Ordered intermetallic PtBi had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of liquid formic acid on PtBi was investigated at room temperature by cyclic voltammetry and chronoampe...Ordered intermetallic PtBi had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of liquid formic acid on PtBi was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results are compared to those at a polycrystalline platinum electrode surface. At PtBi surface the onset potential for formic acid oxidation is shifted negatively by over 250 mV and the current density at the PtBi electrode is about ten multiple higher than that of Pt electrode. XRD and XPS technologies had been used to investigate the crystal structure and electron effect. We propose that formic acid decomposition on PtBi favors the reactive intermediate route and is not very much affected by the CO intermediate compared with Pt according to the results of electrochemical test and ex-site FTIR test.展开更多
The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surf...The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surfactants on the surface of the assynthesized catalysts would prevent the exposure of catalytic active sites,the high-temperature annealing process is easy to accelerate the sintering of the metal,which both lead to the decline of electrocatalytic performance.Herein,we construct the atomically ordered bimetallic PtBi intermetallics with clean surfaces and unique three-dimensional hollow acorn-shell-like structure(3D PtBi HASL)by a simple,low-temperature,surfactant-free one-pot synthetic approach.Benefiting from the special hollow structures,the obtained 3D PtBi HASL intermetallics expose abundant accessible active sites.Moreover,the introduction of oxophilic metal Bi can enhance adsorption of OHads,thereby significantly facilitating removal of poisoned intermediates.Density functional theory(DFT)simulations further indicate that formation of the PtBi intermetallic phase with the downshift of the Pt d-band center endows 3D Pt49.4Bi50.6 HASL intermetallics with significantly attenuated COads and enhanced OHads adsorption,bringing about the boosting electrocatalytic property.The mass activity of the 3D Pt49.4Bi50.6 HASL intermetallics for ethylene glycol oxidation reaction is as high as 24.67 A·mgPt^(−1),which is 12.98 times higher than that of commercial Pt/C(1.90 A·mgPt^(−1)).This work may inspire the design of Pt-based intermetallics as high-efficiency anode electrocatalysts for fuel cell applications.展开更多
We present the systematic de Haas–van Alphen(d Hv A) quantum oscillations studies on the recently discovered topological Dirac semimetal pyrite PtBi2 single crystals. Remarkable d Hv A oscillations are emerged at a l...We present the systematic de Haas–van Alphen(d Hv A) quantum oscillations studies on the recently discovered topological Dirac semimetal pyrite PtBi2 single crystals. Remarkable d Hv A oscillations are emerged at a low field about 1.5 T. From the analyses of the d Hv A oscillations, we extract the high quantum mobilities, light effective masses and phase shift factors for the Dirac fermions in pyrite PtBi2. From the angular dependence of the d Hv A oscillations, we map out the topology of the Fermi surface.Furthermore, we identify two additional oscillation frequencies that are not probed by the Sd H oscillations, which provides us with opportunities to further understand its Fermi surface topology.展开更多
文摘Ordered intermetallic PtBi had been synthesized by arc-melted and then sintering treatment. The electro-oxidation of liquid formic acid on PtBi was investigated at room temperature by cyclic voltammetry and chronoamperometry. The results are compared to those at a polycrystalline platinum electrode surface. At PtBi surface the onset potential for formic acid oxidation is shifted negatively by over 250 mV and the current density at the PtBi electrode is about ten multiple higher than that of Pt electrode. XRD and XPS technologies had been used to investigate the crystal structure and electron effect. We propose that formic acid decomposition on PtBi favors the reactive intermediate route and is not very much affected by the CO intermediate compared with Pt according to the results of electrochemical test and ex-site FTIR test.
基金the Natural Science Foundation of Anhui Province(Nos.2108085MB55 and 2208085MB24)the National Natural Science Foundation of China(Nos.21571001,21706048,and 21701001)the Natural Science Research Project of Anhui Province(Nos.KJ2021A0004 and KJ2020ZD04).
文摘The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surfactants on the surface of the assynthesized catalysts would prevent the exposure of catalytic active sites,the high-temperature annealing process is easy to accelerate the sintering of the metal,which both lead to the decline of electrocatalytic performance.Herein,we construct the atomically ordered bimetallic PtBi intermetallics with clean surfaces and unique three-dimensional hollow acorn-shell-like structure(3D PtBi HASL)by a simple,low-temperature,surfactant-free one-pot synthetic approach.Benefiting from the special hollow structures,the obtained 3D PtBi HASL intermetallics expose abundant accessible active sites.Moreover,the introduction of oxophilic metal Bi can enhance adsorption of OHads,thereby significantly facilitating removal of poisoned intermediates.Density functional theory(DFT)simulations further indicate that formation of the PtBi intermetallic phase with the downshift of the Pt d-band center endows 3D Pt49.4Bi50.6 HASL intermetallics with significantly attenuated COads and enhanced OHads adsorption,bringing about the boosting electrocatalytic property.The mass activity of the 3D Pt49.4Bi50.6 HASL intermetallics for ethylene glycol oxidation reaction is as high as 24.67 A·mgPt^(−1),which is 12.98 times higher than that of commercial Pt/C(1.90 A·mgPt^(−1)).This work may inspire the design of Pt-based intermetallics as high-efficiency anode electrocatalysts for fuel cell applications.
基金supported by the National Key Research and Development Program of China(2016YFA0401003)the National Natural Science Foundation of China(11774353,11574320,11204312,11674331,11474289,11804340,and U1732274)+3 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017483)the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology(2018CXFX002)the Chinese Academy of Sciences Pioneer Hundred Talents Programthe Natural Science Foundation of Anhui Province(1908085QA15)
文摘We present the systematic de Haas–van Alphen(d Hv A) quantum oscillations studies on the recently discovered topological Dirac semimetal pyrite PtBi2 single crystals. Remarkable d Hv A oscillations are emerged at a low field about 1.5 T. From the analyses of the d Hv A oscillations, we extract the high quantum mobilities, light effective masses and phase shift factors for the Dirac fermions in pyrite PtBi2. From the angular dependence of the d Hv A oscillations, we map out the topology of the Fermi surface.Furthermore, we identify two additional oscillation frequencies that are not probed by the Sd H oscillations, which provides us with opportunities to further understand its Fermi surface topology.
