Photo/electrocatalytic Synthesis Of Fine Chemicals With Copper-based Nanomaterials

In recent years,nanomaterial has attracted widespread attention in the field of catalysis due to its high catalytic activity,large specific surface area and recyclability.Among them,the abundant and low-cost copper-based materials have been widely used in energy conversion and utilization including photocatalytic organic synthesis and electrocatalytic carbon dioxide reduction.In photocatalytic organic synthesis,copper-based nanomaterials have been used as efficient photocatalysts for C-C,C-N,C-O,and C-S bond formation with high selectivity and yield under mild reaction conditions.Traditionally,these bonds are formed utilizingnoble metal catalysts under harsh reaction conditions with the addition of large amounts of ligands,limiting its application in industry.In the electrocatalytic carbon dioxide reduction reaction（CO₂RR）,bulk copper catalyst can convert CO₂into hydrocarbons,such as methane,ethylene,ethane,ethanol,etc.However,higher overpotential is required and product selectivity is low.Therefore,it is necessary to design an efficient catalyst with high selectivity.Thus,the research content of this paper is as follows:1.Using carbon nanotubes（CNTs）as supports,Cu_xO/CNTs catalysts were prepared by the impregnation method.The particle size of the supported Cu_xO nanoparticles was 1-3 nm,and the average particle size was 1.96±0.75 nm.Then,utilizing iodobenzene and phenylacetylene as typical reactantd,we investigated the effects of reaction temperature,reaction time,light wavelength,light intensity,solvent,support,alkali and etc on the catalytic activity.The results showed that light could tune the Glaser self-coupling to Sonogashira cross-coupling and the active species under light irradiation is different from that in the dark.Phenylacetylide copper（I）is the active species for Sonogashira coupling under light rather than that for Glaser coulping in the dark.Finally,the possible mechanism of photocatalytic Sonogashira coupling reaction was proposed.2.Using electropolished copper foil as substrate,we prepared Cu electrode with three-dimentional（3D）nano sharp tip structures by electrodepositon in a mixed solution of Cu²⁺and phosphate.Then,an oxidation-reduction-derived 3D Cu nano sharp tip was obtained by annealing and in-situ electroreduction.Electrocatalytic CO₂reduction was performed with the prepared electrode in 0.1 M KHCO₃electrolyte saturated with CO₂.The results showed that C₂H₄/CH₄was up to 21.7 at-1.2 V vs.RHE and FE of HCOOH was 36%at-0.9 V vs.RHE,which is respectively 90.6times and 6.8 times of electropolished copper foil.Through the inductively coupled plasma test,we proved that the nano-tip structure was favorable for the adsorption of K⁺and the corresponding HCO₃^-,in turn promoing CO₂reduction.