Selective oxidation of 5-hydroxymethylfurfual(HMF) to 2,5-furandicarboxylic acid(FDCA) as a bioplastics monomer is efficiently promoted by a simple system without noble-metal and base additives. In this work, graphene...Selective oxidation of 5-hydroxymethylfurfual(HMF) to 2,5-furandicarboxylic acid(FDCA) as a bioplastics monomer is efficiently promoted by a simple system without noble-metal and base additives. In this work, graphene oxide(GO) was first synthesised by an electrochemical method with flexible graphite paper(FGP) as start carbon material, then, nitrogen-doped graphene(NG) layers encapsulated Cu nanoparticles(NPs) was prepared by one-step thermal treatment of GO supported Cu2+ in flowing NH3 atmosphere. Compared with NG supported Cu NPs prepared by the traditional impregnation method, enhanced catalytic activity was achieved over Cu/NG and an FDCA yield of 95.2% was achieved under mild reaction conditions with tert-butylhydroperoxide(t-BuOOH) as the oxidant. Control experiments with different catalysts and different addition procedure of t-BuOOH showed the yield of HMF and various intermediates during reaction. From the changing of intermediates concentrations and reaction rates, a reaction pathway through HMF-DFF-FFCA-FDCA was proposed. This work gives a more convenient, more green,more economical and effective method in encapsulated metal NPs preparation and high selectivity in HMF oxidation to FDCA under mild conditions.展开更多
Since the 1990s,the existence of water-ice in the permanent shadow areas of the lunar polar regions and the problem of water in the early lunar period have become the hot spot of international lunar exploration.This p...Since the 1990s,the existence of water-ice in the permanent shadow areas of the lunar polar regions and the problem of water in the early lunar period have become the hot spot of international lunar exploration.This paper analyzes the research progress and existing problems of lunar water-ice detection in recent years.Based on the analysis of expected foreign lunar water-ice exploration missions,the major scientific problems of lunar water-ice are analyzed.From different exploration methods,this paper tentatively puts forward the scientific tasks,payload configuration,functional requirements,and possible scientific outputs of water-ice in China's future lunar exploration projects,which can provide reference for future lunar exploration missions.展开更多
基金the National Natural Science Foundation of China(NNSFC)(21805145&U1610108)the Department of Science and Technology of Shandong Province(ZR2019BB068)+2 种基金the Department of Science and Technology of Shanxi Province(201705D211001)Scientific and Technological Innovation Programs of High Education Institutions in Shanxi(201802001-1)the Department of Human Resource and Social Security of Shanxi Province(Y6SW9613B1)。
文摘Selective oxidation of 5-hydroxymethylfurfual(HMF) to 2,5-furandicarboxylic acid(FDCA) as a bioplastics monomer is efficiently promoted by a simple system without noble-metal and base additives. In this work, graphene oxide(GO) was first synthesised by an electrochemical method with flexible graphite paper(FGP) as start carbon material, then, nitrogen-doped graphene(NG) layers encapsulated Cu nanoparticles(NPs) was prepared by one-step thermal treatment of GO supported Cu2+ in flowing NH3 atmosphere. Compared with NG supported Cu NPs prepared by the traditional impregnation method, enhanced catalytic activity was achieved over Cu/NG and an FDCA yield of 95.2% was achieved under mild reaction conditions with tert-butylhydroperoxide(t-BuOOH) as the oxidant. Control experiments with different catalysts and different addition procedure of t-BuOOH showed the yield of HMF and various intermediates during reaction. From the changing of intermediates concentrations and reaction rates, a reaction pathway through HMF-DFF-FFCA-FDCA was proposed. This work gives a more convenient, more green,more economical and effective method in encapsulated metal NPs preparation and high selectivity in HMF oxidation to FDCA under mild conditions.
基金supported by the National Key R&D Program of China(Grant No.2020YFE0202100).
文摘Since the 1990s,the existence of water-ice in the permanent shadow areas of the lunar polar regions and the problem of water in the early lunar period have become the hot spot of international lunar exploration.This paper analyzes the research progress and existing problems of lunar water-ice detection in recent years.Based on the analysis of expected foreign lunar water-ice exploration missions,the major scientific problems of lunar water-ice are analyzed.From different exploration methods,this paper tentatively puts forward the scientific tasks,payload configuration,functional requirements,and possible scientific outputs of water-ice in China's future lunar exploration projects,which can provide reference for future lunar exploration missions.
