In the present work,a Pd/graphene/cordierite(Pd/Gr/Cor)composite was prepared as a monolithic catalyst for low-temperature combustion of toluene.We mainly focused on understanding the role of graphene coating through ...In the present work,a Pd/graphene/cordierite(Pd/Gr/Cor)composite was prepared as a monolithic catalyst for low-temperature combustion of toluene.We mainly focused on understanding the role of graphene coating through investigation of catalytic performance and adsorption behavior of the composite.Compared with the traditional Pd/Cor catalyst without graphene coating,Pd/Gr/Cor catalyst delivered much higher activity and stability for toluene catalytic combustion in both dry and moist conditions.Transmission electron microscopy(TEM)and hydrophobic characterizations indicated that graphene coating can considerably improve the dispersity of Pd nanoparticles and enhance the hydrophobicity of the cordierite support.The adsorption behavior of the above two catalysts,including adsorption isothermal,adsorption kinetics,and adsorption thermodynamics were carefully investigated.The simulation results indicated that a large amount of toluene was adsorbed on graphene surface through relatively weak interaction,whereas only a relatively small amount of toluene was adsorbed on Pd surface with strong affinity.The adsorption thermal calculation indicated that the adsorption of toluene on graphene was a process with reduced entropy,indicating highly-ordered assembly of toluene molecular on graphene.It is the significant concentration and affinity gap between graphene and Pd that ensures a simultaneously and rapid transfer of toluene during the reaction process.展开更多
An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the ...An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the modified Langmuir-Blodgett(LB)method,and the electrocatalytic oxidation of mononucleotide of guanosine 5′-monophosphate(GMP)on an ITO/TiO2-Ru electrode after Pd-photodeposition(denoted as ITO/TiO2-Ru/Pd)has been studied.Atomic force microscopy reveals that the single-layered hybrid film of TiO2 nanosheets/[Ru(phen)2(dC18bpy)] 2+is closely packed at a surface pressure of 25 mN m 1and has a thickness of(3.20±0.5)nm.X-ray photoelectron spectra show the formation of Pd nanoparticles on the surface of hybrid film with radii of 20–200 nm by the reduction of[Pd(NH3)4] 2+ under light irradiation.When it is applied to oxidize GMP,a larger catalytic oxidative current is achieved on the ITO/TiO2-Ru/Pd electrode at the external potential above 700 mV(vs.Ag|AgCl|KCl)in comparison with the naked ITO electrode and ITO/TiO2-Ru electrode.Such a result indicates that the Pd nanoparticles are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II)complexes,and thus develops the electron transfer efficiency and produces the enhanced redox current.展开更多
基金supported by the National Natural Science Foundation of China(21276284,21676303,21706292)~~
文摘In the present work,a Pd/graphene/cordierite(Pd/Gr/Cor)composite was prepared as a monolithic catalyst for low-temperature combustion of toluene.We mainly focused on understanding the role of graphene coating through investigation of catalytic performance and adsorption behavior of the composite.Compared with the traditional Pd/Cor catalyst without graphene coating,Pd/Gr/Cor catalyst delivered much higher activity and stability for toluene catalytic combustion in both dry and moist conditions.Transmission electron microscopy(TEM)and hydrophobic characterizations indicated that graphene coating can considerably improve the dispersity of Pd nanoparticles and enhance the hydrophobicity of the cordierite support.The adsorption behavior of the above two catalysts,including adsorption isothermal,adsorption kinetics,and adsorption thermodynamics were carefully investigated.The simulation results indicated that a large amount of toluene was adsorbed on graphene surface through relatively weak interaction,whereas only a relatively small amount of toluene was adsorbed on Pd surface with strong affinity.The adsorption thermal calculation indicated that the adsorption of toluene on graphene was a process with reduced entropy,indicating highly-ordered assembly of toluene molecular on graphene.It is the significant concentration and affinity gap between graphene and Pd that ensures a simultaneously and rapid transfer of toluene during the reaction process.
基金supported by the National Natural Science Foundation of China(21073133,20843007,20471043)Zhejiang Provincial Natural Science Foundation of China(Y5100283,Y4090248,Y4080177)Wenzhou University Foundation(2007L019)
文摘An indium tin oxide(ITO)electrode coated with monolayer TiO2/[Ru(phen)2(dC18bpy)] 2+ (phen=1,10-phenanthroline, dC18bpy=4,4′-dioctadecyl-2,2′-bipyridyl)hybrid film(denoted as ITO/TiO2-Ru)has been prepared using the modified Langmuir-Blodgett(LB)method,and the electrocatalytic oxidation of mononucleotide of guanosine 5′-monophosphate(GMP)on an ITO/TiO2-Ru electrode after Pd-photodeposition(denoted as ITO/TiO2-Ru/Pd)has been studied.Atomic force microscopy reveals that the single-layered hybrid film of TiO2 nanosheets/[Ru(phen)2(dC18bpy)] 2+is closely packed at a surface pressure of 25 mN m 1and has a thickness of(3.20±0.5)nm.X-ray photoelectron spectra show the formation of Pd nanoparticles on the surface of hybrid film with radii of 20–200 nm by the reduction of[Pd(NH3)4] 2+ under light irradiation.When it is applied to oxidize GMP,a larger catalytic oxidative current is achieved on the ITO/TiO2-Ru/Pd electrode at the external potential above 700 mV(vs.Ag|AgCl|KCl)in comparison with the naked ITO electrode and ITO/TiO2-Ru electrode.Such a result indicates that the Pd nanoparticles are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II)complexes,and thus develops the electron transfer efficiency and produces the enhanced redox current.
