The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Mats Svensson - One of the best experts on this subject based on the ideXlab platform.
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experimental and theoretical study of oxidative addition reaction of Nickel Atom to o h bond of water
Journal of Chemical Physics, 1994Co-Authors: Steven A Mitchell, Per E M Siegbahn, Mark A Blitz, Mats SvenssonAbstract:The reaction of Atomic Nickel with water in the gas phase has been investigated by kinetic studies under static pressure conditions near room temperature, and by accurate quantum chemical calculations. Experimental and theoretical results are consistent with a reaction mechanism involving formation of a weakly bound Nickel–water adduct, which may react further by oxidative addition of Nickel to the O–H bond of water to form the insertion product HNiOH. Experimental estimates of reaction energetics have been made by using unimolecular reaction theory calculations to model rate coefficients obtained by fitting kinetic data to a simple rate equations model. These experimental estimates are in agreement with the theoretical results, and indicate that the insertion product is bound by at least 20–25 kcal/mol, relative to Nickel plus water. There is also agreement that the barrier to oxidative addition is no greater than 1–2 kcal/mol, and may be smaller. This theoretical result was obtained only at the highest ...
Steven A Mitchell - One of the best experts on this subject based on the ideXlab platform.
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experimental and theoretical study of oxidative addition reaction of Nickel Atom to o h bond of water
Journal of Chemical Physics, 1994Co-Authors: Steven A Mitchell, Per E M Siegbahn, Mark A Blitz, Mats SvenssonAbstract:The reaction of Atomic Nickel with water in the gas phase has been investigated by kinetic studies under static pressure conditions near room temperature, and by accurate quantum chemical calculations. Experimental and theoretical results are consistent with a reaction mechanism involving formation of a weakly bound Nickel–water adduct, which may react further by oxidative addition of Nickel to the O–H bond of water to form the insertion product HNiOH. Experimental estimates of reaction energetics have been made by using unimolecular reaction theory calculations to model rate coefficients obtained by fitting kinetic data to a simple rate equations model. These experimental estimates are in agreement with the theoretical results, and indicate that the insertion product is bound by at least 20–25 kcal/mol, relative to Nickel plus water. There is also agreement that the barrier to oxidative addition is no greater than 1–2 kcal/mol, and may be smaller. This theoretical result was obtained only at the highest ...
Zhaoyong Bian - One of the best experts on this subject based on the ideXlab platform.
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graphene supported single Nickel Atom catalyst for highly selective and efficient hydrogen peroxide production
ACS Applied Materials & Interfaces, 2020Co-Authors: Xiaozhe Song, Huan Zhang, Li Wang, Yanjun Yan, Hui Wang, Linyuan Wang, Zhaoyong BianAbstract:Hydrogen peroxide (H2O2) production by electrocatalytic two-electron oxygen reduction shows promise as a replacement for energy-intensive anthraquinone oxidation or H2/O2 direct synthesis. Here, we report on graphene-supported Ni single-Atom (SA) electrocatalysts, which are synthesized by a simple surfactant-free reduction process with enhanced electrocatalytic activity and stability. Unlike conventional Ni nanoparticles or alloy catalysts, the well-dispersed Ni-SA sites lack adjacent Ni Atoms. This structure promotes H2O2 production by a two-electron oxygen reduction pathway under an alkaline condition (pH = 13). This catalyst exhibited enhanced H2O2 selectivity (>94%) with a considerable mass activity (2.11 A mgNi-1 at 0.60 V vs reversible hydrogen electrode), owing to the presence of oxygen functional groups and isolated Ni sites. Density functional theory calculations provide insights into the role of this catalyst in optimizing the two-electron oxygen reduction reaction pathway with high H2O2 selectivity. This work suggests a new method for controlling reaction pathways in Atomically dispersed non-noble catalysts.
Yuanyue Liu - One of the best experts on this subject based on the ideXlab platform.
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unveiling the active structure of single Nickel Atom catalysis critical roles of charge capacity and hydrogen bonding
Journal of the American Chemical Society, 2020Co-Authors: Xunhua Zhao, Yuanyue LiuAbstract:A single Nickel Atom embedded in graphene is one of the most representative single-Atom catalysts, and it has a high activity and selectivity for electrochemical CO2 reduction (CO2R) to CO. However, the catalytic origin, especially the coordination structure of Ni, remains highly puzzling, as previous density functional theory (DFT) calculations showed that all the possible structures should be inactive and/or nonselective. Here, using ab initio molecular dynamics (AIMD) and a "slow-growth" sampling approach to evaluate the reaction kinetic barriers, we show that the charge capacity (of the site) and hydrogen bonding (with the intermediates), which were neglected/oversimplified in previous DFT calculations, play crucial roles, and including their effects can resolve the catalytic origin. Particularly, a high charge capacity allows the catalytic site to carry more charges than required for the electrochemical step, lowering the electrochemical barrier, and hydrogen bonding promotes the reaction that produces polar intermediates by stabilizing the intermediates and facilitating the H transfer from water, explaining the high selectivity for CO2R over the hydrogen evolution reaction. Consequently, we find that a hybrid coordination environment (with one nitrogen and three carbon Atoms) for the Ni-Atom is most active and selective for CO2R. Our work not only explains a long-standing puzzle for an important catalyst but also highlights the crucial roles of charge capacity and hydrogen bonding, which can help elucidate the mechanisms of other heterogeneous electrocatalysts in aqueous solution and enable more effective catalyst design.
Jinlan Wang - One of the best experts on this subject based on the ideXlab platform.
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nanosheet supported single metal Atom bifunctional catalyst for overall water splitting
Nano Letters, 2017Co-Authors: Chongyi Ling, Li Shi, Yixin Ouyang, Xiao Cheng Zeng, Jinlan WangAbstract:Nanosheet supported single-Atom catalysts (SACs) can make full use of metal Atoms and yet entail high selectivity and activity, and bifunctional catalysts can enable higher performance while lowering the cost than two separate unifunctional catalysts. Supported single-Atom bifunctional catalysts are therefore of great economic interest and scientific importance. Here, on the basis of first-principles computations, we report a design of the first single-Atom bifunctional eletrocatalyst, namely, isolated Nickel Atom supported on β12 boron monolayer (Ni1/β12-BM), to achieve overall water splitting. This nanosheet supported SAC exhibits remarkable electrocatalytic performance with the computed overpotential for oxygen/hydrogen evolution reaction being just 0.40/0.06 V. The ab initio molecular dynamics simulation shows that the SAC can survive up to 800 K elevated temperature, while enacting a high energy barrier of 1.68 eV to prevent isolated Ni Atoms from clustering. A viable experimental route for the synth...