... show more

12 Citations


Journal ArticleDOI: 10.1016/J.JPOWSOUR.2021.230387
Hongxing Liang1, Min Xu1, Edouard Asselin1Institutions (1)
Abstract: Many studies have investigated the potential to reduce the costs of producing renewable hydrogen via water electrolysis by using nonnoble Fe- and Ni-based catalysts. However, Fe- and Ni-based catalysts corrode in alkaline solutions, which makes it unclear whether the catalytic surface components are the pristine catalysts or their transformation products. Further, corrosion limits the catalyst service life. An understanding of this corrosion process is essential to accurately assess the active catalysts during the oxygen evolution reaction (OER) and to design novel catalysts. This paper reviews the corrosion of five types of monometallic Fe- and Ni-based OER catalysts: pure metals, oxides, (oxy)hydroxides, phosphides, and sulfides. A protocol for a rigorous corrosion characterization method is proposed to avoid misleading results during the design of novel catalysts. In light of the corrosion evolution of these catalysts, several key points are also suggested for consideration during the design of novel monometallic Fe- and Ni-based catalysts with high stability and electroconductivity.

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Topics: Corrosion (55%), Catalysis (51%), Oxygen evolution (51%)

3 Citations


Journal ArticleDOI: 10.1016/J.IJBIOMAC.2021.04.087
Abstract: Over the course of a few decades, the concern of environmental damages of fossil fuels, an increase in CO2 emission and a decrease of hydrogen have been growing more and more. Accordingly, hydrogen production is a crucial issue nowadays. Different polymers are applied to attain the purpose. Among all polymers, biodegradables polymers are the best choices to develop the main aim. Polysaccharides and proteins are biodegradable polymers with unique places and advantages with regards to their ecofriendly properties. There are different techniques to apply and achieve the foremost purpose. It is worthwhile to mention that green and facile methods are always attracting attention in different aspects and fields. The three non-polluting and economical techniques, that is, electrochemical hydrogen evolution reaction (HER), photocatalytic technique, and hydrolysis of hydrides, are reviewed in this paper. This review helps researchers, who are environment supporters, to evaluate and choose the most ecological biopolymers and processes in their work.

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2 Citations



Open accessJournal ArticleDOI: 10.1021/ACS.ENERGYFUELS.1C03475
Qiang Liu1, Fang Zhou1, Yuying Bai1, Weikang Hu1Institutions (1)
30 Nov 2021-Energy & Fuels
Abstract: The issues of carbon corrosion, oxidation, and catalytic stability for most electrocatalysts of oxygen evolution reaction (OER) remain great challenges under high oxidizing environments. Herein, we...

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Topics: Oxygen evolution (60%), Carbon (56%), Oxidizing agent (55%) ... show more
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70 results found


Open accessJournal ArticleDOI: 10.1038/S41467-017-02088-W
Abstract: Many studies have shown how pigments and internal nanostructures generate color in nature. External surface structures can also influence appearance, such as by causing multiple scattering of light (structural absorption) to produce a velvety, super black appearance. Here we show that feathers from five species of birds of paradise (Aves: Paradisaeidae) structurally absorb incident light to produce extremely low-reflectance, super black plumages. Directional reflectance of these feathers (0.05-0.31%) approaches that of man-made ultra-absorbent materials. SEM, nano-CT, and ray-tracing simulations show that super black feathers have titled arrays of highly modified barbules, which cause more multiple scattering, resulting in more structural absorption, than normal black feathers. Super black feathers have an extreme directional reflectance bias and appear darkest when viewed from the distal direction. We hypothesize that structurally absorbing, super black plumage evolved through sensory bias to enhance the perceived brilliance of adjacent color patches during courtship display.

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Topics: Super black (58%), Plumage (51%)

3,488 Citations


Journal ArticleDOI: 10.1021/JA510442P
Abstract: Objective comparisons of electrocatalyst activity and stability using standard methods under identical conditions are necessary to evaluate the viability of existing electrocatalysts for integration into solar-fuel devices as well as to help inform the development of new catalytic systems. Herein, we use a standard protocol as a primary screen for evaluating the activity, short-term (2 h) stability, and electrochemically active surface area (ECSA) of 18 electrocatalysts for the hydrogen evolution reaction (HER) and 26 electrocatalysts for the oxygen evolution reaction (OER) under conditions relevant to an integrated solar water-splitting device in aqueous acidic or alkaline solution. Our primary figure of merit is the overpotential necessary to achieve a magnitude current density of 10 mA cm–2 per geometric area, the approximate current density expected for a 10% efficient solar-to-fuels conversion device under 1 sun illumination. The specific activity per ECSA of each material is also reported. Among HER...

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Topics: Overpotential (55%), Electrocatalyst (52%)

2,231 Citations


Open accessJournal ArticleDOI: 10.1038/S41467-018-04768-7
Zhen Liu1, Zongyang Lu2, Guang Yang2, Shisheng Huang2  +10 moreInstitutions (2)
Abstract: A recently developed adenine base editor (ABE) efficiently converts A to G and is potentially useful for clinical applications. However, its precision and efficiency in vivo remains to be addressed. Here we achieve A-to-G conversion in vivo at frequencies up to 100% by microinjection of ABE mRNA together with sgRNAs. We then generate mouse models harboring clinically relevant mutations at Ar and Hoxd13, which recapitulates respective clinical defects. Furthermore, we achieve both C-to-T and A-to-G base editing by using a combination of ABE and SaBE3, thus creating mouse model harboring multiple mutations. We also demonstrate the specificity of ABE by deep sequencing and whole-genome sequencing (WGS). Taken together, ABE is highly efficient and precise in vivo, making it feasible to model and potentially cure relevant genetic diseases. CRISPR-based base editors allow for single nucleotide genome editing in a range of organisms. Here the authors demonstrate the in vivo generation of mouse models carrying clinically relevant mutations using C→T and A→G editors.

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Topics: Genome editing (52%)

2,094 Citations


Journal ArticleDOI: 10.1021/JA503372R
Abstract: In this Communication, we report the topotactic fabrication of self-supported nanoporous cobalt phosphide nanowire arrays on carbon cloth (CoP/CC) via low-temperature phosphidation of the corresponding Co(OH)F/CC precursor. The CoP/CC, as a robust integrated 3D hydrogen-evolving cathode, shows a low onset overpotential of 38 mV and a small Tafel slope of 51 mV dec–1, and it maintains its catalytic activity for at least 80 000 s in acidic media. It needs overpotentials (η) of 67, 100, and 204 mV to attain current densities of 10, 20, and 100 mA cm–2, respectively. Additionally, this electrode offers excellent catalytic performance and durability under neutral and basic conditions.

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Topics: Nanoporous (54%), Overpotential (53%), Tafel equation (52%) ... show more

1,798 Citations


Open accessJournal ArticleDOI: 10.1021/JA405351S
Abstract: A detailed investigation has been carried out of the structure and electrochemical activity of electrodeposited Ni-Fe films for the oxygen evolution reaction (OER) in alkaline electrolytes. Ni-Fe films with a bulk and surface composition of 40% Fe exhibit OER activities that are roughly 2 orders of magnitude higher than that of a freshly deposited Ni film and about 3 orders of magnitude higher than that of an Fe film. The freshly deposited Ni film increases in activity by as much as 20-fold during exposure to the electrolyte (KOH); however, all films containing Fe are stable as deposited. The oxidation of Ni(OH)2 to NiOOH in Ni films occurs at potentials below the onset of the OER. Incorporation of Fe into the film increases the potential at which Ni(OH)2/NiOOH redox occurs and decreases the average oxidation state of Ni in NiOOH. The Tafel slope (40 mV dec(-1)) and reaction order in OH(-) (1) for the mixed Ni-Fe films (containing up to 95% Fe) are the same as those for aged Ni films. In situ Raman spectra acquired in 0.1 M KOH at OER potentials show two bands characteristic of NiOOH. The relative intensities of these bands vary with Fe content, indicating a change in the local environment of Ni-O. Similar changes in the relative intensities of the bands and an increase in OER activity are observed when pure Ni films are aged. These observations suggest that the OER is catalyzed by Ni in Ni-Fe films and that the presence of Fe alters the redox properties of Ni, causing a positive shift in the potential at which Ni(OH)2/NiOOH redox occurs, a decrease in the average oxidation state of the Ni sites, and a concurrent increase in the activity of Ni cations for the OER.

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1,496 Citations