Noble metals are downsized to nano-/subnanoscale to improve their catalytic activity and atom-economy.However,the stabilities in chemical state and catalytic performance of these nanocatalysts often suffer during hars...Noble metals are downsized to nano-/subnanoscale to improve their catalytic activity and atom-economy.However,the stabilities in chemical state and catalytic performance of these nanocatalysts often suffer during harsh conditions.For Pt nanoparticles(NPs)supported on CeO2,activated oxygen diffused from the support over-stabilizes the active sites of Pt,degrading its performance at mild temperature.In this work,Pt nanocatalysts with unique structure of triple-junction are synthesized by selectively growing Pt NPs on the carbon-CeO2 interface.Impressively,the Pt NPs exhibit much enhanced catalytic stability and high activity for CO oxidation at mild temperature.The enhancement is attributed to electron donation from graphitized carbon and the confinement effect from the high-density nanopores of the CeO2 support.The triple-junction of Pt-C-CeO2,combining the merits of CeO2 for activating O2 and electron donating capability of carbon,provides new inspiration to the fabrication of high-performance nanocatalysts.展开更多
Asymmetric hydrogenation of ethyl pyruvate was studied on nano Pt catalyst stabilized by PEG or PVA in the presence of cinchonidine. The ee value decreases due to the effect between -OH in the PVA and the catalyst.
PEG-stabilized platinum nanoparticles with uniform size were prepared successfully. They did not precipitate after being stored for four months. The nanoparticles show high catalytic activity for hydrogenation of styr...PEG-stabilized platinum nanoparticles with uniform size were prepared successfully. They did not precipitate after being stored for four months. The nanoparticles show high catalytic activity for hydrogenation of styrene and selectivity of long chain olefins. The platinum nanoparticles modified by cinchonidine give 85.6% e.e selectivity in asymmetric hydrogenation of ethyl pyruvate.展开更多
基金supported by the National Key Research and Development Program of China(2016YFB0701100)the National Natural Science Foundation of China(51771047,51525101 and 51971059)the Fundamental Research Funds for the Central Universities(N180204014)。
文摘Noble metals are downsized to nano-/subnanoscale to improve their catalytic activity and atom-economy.However,the stabilities in chemical state and catalytic performance of these nanocatalysts often suffer during harsh conditions.For Pt nanoparticles(NPs)supported on CeO2,activated oxygen diffused from the support over-stabilizes the active sites of Pt,degrading its performance at mild temperature.In this work,Pt nanocatalysts with unique structure of triple-junction are synthesized by selectively growing Pt NPs on the carbon-CeO2 interface.Impressively,the Pt NPs exhibit much enhanced catalytic stability and high activity for CO oxidation at mild temperature.The enhancement is attributed to electron donation from graphitized carbon and the confinement effect from the high-density nanopores of the CeO2 support.The triple-junction of Pt-C-CeO2,combining the merits of CeO2 for activating O2 and electron donating capability of carbon,provides new inspiration to the fabrication of high-performance nanocatalysts.
文摘Asymmetric hydrogenation of ethyl pyruvate was studied on nano Pt catalyst stabilized by PEG or PVA in the presence of cinchonidine. The ee value decreases due to the effect between -OH in the PVA and the catalyst.
文摘PEG-stabilized platinum nanoparticles with uniform size were prepared successfully. They did not precipitate after being stored for four months. The nanoparticles show high catalytic activity for hydrogenation of styrene and selectivity of long chain olefins. The platinum nanoparticles modified by cinchonidine give 85.6% e.e selectivity in asymmetric hydrogenation of ethyl pyruvate.
