Single atom catalyst, which contains isolated metal atoms singly dispersed on supports, has great potential for achieving high activity and selectivity in hetero-catalysis and electrocatalysis. ...However, the activity and stability of single atoms and their interaction with support still remains a mystery. Here we show a stable single atomic ruthenium catalyst anchoring on the surface of cobalt iron layered double hydroxides, which possesses a strong electronic coupling between ruthenium and layered double hydroxides. With 0.45 wt.% ruthenium loading, the catalyst exhibits outstanding activity with overpotential 198 mV at the current density of 10 mA cm
and a small Tafel slope of 39 mV dec
for oxygen evolution reaction. By using operando X-ray absorption spectroscopy, it is disclosed that the isolated single atom ruthenium was kept under the oxidation states of 4+ even at high overpotential due to synergetic electron coupling, which endow exceptional electrocatalytic activity and stability simultaneously.
Abstract
Methanol is a highly desirable product of CO
2
electroreduction due to its wide array of industrial applications. However, the development of CO
2
-to-methanol electrocatalysts with high ...performance is still challenging. Here we report an operationally simple in situ dual doping strategy to construct efficient CO
2
-to-methanol electrocatalysts. In particular, when using Ag,S-Cu
2
O/Cu as electrocatalyst, the methanol Faradaic efficiency (FE) could reach 67.4% with a current density as high as 122.7 mA cm
−2
in an H-type cell using 1-butyl-3-methylimidazolium tetrafluoroborate/H
2
O as the electrolyte, while the current density was below 50 mA cm
−2
when the FE was greater than 50% over the reported catalysts. Experimental and theoretical studies suggest that the anion S can effectively adjust the electronic structure and morphology of the catalysts in favor of the methanol pathway, whereas the cation Ag suppresses the hydrogen evolution reaction. Their synergistic interactions with host material enhance the selectivity and current density for methanol formation. This work opens a way for designing efficient catalysts for CO
2
electroreduction to methanol.
Hydrogen evolution reaction (HER) has prospect to becoming clean and renewable technology for hydrogen production and Ni–Mo alloy is among the best HER catalysts in alkaline electrolytes. Here, an in ...situ topotactic reduction method to synthesize ultrathin 2D Ni–Mo alloy nanosheets for electrocatalytic hydrogen evolution is reported. Due to its ultrathin structure and tailored composition, the as‐synthesized Ni–Mo alloy shows an overpotential of 35 mV to reach a current density of 10 mA cm−2, along with a Tafel slope of 45 mV decade−1, demonstrating a comparable intrinsic activity to state‐of‐art commercial Pt/C catalyst. Besides, the vertically aligned assemble structure of the 2D NiMo nanosheets on conductive substrate makes the electrode “superaerophobic,” thus leading to much faster bubble releasing during HER process and therefore shows faster mass transfer behavior at high current density as compared with drop drying Pt/C catalyst on the same substrate. Such in situ topotactic conversion finds a way to design and fabricate low‐cost, earth‐abundant non‐noble metal based ultrathin 2D nanostructures for electrocatalytic issues.
An ultrathin Ni–Mo alloy nanosheet array is synthesized through an in situ topotactic reduction method. Attributing to the ultrathin 2D morphology, tailored alloy composition, and superaerophobic assembled structure, the Ni–Mo alloy nanosheets show faster electron transport and mass transfer toward hydrogen evolution reaction, which are even better than state‐of‐art Pt/C catalyst.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Simultaneously synthesizing and structuring atomically thick or ultrathin 2D non‐precious metal nanocrystal may offer a new class of materials to replace the state‐of‐art noble‐metal ...electrocatalysts; however, the synthetic strategy is the bottleneck which should be urgently solved. Here we report the synthesis of an ultrathin nickel nanosheet array (Ni‐NSA) through in situ topotactic reduction from Ni(OH)2 array precursors. The Ni nanosheets showed a single‐crystalline lamellar structure with only ten atomic layers in thickness and an exposed (111) facet. Combined with a superaerophobic (low bubble adhesive) arrayed structure the Ni‐NSAs exhibited a dramatic enhancement on both activity and stability towards the hydrazine‐oxidation reaction (HzOR) relative to platinum. Furthermore, the partial oxidization of Ni‐NSAs in ambient atmosphere resulted in effective water‐splitting electrocatalysts for the hydrogen‐evolution reaction (HER).
Low‐cost electrocatalysts: Ultrathin nickel nanosheets were synthesized by gently reducing a Ni(OH)2 nanosheet array on a metal substrate (see picture). The electrocatalytic performance of the Ni nanosheets was tested on the oxidation of hydrazine and the hydrogen‐evolution reaction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
High-rate electrolysis of CO
2
to C
2+
alcohols is of particular interest, but the performance remains far from the desired values to be economically feasible. Coupling gas diffusion ...electrode (GDE) and 3D nanostructured catalysts may improve the efficiency in a flow cell of CO
2
electrolysis. Herein, we propose a route to prepare 3D Cu-chitosan (CS)-GDL electrode. The CS acts as a “transition layer” between Cu catalyst and the GDL. The highly interconnected network induces growth of 3D Cu film, and the as-prepared integrated structure facilitates rapid electrons transport and mitigates mass diffusion limitations in the electrolysis. At optimum conditions, the C
2+
Faradaic efficiency (FE) can reach 88.2% with a current density (geometrically normalized) as high as 900 mA cm
−2
at the potential of −0.87 V vs. reversible hydrogen electrode (RHE), of which the C
2+
alcohols selectivity is 51.4% with a partial current density of 462.6 mA cm
−2
, which is very efficient for C
2+
alcohols production. Experimental and theoretical study indicates that CS induces growth of 3D hexagonal prismatic Cu microrods with abundant Cu (111)/Cu (200) crystal faces, which are favorable for the alcohol pathway. Our work represents a novel example to design efficient GDEs for electrocatalytic CO
2
reduction (CO
2
RR).
Summary
CRISPR/Cas‐based (clustered regularly interspaced short palindromic repeats/CRISPR‐associated) screening has been proved to be an efficient method to study functional genomics from yeast to ...human. In this study, we report the development of a focused CRISPR/Cas‐based gene activation library in Saccharomyces cerevisiae and its application in gene identification based on functional screening towards improved thermotolerance. The gene activation library was subjected to screening at 42°C, and the same library cultured at 30°C was set as a control group. After five successive subcultures, five clones were randomly picked from the libraries cultured at 30 and 42°C, respectively. The five clones selected at 30°C contain the specificity sequences of five different single guide RNAs, whereas all the five clones selected at 42°C contain the specificity sequence of one sgRNA that targets the promoter region of OLE1. A crucial role of OLE1 in thermotolerance was identified: the overexpression of OLE1 increased fatty acid unsaturation, and thereby helped counter lipid peroxidation caused by heat stress, rendering the yeast thermotolerant. This study described the application of CRISPR/Cas‐based gene activation screening with an example of thermotolerant yeast screening, demonstrating that this method can be used to identify functional genes in yeast.
In this study, we report the development of a focused CRISPR/Cas‐based gene activation library in Saccharomyces cerevisiae and its application in gene identification based on functional screening towards improved thermotolerance. A crucial role of OLE1 in thermotolerance was identified: the overexpression of OLE1 increased fatty acid unsaturation, and thereby helped counter lipid peroxidation caused by heat stress, rendering the yeast thermotolerant.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
•Ethanol yields of SFA1OE were around 0.492 g/g totalsugars in different hydrolysates.•Diploid strain SQ-2 displays improved ethanol yield and high temperature resistance.•Contributions of gene SFA1 ...on ethanol yields were evaluated in various hydrolysates.•SFA1OE with high ethanol yield fits to alkaline-distilled sweet sorghum bagasse.
Here, an engineered Saccharomyces cerevisiae strain SFA1OE was constructed by overexpressing SFA1 in a reported WXY70 with effective six-gene clusters. Under simulated maize hydrolysate, SFA1OE produced an ethanol yield of 0.492 g/g totalsugars within 48 h. The productivity of SFA1OE was comprehensively evaluated in typical hydrolysates from stalks of maize, sweet sorghum, wheat and Miscanthus. Within 48 h, SFA1OE achieved an ethanol yield of 0.489 g/g totalsugars in the optimized hydrolysate of alkaline-distilled sweet sorghum bagasse derived from Advanced Solid-State Fermentation process. By crossing SFA1OE with a DQ1-derived haploid strain, we obtained an evolved diploid strain SQ-2, exhibiting improved ethanol production and thermotolerance. This study demonstrates that overexpressing SFA1 enables efficient fermentation performance in different lignocellulosic hydrolysates, especially in the hydrolysate of alkaline-distilled sweet sorghum bagasse. The increased cellulosic bioethanol production of SFA1OE provides a promising platform for efficient biorefineries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Biological treatment of high salinity organic wastewater is a significant challenge because many microorganisms involved in the anaerobic digestion process cannot survive high osmotic pressures. In ...order to alleviate some of the stresses associated with the treatment of high salinity wastewater, two lab-scale up-flow anaerobic sludge bed reactors with or without magnetite (100 g/L) were used to treat high salinity organic wastewater. This study showed that the bioreactor amended with magnetite had higher chemical oxygen demand removal efficiencies (90.2% ± 0.54% vs 73.1% ± 1.9%) and methane production rates (4082 ± 334 ml (standard temperature and atmospheric pressure, STP)/d vs 2640 ± 120 ml (STP)/d) than the non-amended control reactor. In addition, the consumption of volatile fatty acids (20.9 ± 3.4 mM vs 61.7 ± 2.0 mM) was accelerated. Microbial community analysis revealed that the addition of magnetite caused the enrichment of many bacterial genera known to form robust biofilms (i.e. Pseudomonas) that are also capable of extracellular electron transfer and methanogens from the genus Methanosarcina which have been shown to participate in direct interspecies electron transfer. These results show that magnetite addition could enhance the performance of anaerobic digesters treating high salinity wastewater.
•Incorporation of magnetite enhances methanogenic treatment efficiency of HSOW.•Bacteria capable of extracellular electron transfer were enriched in HSOW.•Methanosarcina species contributed to the enhanced performance of magnetite reactor.•Bioreactors amended with magnetite had increased methane production rates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Density gradient ultracentrifugation (DGUC) is an effective separation and purification technique of nanoparticles. Introducing a reaction zone or an assembly zone in the gradient can find the ...surface reaction and assembly mechanism of NPs since the reaction time can be precisely controlled and the chemical environment change can be extremely fast. The ultraconcentration of NPs can also be achieved by introducing the water/oil interfaces into the separation chamber. In this review, we have emphasized the conceptual advances in classification, mechanism of DGUC and synthesis-structure-property relationships of NPs to provide the significant clue for the further synthesis optimization.
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In this article, we review the advancement in nanoseparation and concomitant purification of nanoparticles (NPs) by using density gradient ultracentrifugation technique (DGUC) and demonstrated by taking several typical examples. Study emphasizes the conceptual advances in classification, mechanism of DGUC and synthesis-structure-property relationships of NPs to provide the significant clue for the further synthesis optimization. Separation, concentration, and purification of NPs by DGUC can be achieved at the same time by introducing the water/oil interfaces into the separation chamber. We can develop an efficient method “lab in a tube” by introducing a reaction zone or an assembly zone in the gradient to find the surface reaction and assembly mechanism of NPs since the reaction time can be precisely controlled and the chemical environment change can be extremely fast. Finally, to achieve the best separation parameters for the colloidal systems, we gave the mathematical descriptions and computational optimized models as a new direction for making practicable and predictable DGUC separation method. Thus, it can be helpful for an efficient separation as well as for the synthesis optimization, assembly and surface reactions as a potential cornerstone for the future development in the nanotechnology and this review can be served as a plethora of advanced notes on the DGUC separation method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Seawater electrolysis offers a renewable, scalable, and economic means for green hydrogen production. However, anode corrosion by Cl
pose great challenges for its commercialization. Herein, different ...from conventional catalysts designed to repel Cl
adsorption, we develop an atomic Ir catalyst on cobalt iron layered double hydroxide (Ir/CoFe-LDH) to tailor Cl
adsorption and modulate the electronic structure of the Ir active center, thereby establishing a unique Ir-OH/Cl coordination for alkaline seawater electrolysis. Operando characterizations and theoretical calculations unveil the pivotal role of this coordination state to lower OER activation energy by a factor of 1.93. The Ir/CoFe-LDH exhibits a remarkable oxygen evolution reaction activity (202 mV overpotential and TOF = 7.46 O
s
) in 6 M NaOH+2.8 M NaCl, superior over Cl
-free 6 M NaOH electrolyte (236 mV overpotential and TOF = 1.05 O
s
), with 100% catalytic selectivity and stability at high current densities (400-800 mA cm
) for more than 1,000 h.
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