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•Wood-based Al-air batteries designed for miniaturized power sources.•Photothermal evaporation drives electrolyte flow through porous electrodes.•Integration of 3D wood-based ...microfluidics with solar energy utilization.•Impressive peak power density of 230 mW cm−3.•Stable discharge for over 11 h, ideal for long-lasting power supply.
Capillary microfluidics on porous substrates emerges as an innovative platform for constructing miniaturized electronics. However, maintaining a steady flow within microfluidics remains challenging, thus limiting their practical applications. Inspired by plant transpiration, this work presents a novel wood-based microfluidic Al-air battery (μAAB) configuration driven by a photothermal evaporator (biomimetic “leaf”). Except for the Al anode, the μAAB features an all-wood design, utilizing the well-aligned microchannels of the natural wood for electrolyte transportation, partially charred wood as photothermal evaporator for flow regulating, and wood-derived self-standing carbon cathode for the oxygen reduction reaction. These components are assembled through mortise-and-tenon joints, and the resulting μAAB exhibits a remarkable peak power density of 230 mW cm−3. The superior performance stems from the boosted mass transfer, maximized electrochemical interface and minimized depletion boundary layer provided by the 3D channeled structure of the wood-derived cathode. A steady discharge for over 11 h (200 mA cm−3) is obtained via the continuous electrolyte flow which is facilitated by the photothermal evaporator in the μAAB. This work not only presents a novel concept for miniaturized microfluidic power sources but also highlights the potential of 3D wood-based microfluidics combined with solar energy utilization.
Carbon materials for electrical energy devices, such as battery electrodes or fuel-cell catalysts, require the combination of the contradicting properties of graphitic microstructure and porosity. ...The usage of graphitization catalysts during the synthesis of carbide-derived carbon materials results in materials that combine the required properties, but controlling the microstructure during synthesis remains a challenge. In this work, the controllability of the synthesis route is enhanced by immobilizing the transition-metal graphitization catalyst on a porous carbon shell covering the carbide precursor prior to conversion of the carbide core to carbon. The catalyst loading was varied and the influence on the final material properties was characterized by using physisorption analysis with nitrogen as well as carbon dioxide, X-ray diffraction, temperature-programmed oxidation (TPO), Raman spectroscopy, SEM and TEM. The results showed that this improved route allows one to greatly vary the crystallinity and pore structure of the resulting carbide-derived carbon materials. In this sense, the content of graphitic carbon could be varied from 10-90 wt % as estimated from TPO measurements and resulting in a specific surface area ranging from 1500 to 300 m
·g
.
The main factor constraining the performance of zinc-air batteries (ZABs) is the slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), for which high performance ...electrocatalysts are greatly needed. However, the state-of-the-art oxygen electrocatalysts still suffer from the low activity and limited stability. Herein, we report the synthesis of a novel MnO@Cu-N-C core-shell nanostructure comprising MnO nanorods coated by a Cu-N-C shell that is derived from zeolitic-imidazolate frameworks. The as-prepared MnO@Cu-N-C exhibits fairly high bifunctional electrocatalytic activity toward both ORR and OER, showing a combined overpotential as low as 0.80 V. Both experiments and theoretical calculations indicate that the superior performance is benefited from the synergy between MnO and Cu-N-C, which facilitates the interfacial electron transfer and thus leads to the lower overpotentials. When being employed as the air electrode in the rechargeable ZABs, MnO@Cu-N-C displays a high peak power density of 196.8 mW cm−2 and an impressively prolonged cycle life over 650 h at 10 mA cm−2, outperforming most of recently reported Mn-based counterparts. Moreover, its excellent electrochemical performance can also be transferred to solid-state ZABs, as showcased by a power density of 66.6 mW cm−2 and a cycle life of 16 h at 2 mA cm−2.
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•A novel MnO@Cu-N-C core-shell nanorod featuring a high specific surface area and abundant active sites is designed and constructed.•MnO@Cu-N-C provides satisfactory bifunctional catalytic activity towards ORR and OER reactions.•DFT calculation results suggest that the reduction of the reaction energy barrier is the key to improving ORR/OER activity.•ZAB assembled with the MnO@Cu-N-C catalyst achieves a high peak power density and an excellent cycle life.
Ionic liquids in electrocatalysis Zhang, Gui-Rong; Etzold, Bastian J.M.
Journal of energy chemistry,
March 2016, 2016-03-00, 20160301, Letnik:
25, Številka:
2
Journal Article
Recenzirano
The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent ...structure of active sites but also by the properties of the interfacial structures at catalytic surfaces. Ionic liquids (ILs), as a unique class of metal salts with melting point below 100°C, present themselves as ideal modulators for manipulations of the interfacial structures. Due to their excellent properties such as good chemical stability, high ionic conductivity, wide electrochemical windows and tunable solvent properties the performance of electrocatalysts can be substantially improved through ILs. In the current minireview, we highlight the critical role of the IL phase at the microenvironments created by the IL, the liquid electrolyte, catalytic nanoparticles and/or support materials, by detailing the promotional effect of IL in electrocatalysis as reaction media, binders, and surface modifiers. Updated exemplary applications of IL in electrocatalysis are given and moreover, the latest developments of IL modified electrocatalysts following the “Solid Catalyst with Ionic Liquid Layer (SCILL)” concept are presented.
Ionic liquids, as versatile molecules with numerous unique properties, have shown great promise to boost the performance of electrocatalytic systems. Display omitted
Objective Nonalcoholic fatty liver disease (NAFLD) is a condition associated with type 2 diabetes (T2D). Insulin resistance, a common pathogenesis of NAFLD and T2D, is partially caused by alterations ...in angiotensin II (Ang II) and is accompanied by hypoadiponectinemia. We aimed to investigate whether the circulating Ang II and adiponectin concentrations are related to hyperglycemia in male NAFLD patients. Methods Thirty-five controls and 85 NAFLD patients without prior known T2D were enrolled. All participants were non-smoking men who performed 75-g oral glucose tolerance tests. According to the American Diabetes Association (ADA) criteria, the NAFLD patients were divided into the euglycemia and hyperglycemia groups. The NAFLD patients with hyperglycemia were further divided into the isolated impaired fasting glucose (I-IFG) and postprandial hyperglycemia subgroups. The fasting serum Ang II and adiponectin concentrations were measured. Results Among the 85 NAFLD patients, 40 (47%) had hyperglycemia, including I-IFG (18%) and postprandial hyperglycemia (29%). The serum Ang II concentrations in the euglycemia and hyperglycemia groups were significantly higher than those observed in the control and euglycemia groups, respectively; whereas the serum adiponectin concentrations were significantly lower. The serum Ang II concentrations were significantly higher in the postprandial hyperglycemia subgroup than in the I-IFG subgroup. The serum Ang II and adiponectin concentrations were found to be independent predictors of hyperglycemia in the NAFLD patients. The serum Ang II concentration was significantly associated with the serum adiponectin and 2-hour postprandial glucose concentrations in the NAFLD patients. Conclusion An increased circulating Ang II concentration is associated with hypoadiponectinemia and postprandial hyperglycemia in male NAFLD patients and may be involved in the pathogenesis of T2D in NAFLD patients.
Non-precious metal catalysts show great promise to replace the state-of-the-art Pt-based catalysts for catalyzing the oxygen reduction reaction (ORR), while their catalytic activity still needs to be ...greatly improved before their broad-based application. Here, we report a facile approach to improving the performance of zeolitic imidazolate framework-derived carbon (ZDC) toward the ORR by incorporating a small amount of ionic liquid (IL). The IL would preferentially fill the micropores of ZDC and greatly enhance the utilization of the active sites within the micropores, which are initially not accessible due to insufficient surface wetting. It is also disclosed that the ORR activity in terms of kinetic current at 0.85 V depends on the loading amount of the IL, and the maximum activity is obtained at a mass ratio of IL to ZDC at 1.2. The optimum stems from the counterbalance between the enhanced utilization of the active sites within the micropores and the retarded diffusion of the reactants within the IL phase due to its high viscosity.
Phenol was synthesized through directly hydroxylation reaction of benzene over VO
x
/CuSBA-15 catalyst using molecular dioxygen as an oxidant in the presence of ascorbic acid. A high yield of phenol ...was achieved at ca. 27% with the selectivity of nearly 100%.
▪
The vanadium and copper oxide species supported catalyst, VO
x
/CuSBA-15, was synthesized to catalyze the hydroxylation reaction of benzene to form phenol using molecular dioxygen in the presence of ascorbic acid. A high yield of phenol was achieved at ca. 27% with the selectivity of nearly 100%. The VO
x
/CuSBA-15 has two characteristics that it can selectively activate dioxygen molecules rather than H
2O
2, and it can selectively catalyze benzene hydroxylation to form phenol, but can hardly catalyze phenol for further oxidation under the same reaction conditions. Both copper and vanadium oxide species supported on a mesoporous silicate has a prominent catalytic performance toward the benzene hydroxylation reaction comparing to the other bi-transition metal oxides or monometallic catalysts on the same support. The results suggest that there might be a synergy between copper and vanadium oxide species on the support. It is believed that benzene hydroxylation over the VO
x
/CuSBA-15 catalyst occurs through the hydroxyl radical pathway, and the catalytic activation of molecular oxygen to form hydroxyl radical would be a rate determining step.
Abstract Varicocele, a cause of male infertility, occurs in nearly 40% of infertile males. It has been postulated that varicoceles may cause sperm DNA damage. Sperm DNA integrity has been recognized ...as one of the important determinants of normal fertilization and embryo growth in natural and assisted conception. Eighty-three human studies were identified after an extensive literature search involving the role of varicoceles in sperm DNA damage. Of the 83 studies, 12 were selected that measured similar types of reactive sperm DNA damage. Seven studies determined the damage of sperm DNA in varicocele-associated patients and six studies evaluated the efficacy of varicocelectomy. One study was a duplicate because both outcomes were included. Data were analysed using RevMan software. The overall estimate showed that patients with varicoceles have significantly higher sperm DNA damage than controls, with a mean difference of 9.84% (95% CI 9.19 to 10.49; P < 0.00001). A varicocelectomy can improve sperm DNA integrity, with a mean difference of −3.37% (95% CI −4.09 to −2.65; P < 0.00001). In conclusion, there is increased sperm DNA damage in patients with varicoceles and varicocelectomy may be a possible treatment; however, more studies with appropriate controls are needed to confirm this finding. A varicocele is an important cause of male infertility and occurs in nearly 40% of infertile males. The recent understanding of the effect of varicoceles in male reproduction has led some researchers to postulate varicoceles as the possible cause of sperm DNA damage. Eighty-three human studies were identified after an extensive literature search involving the role of varicoceles in sperm DNA damage. Of the 83 studies, 12 were selected that measured similar types of reactive sperm DNA damage by a similar method. Seven studies determined the damage of sperm DNA in varicocele-associated patients and six studies evaluated the efficacy of varicocelectomy. One study was a duplicate because both outcomes were included. The data were then entered in the RevMan software for analysis. The overall estimate showed that patients with varicoceles have significantly higher sperm DNA damage than controls, with a mean difference of 9.84% (95% CI 9.19 to 10.49; P < 0.00001). A varicocelectomy can improve sperm DNA integrity, with a mean difference of −3.37% (95% CI −4.09 to −2.65; P < 0.00001). Based on the results, it can be concluded that there is increased sperm DNA damage in patients with varicoceles and that varicocelectomy may be a possible treatment; however, more studies with appropriate controls are needed to confirm this finding.
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