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The selective and efficient electrocatalytic transformation of carbon dioxide (CO2) to multicarbon alcohols (e.g., C2H5OH and C3H7OH) is a challenge in renewable and sustainable energy research. Herein, a series of hybrid catalysts consisting of Cu nanoparticles supported on N-doped porous carbon (Cu/NPC) were prepared. It was demonstrated that the selectivity for C2H5OH or C3H7OH could be tuned by introducing N-doped porous carbon materials as cocatalysts with different pyridinic N contents, which could in situ produce a reactive CO intermediate from CO2. By varying the pyridinic N content, highly selective production of multicarbon alcohols was achieved using the Cu/NPC hybrid catalysts with a high faradaic efficiency for one pot production of multicarbon alcohols up to 73.3% at −1.05 V (vs. RHE). The faradaic efficiency for C2H5OH and C3H7OH was 64.6% and 8.7%, respectively. The pyridinic N species were likely the CO-producing sites and together with Cu catalytic sites acted cooperatively to produce C2H5OH and C3H7OH via a two-site mechanism for efficient CO2 reduction to multicarbon alcohols. These findings provide novel guidance for the rational design of electrocatalysts and for tuning the catalytic activity and selectivity for multicarbon alcohol production from CO2. [ABSTRACT FROM AUTHOR]

We developed a new and efficient sulfur-tolerant catalyst for application as a solid oxide electrolysis cell (SOEC) cathode designed with in situ exsolved CoNi alloy nanoparticles anchored on a Ruddlesden–Popper (R.P.) support of La1.2Sr0.8Co0.4Mn0.6O4 and evaluated its catalytic activity for CO2 electrolysis to CO under a CO2 gas stream containing H2S species. This catalyst was prepared by in situ annealing of a perovskite derivative (La0.6Sr0.4Co0.5Ni0.2Mn0.3O3) in a 20% H2/N2 gas at 800 °C. The catalyst exhibited good reversibility of structural transitions during reduction and re-oxidation processes. A high current density of 703 mA cm−2 was achieved at 1.3 V and 850 °C with a maximum faradaic efficiency of 97.8%. In situ grown CoNi alloy nanoparticles and the high oxygen vacancy content in the R.P. support were responsible for its high catalytic activity and efficiency. Importantly, no sign of performance degradation was observed in galvanostatic tests over a period of 90 h operation under H2S-containing CO2 gas conditions. Moreover, the catalyst showed no noticeable structural changes even after exposure to 100 ppm H2S/N2, indicating that the catalyst developed in this study is highly active for CO2 electrolysis with a high tolerance against sulfur-poisoning species. Therefore, this Ruddlesden–Popper material with in situ exsolved CoNi alloy nanoparticles should be a promising cathode catalyst for practical application to H2S-containing CO2 gas streams that are effluents of power stations or steel making plants. [ABSTRACT FROM AUTHOR]

This report demonstrates the modification of reduced graphene oxide (RGO) nanosheets by decorating SnO2 nanorod bundles and nanoparticles on the surface for effective use of the graphene as supercapacitor electrode materials. The shape‐ and density‐controlled SnO2 nanostructures were prepared through hydrothermal synthesis and acted as spacer materials to physically inhibit the overlapping of the RGO sheets; this is known as the restacking effect. When measuring the electrochemical properties, the electrode comprising RGO with SnO2 nanorod bundles (RGO−SnO2−NR) revealed a higher capacitance, rate capability, and cyclic stability than the RGO electrode with SnO2 nanoparticles (RGO−SnO2−NP) and the bare RGO electrode, indicating the effective role of the surface‐implanted SnO2 spacer during the electrode reactions of the double‐layer capacitor. The electrochemical superiority of RGO−SnO2−NR could be explained by the fact that wedge‐like SnO2 nanorod bundles between the RGO sheets promote fast transfer and approach of electroactive species to form the electrochemical double layer at the electrode surface. Moreover, the improved mass transfer behavior of the RGO−SnO2 composite electrodes and the role of the SnO2 nanostructures were reasonably verified by various electrochemical analyses. [ABSTRACT FROM AUTHOR]

Current lithium‐ion batteries have a low theoretical capacity that is insufficient for use in emerging electric vehicles and energy‐storage systems. The development of lithium‐sulfur batteries utilizing Li2S cathodes would be a promising option to overcome the capacity limitation. In this work, new three‐dimensional (3D) honeycomb‐like N‐doped carbon nanowebs (HCNs) have been synthesized through a facile aqueous solution route for use as a cathode material in lithium‐sulfur batteries. The Li2S@HCNs cathode delivers a high discharge capacity of approximately 815 mAh g−1 after 65 cycles at 0.1 C, along with a superior rate capacity of approximately 568 mAh g−1 even at 2 C. The outstanding electrochemical rate performance is ascribed to their unique 3D honeycomb‐like nanoweb structure, consisting of nanowires derived from polypyrrole. These properties greatly enhance the electrochemical reaction kinetics by providing efficient electron pathways and hollow channels for electrolyte transport. Nitrogen doping in the carbon nanowebs also considerably improves the chemisorption properties by tuning affinity between sulfur and oxygen functional groups on the carbon framework. The simple synthesis strategy and the resulting unique electrode structure could present a new avenue in nanostructure research for high‐performance lithium‐sulfur batteries. Electrifying nanowebs: Three‐dimensionally interconnected carbon‐nanowire composites are demonstrated as electrode for use in the lithium‐sulfur battery, and the electrochemical properties are investigated with Li2S. These electrodes can provide efficient pathways for charge transport and promote diffusion of the liquid electrolyte for the enhanced electrochemical reaction kinetics. [ABSTRACT FROM AUTHOR]

Abstract: A designed electrode material of carbon‐encapsulated tin dioxide core–shell nanowires that are synthesized directly on reduced graphene oxide substrates is reported, and its application as a positive electrode material for lithium‐ion battery is shown. Each of the individual tin dioxide nanowires is wrapped with carbon shell layers and grown on a reduced graphene oxide substrate, which gives rise to structural benefits for electrochemical performance of the lithium‐ion battery. Such carbon structures allow the electrode materials to withstand the mechanical stress during repeated charge/discharge processes and facilitate the reaction kinetics for the lithiation/delithiation processes. In the electrochemical cell tests, the synergetic effect of the proposed electrode design is explicitly verified by presenting highly enhanced rate capability and cycle durability on full‐cell batteries as well as half‐cell tests. [ABSTRACT FROM AUTHOR]

In this paper, α-Fe2O3 hollow spheres in different sizes were successfully synthesized through a glycerol emulsion template method for use as efficient electrode materials in lithium-ion batteries. The sizes of α-Fe2O3 hollow sphere could be easily controlled by adjusting the amount of glycerol over the Fe precursor during the hydrothermal synthesis process. A thin carbon layer was subsequently coated on the surface of α-Fe2O3 hollow spheres through hydrothermal treatment with glucose for the carbonization process, in which the carbon phases could serve as a conductive layer for the efficient charge transfer, but also as a buffer layer for the accommodation of volume vibration of the electrode material during cycling. The carbon-coated α-Fe2O3 hollow sphere electrode showed a high discharge capacity of approximately 1452 mAh g−1 with a capacity increase of at least 32 % compared to that of α-Fe2O3 hollow spheres without the carbon coating at the 50th cycle. The stability and cycling performance were also significantly improved by the presence of the carbon layer, indicating that the C/α-Fe2O3 hollow sphere could be a promising metal-oxide anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Current lithium-ion batteries have a low theoretical capacity that is insufficient for use in emerging electric vehicles and energy-storage systems. The development of lithium-sulfur batteries utilizing Li 2 S cathodes would be a promising option to overcome the capacity limitation. In this work, new three-dimensional (3D) honeycomb-like N-doped carbon nanowebs (HCNs) have been synthesized through a facile aqueous solution route for use as a cathode material in lithium-sulfur batteries. The Li 2 S@HCNs cathode delivers a high discharge capacity of approximately 815 mAh g -1 after 65 cycles at 0.1 C, along with a superior rate capacity of approximately 568 mAh g -1 even at 2 C. The outstanding electrochemical rate performance is ascribed to their unique 3D honeycomb-like nanoweb structure, consisting of nanowires derived from polypyrrole. These properties greatly enhance the electrochemical reaction kinetics by providing efficient electron pathways and hollow channels for electrolyte transport. Nitrogen doping in the carbon nanowebs also considerably improves the chemisorption properties by tuning affinity between sulfur and oxygen functional groups on the carbon framework. The simple synthesis strategy and the resulting unique electrode structure could present a new avenue in nanostructure research for high-performance lithium-sulfur batteries., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this paper, bifunctional catalysts consisting of perovskite LaCo 0.8 Fe 0.2 O 3 nanowires (LCFO NWs) with reduced graphene oxide (rGO) sheets were prepared for use in lithium-oxygen (Li-O 2 ) battery cathodes. The prepared LCFO@rGO composite was explored as a cathode catalyst for Li-O 2 batteries, resulting in an outstanding discharge capacity (ca. 7088.2 mAh g -1 ) at the first cycle. Moreover, a high stability of the O 2 -cathode with the LCFO@rGO catalyst was achieved over 56 cycles under the capacity limit of 500 mAh g -1 with a rate of 200 mA g -1 , as compared to the Ketjenblack carbon and LCFO NWs. The enhanced electrochemical performance suggests that these hybrid composites of perovskite LCFO NWs with rGO nanosheets could be a perspective bifunctional catalyst for the cathode oxygen reduction and oxygen evolution reactions in the development of next-generation Li-O 2 battery cathodes.