Study On Electronic Structure Control And Catalytic Performance Of Copper Matrix Composites

Copper-based composites are widely concerned in electrocatalysis,tail gas treatment,photocatalysis and so on because of their low price and excellent catalytic performance.For heterogeneous catalysis,chemical reactions usually occur on the surface and interface of solid catalyst,and the design of electronic surface and interface state is very important to improve the catalytic activity of catalyst.Therefore,in this paper,the electronic state of the surface and interface of copper matrix composites is regulated(metal-carrier interaction,surface control and interface control),the regulation mechanism of the electronic control of the surface interface is explored,the relationship between the surface electronic state and the catalytic performance of atomic scale materials is studied,and the optimization mechanism of the surface electronic structure is deeply studied,thus laying a solid foundation for the development of a new generation of high-efficiency copper-based matrix composite material catalysts.The main contents and conclusions of the study are as follows:(1)Cu/Zn1-x Cux O(Cu/ZCO)composite catalysts were prepared by electrostatic spinning to activate surface lattice oxygen for catalytic CO oxidation,and the metal-carrier interactions and oxidation mechanisms were investigated.Cu/ZCO had a lower activation energy for CO oxidation(52.3k J·mol-1).These results consistently demonstrate that the reactive sites in Cu/ZCO are more active,significantly increasing the intrinsic catalytic activity for CO oxidation.the Cu/ZCO catalysts exhibit strong electron transfer effects between the copper metal and oxide carriers,and the surface lattice oxygen of Cu/ZCO is effectively activated with a significant increase in the species of oxygen adsorbed on its surface.Furthermore,online isotope mass spectrometry showed that the activation of surface lattice oxygen of Cu/ZCO significantly increased the efficiency of the Mars-van Krevelen(Mv K)mechanism during CO oxidation,while the reaction efficiency of the Langmuir-Hinshelwood(L-H)mechanism of Cu/ZCO did not change significantly compared to that of CuZCO.This result suggests that the reaction efficiency of the L-H mechanism is mainly related to the surface copper nanoparticles on the carrier,whereas the Mv K mechanism is mainly determined by the activity of the copper nanoparticles and surface lattice oxygen.Therefore,the Cu/ZCO catalyst showed better catalytic activity and durability in the CO oxidation process.(2)The Cu2 O with different hydrophobic degree was prepared by surface modification by coating the surface of rhombic dodecahedral Cu2 O with different contents of octadecylamine.The results showed that the amount of octadecylamine coating affects the electron transfer between octadecylamine and Cu2 O,thus on affecting the photocatalytic CO2 reduction performance of the catalyst.When the content of octadecylamine increased,the material took on a superhydrophobic nature,with a significant increase in the amount of adsorbed oxygen species on the surface of the superhydrophobic material,and a significant increase in carbonate adsorbed species,which was more favourable for CO2 reduction.Compared with the pristine and low hydrophobic samples,the liquid and gaseous products of superhydrophobic Cu2 O were substantially increased,including ethanol conversion of 84.64 μmol g-1 h-1,and the ethanol product selectivity reached 100%,with the prospect of industrial mass production of ethanol,compounding the scientific ecological development concept.(3)Electrodeposition was used to grow cuprous oxide on different substrates,and the effects of different electrodeposition times and different substrate growths on the CO2 reduction performance were investigated.Ti/Cu2O60 showed better catalytic activity,indicating that 60 s is the optimal condition for electrodeposition time.Among the Ti/Cu2 O 60,Zn/Cu2 O 60,Ni/Cu2 O 60 and ITO/Cu2 O 60 samples,Ti/Cu2 O 60 performed better and the surface Ti flakes were more suitable for the growth substrate of cuprous oxide,and the Ti-Cu interaction was more suitable for CO2 reduction than the Zn-Cu,Ni-Cu and ITOCu interactions,with Ti/Cu2 O 60 had an ethanol conversion of 366.57 μmol g-1h-1 and a methanol conversion of 508.67 μmol g-1 h-1.