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Zongping Shao - One of the best experts on this subject based on the ideXlab platform.
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scandium and phosphorus co doped perovskite oxides as high performance Electrocatalysts for the oxygen reduction reaction in an alkaline solution
Journal of Materials Science & Technology, 2020Co-Authors: Meigui Xu, Wei Wang, Yujuan Shen, Wei Zhou, Jun Wang, Zhigang Chen, Zongping ShaoAbstract:Abstract The requirement for a sustainable and renewable energy has inspired substantial interests in designing and developing earth-abundant and high-effectiveness Electrocatalysts/electrodes for fuel cells and metal-air batteries, in which oxygen reduction reaction (ORR) plays a crucial role. Perovskite oxides have acquired rapid attention as ORR Electrocatalysts to replace noble-metal-based catalysts owing to their intrinsic electrocatalytic activity, compositional and structural flexibility. Herein, we report a new Sc and P co-doped perovskite oxide (La0.8Sr0.2Mn0.95Sc0.025P0.025O3-δ, LSMSP) as an active and robust Electrocatalyst for the ORR in an alkaline solution. LSMSP Electrocatalyst shows superior ORR activity and stability than those of pristine La0.8Sr0.2MnO3-δ (LSM), Sc-doped LSM and P-doped LSM due to the optimized average valence of Mn ions, the large surface area, the smaller particle size and the synergetic effect introduced by the co-doping. Moreover, compared to the benchmark Pt/C Electrocatalyst, LSMSP Electrocatalyst displays comparable ORR activity and superior durability. These above results suggest that the co-doping strategy of Sc and P into perovskites is a useful method to design high-performance Electrocatalysts for the ORR, which can be used in other electrocatalysis-based applications.
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spherical ruthenium disulfide sulfur doped graphene composite as an efficient hydrogen evolution Electrocatalyst
ACS Applied Materials & Interfaces, 2018Co-Authors: Jie Yu, Zongping Shao, Wei Zhou, Shuanshuan Miao, Meng NiAbstract:The exploition of cost-efficient and high-performance catalysts to boost hydrogen generation in overall water splitting is crucial to economically obtain green hydrogen energy. Herein, we propose a novel Electrocatalyst consisting of spherical RuS2 on S-doped reduced graphene oxide (s-RuS2/S-rGO) with high catalytic behavior toward hydrogen evolution reaction (HER) in all pH conditions, especially in alkaline electrolytes. RuS2/S-rGO delivers small overpotentials of 25 and 56 mV at current densities of 10 and 50 mA cm–2, respectively, and a low Tafel slope of 29 mV dec–1 with good stability for 100 h in basic solutions. This performance is comparable to and even exceeds that of documented representative Electrocatalysts, including the benchmark Pt/C; since the price of Ru is about 1/25th that of Pt, this novel Electrocatalyst offers a low-cost alternative to Pt-based HER Electrocatalysts. Ruthenium-centered sites of RuS2 in this hybrid catalyst are responsible for the HER active sites, and S doping in RuS...
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srco0 9ti0 1o3 δ as a new Electrocatalyst for the oxygen evolution reaction in alkaline electrolyte with stable performance
ACS Applied Materials & Interfaces, 2015Co-Authors: Chao Su, Yubo Chen, Xiaomin Xu, Guangming Yang, Moses O. Tadé, Zongping ShaoAbstract:The development of efficient, inexpensive, and stable Electrocatalysts for the oxygen evolution reaction (OER) is critical for many electrochemical energy conversion technologies. The prohibitive price and insufficient stability of the state-of-the-art IrO2 Electrocatalyst for the OER inhibits its use in practical devices. Here, SrM0.9Ti0.1O3−δ (M = Co, Fe) perovskites with different B-site transition metal elements were investigated as potentially cheaper OER Electrocatalysts. They were prepared through a typical sol–gel route, and their catalytic activities for the OER in alkaline medium were comparatively studied using rotating disk electrodes. Both materials show high initial intrinsic activities in alkaline electrolyte for the OER, comparable to the benchmark perovskite-type Electrocatalyst Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF), but SrCo0.9Ti0.1O3−δ (SCT) possessed more operational stability than SrFe0.9Ti0.1O3−δ (SFT), even better than BSCF and IrO2 catalysts. Based on the X-ray photoelectron spectra anal...
Sundara Ramaprabhu - One of the best experts on this subject based on the ideXlab platform.
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novel platinum cobalt alloy nanoparticles dispersed on nitrogen doped graphene as a cathode Electrocatalyst for pemfc applications
Advanced Functional Materials, 2012Co-Authors: B P Vinayan, Rupali Nagar, N Rajalakshmi, Sundara RamaprabhuAbstract:A novel synthesis procedure is devised to obtain nitrogen-doping in hydrogen-exfoliated graphene (HEG) sheets. An anionic polyelectrolyte–conducting polymer duo is used to form a uniform coating of the polymer over graphene sheets. Pyrolysis of graphene coated with polypyrrole, a nitrogen-containing polymer, in an inert environment leads to the incorporation of nitrogen atoms in the graphene network with simultaneous removal of the polymer. These nitrogen-doped graphene (N-HEG) sheets are used as catalyst support for dispersing platinum and platinum–cobalt alloy nanoparticles synthesized by the modified-polyol reduction method, yielding a uniform dispersion of the catalyst nanoparticles. Compared to commercial Pt/C Electrocatalyst, Pt–Co/N-HEG cathode Electrocatalyst exhibits four times higher power density in proton exchange membrane fuel cells, which is attributed to the excellent dispersion of Pt–Co alloy nanoparticles on the N-HEG support, the alloying effect of Pt–Co, and the high electrocatalytic activity of the N-HEG support. A stability study shows that Pt/N-HEG and Pt–Co/N-HEG cathode Electrocatalysts are highly stable in acidic media. The study shows two promising Electrocatalysts for proton exchange membrane fuel cells, which on the basis of performance and stability present the possibility of replacing contemporary Electrocatalysts.
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novel platinum cobalt alloy nanoparticles dispersed on nitrogen doped graphene as a cathode Electrocatalyst for pemfc applications
Advanced Functional Materials, 2012Co-Authors: B P Vinayan, Rupali Nagar, N Rajalakshmi, Sundara RamaprabhuAbstract:A novel synthesis procedure is devised to obtain nitrogen-doping in hydrogen-exfoliated graphene (HEG) sheets. An anionic polyelectrolyte–conducting polymer duo is used to form a uniform coating of the polymer over graphene sheets. Pyrolysis of graphene coated with polypyrrole, a nitrogen-containing polymer, in an inert environment leads to the incorporation of nitrogen atoms in the graphene network with simultaneous removal of the polymer. These nitrogen-doped graphene (N-HEG) sheets are used as catalyst support for dispersing platinum and platinum–cobalt alloy nanoparticles synthesized by the modified-polyol reduction method, yielding a uniform dispersion of the catalyst nanoparticles. Compared to commercial Pt/C Electrocatalyst, Pt–Co/N-HEG cathode Electrocatalyst exhibits four times higher power density in proton exchange membrane fuel cells, which is attributed to the excellent dispersion of Pt–Co alloy nanoparticles on the N-HEG support, the alloying effect of Pt–Co, and the high electrocatalytic activity of the N-HEG support. A stability study shows that Pt/N-HEG and Pt–Co/N-HEG cathode Electrocatalysts are highly stable in acidic media. The study shows two promising Electrocatalysts for proton exchange membrane fuel cells, which on the basis of performance and stability present the possibility of replacing contemporary Electrocatalysts.
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cobalt polypyrrole multiwalled carbon nanotube catalysts for hydrogen and alcohol fuel cells
Carbon, 2008Co-Authors: Arava Leela Mohana Reddy, Natarajan Rajalakshmi, Sundara RamaprabhuAbstract:Abstract A cobalt-polymer-MWCNT composite has been developed as an Electrocatalyst for the oxygen reduction reaction (ORR) in PEMFC. The suitability of this Electrocatalyst for the ORR in direct methanol fuel cells and direct ethanol fuel cells has been examined by taking Pt–Ru/MWCNT and Pt–Sn/MWCNT, respectively as an anode Electrocatalysts. The study results in improved power densities for hydrogen, methanol and ethanol based fuel cells compared to the previously reported non Pt based Electrocatalysts, highlighting the use of this cobalt-polymer-MWCNT composite as a potential candidate for ORR in fuel cells.
Sebastian Watzele - One of the best experts on this subject based on the ideXlab platform.
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unprecedented high oxygen evolution activity of Electrocatalysts derived from surface mounted metal organic frameworks
Journal of the American Chemical Society, 2019Co-Authors: Sebastian Watzele, Hany A Elsayed, Yunchang Liang, Gregor Kieslich, Aliaksandr S Bandarenka, Katia Rodewald, Bernhard RiegerAbstract:The oxygen evolution reaction (OER) is a key process for renewable energy storage. However, developing non-noble metal OER Electrocatalysts with high activity, long durability and scalability remains a major challenge. Herein, high OER activity and stability in alkaline solution were discovered for mixed nickel/cobalt hydroxide Electrocatalysts, which were derived in one-step procedure from oriented surface-mounted metal–organic framework (SURMOF) thin films that had been directly grown layer-by-layer on macro- and microelectrode substrates. The obtained mass activity of ∼2.5 mA·μg–1 at the defined overpotential of 300 mV is 1 order of magnitude higher than that of the benchmarked IrO2 Electrocatalyst and at least 3.5 times higher than the mass activity of any state-of-the-art NiFe-, FeCoW-, or NiCo-based Electrocatalysts reported in the literature. The excellent morphology of the SURMOF-derived ultrathin Electrocatalyst coating led to a high exposure of the most active Ni- and Co-based sites.
Shizhang Qiao - One of the best experts on this subject based on the ideXlab platform.
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the ampoule method a pathway towards controllable synthesis of Electrocatalysts for water electrolysis
Chemistry: A European Journal, 2019Co-Authors: Yongqiang Zhao, Anthony Vasileff, Yan Jiao, Shizhang QiaoAbstract:: The ampoule method provides a promising pathway towards the controllable synthesis of novel Electrocatalysts for water electrolysis due to its straightforward manipulation of reaction conditions, accessible experimental design, and controlled environment. This Concept introduces the development of the ampoule method and anticipates its application in Electrocatalyst synthesis for water electrolysis. First, the history, device configuration, and merits of the ampoule method are briefly introduced. Afterwards, typical materials synthesized by the ampoule method are discussed. Then, recent process in applying the ampoule method to synthesize Electrocatalysts for water electrolysis is highlighted. Finally, opportunities and potentials of this method in facilitating Electrocatalyst synthesis for water electrolysis are discussed.
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Approaches for measuring the surface areas of metal oxide Electrocatalysts for determining their intrinsic electrocatalytic activity
Chemical Society Reviews, 2019Co-Authors: Chao Wei, Shengnan Sun, Daniel Mandler, Xun Wang, Shizhang QiaoAbstract:Great attention has been recently drawn to metal oxide Electrocatalysts for electrocatalysis-based energy storage and conversion devices. To find the optimal Electrocatalyst, a prerequisite is an activity metric that reasonably evaluates the intrinsic electrocatalytic activity of a particular catalyst. The intrinsic activity is commonly defined as the specific activity which is the current per unit catalyst surface area. Thus, the precise assessment of intrinsic activity highly depends on the reliable measurement of catalyst surface area, which calls for the knowledge of experimental approaches for determining the surface areas of metal oxide Electrocatalysts. This tutorial review aims to summarize and analyze the approaches for measuring the surface areas of metal oxide Electrocatalysts for evaluating and comparing their intrinsic electrocatalytic activities. We start by comparing the popular metrics for activity estimation and highlighting the importance of surface-area-normalized activity (i.e. specific activity) for intrinsic chemistry analysis. Second, we provide some general guidelines for experimentally measuring the electrochemically active surface area (ECSA). Third, we review the methods for the surface area measurement of metal oxide Electrocatalysts. The detailed procedure for each method is explicitly described to provide a step-by-step manual that guides researchers to perform the measurement; the rationales and uncertainties for each method are discussed to help readers justify the reliable assessment of surface area. Next, we give our recommendations on selecting a rational experimental approach for the surface area measurement of a particular metal oxide Electrocatalyst. Lastly, we discuss the future challenges of ECSA measurement and present an exemplary novel ECSA technique.
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transition metal doped ruir bifunctional nanocrystals for overall water splitting in acidic environments
Advanced Materials, 2019Co-Authors: Jieqiong Shan, Shizhang Qiao, Tao Ling, K R Davey, Yao ZhengAbstract:The establishment of Electrocatalysts with bifunctionality for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic environments is necessary for the development of proton exchange membrane (PEM) water electrolyzers for the production of clean hydrogen fuel. RuIr alloy is considered to be a promising Electrocatalyst because of its favorable OER performance and potential for HER. Here, the design of a bifunctional Electrocatalyst with greatly boosted water-splitting performance from doping RuIr alloy nanocrystals with transition metals that modify electronic structure and binding strength of reaction intermediates is reported. Significantly, Co-RuIr results in small overpotentials of 235 mV for OER and 14 mV for HER (@ 10 mA cm-2 current density) in 0.1 m HClO4 media. Therefore a cell voltage of just 1.52 V is needed for overall water splitting to produce hydrogen and oxygen. More importantly, for a series of M-RuIr (M = Co, Ni, Fe), the catalytic activity dependence at fundamental level on the chemical/valence states is used to establish a novel composition-activity relationship. This permits new design principles for bifunctional Electrocatalysts.
Bernhard Rieger - One of the best experts on this subject based on the ideXlab platform.
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unprecedented high oxygen evolution activity of Electrocatalysts derived from surface mounted metal organic frameworks
Journal of the American Chemical Society, 2019Co-Authors: Sebastian Watzele, Hany A Elsayed, Yunchang Liang, Gregor Kieslich, Aliaksandr S Bandarenka, Katia Rodewald, Bernhard RiegerAbstract:The oxygen evolution reaction (OER) is a key process for renewable energy storage. However, developing non-noble metal OER Electrocatalysts with high activity, long durability and scalability remains a major challenge. Herein, high OER activity and stability in alkaline solution were discovered for mixed nickel/cobalt hydroxide Electrocatalysts, which were derived in one-step procedure from oriented surface-mounted metal–organic framework (SURMOF) thin films that had been directly grown layer-by-layer on macro- and microelectrode substrates. The obtained mass activity of ∼2.5 mA·μg–1 at the defined overpotential of 300 mV is 1 order of magnitude higher than that of the benchmarked IrO2 Electrocatalyst and at least 3.5 times higher than the mass activity of any state-of-the-art NiFe-, FeCoW-, or NiCo-based Electrocatalysts reported in the literature. The excellent morphology of the SURMOF-derived ultrathin Electrocatalyst coating led to a high exposure of the most active Ni- and Co-based sites.