Carbon Dioxide / Methanol Electrochemical Synthesis Of Dimethyl Carbonate Electro-catalytic Materials

This paper is focusing on designing and fabricating a novel nanoporous metallic material-nanoporous copper (NPC) and exploring its corresponding formation mechanism, crystal structure and electrocatalytic properties. The effect of thermal treated temperature and electro-deposition time were investigated. The optimum process of synthesizing NPC is listed as follows:the copper was electrodeposited Zn for 10 min, and then calcined at 200℃for 2 h. Finally, chemical dealloying was carried out in the HCl (pH=4) aqueous solution at room temperature for 24 h.Dealloying was used to synthesize nanoporous metals to act as sacrificial templates, hydrazine hydrate as a reduction agent, and followed by reacting with H2PtCl6 or AgNO3 solution precursors to fabricate NPC-Pt and NPC-Ag. The resulted structures show a three-dimentional bicontinuous nanotubular porous structure. NPC-Pt catalyst exhibits high catalytic activity towards electrochemical reduction of CO2.Electroactivation of CO2 to organic carbonates with methanol in ionic liquid was relized. It provies a clean and new route to synthesis DMC. The effects of temperture, electrodes, working potentials and concentration of methanol etc on the yield of DMC have been examined to optimize the synthetic conditions. After optimizing the synthetic parameters, the yield reached 77.3% on NPC-Pt electrde at a constant potential of-2.0 V vs. Ag until 1.0 F/mol of charge passed through the cell when 0.14 mol/L methanol was applied at 55℃in ionic liquid BmimBF4. Furthermore, the ionic liquid can be recycled. The mechanism is proposed that CO2.-, which is formed by CO2 reduciton and stable through the formation of CO2.-—Bmim+ ion-paring, reacted with the methanol to form the aim product after addition of alkylatin agent.Polyaniline/Ag nanocomposites have been synthesized via in-situ chemical oxidation polymerization of aniline in silver salt by sonochemical method using ammonium perfulfate (APS) as an external medium. APS was used both to reduce AgNO3 to Ag nanoparticles and to polymerize aniline in an acidic pH solution. This technique utilizes ultrasound radiation as an energy source to facilitate the reaction by enhancing rate, as well as significantly increasing the yield. X-ray diffraction measurement showed the presence of Ag in the composite in addition to indicating the formation of polyaniline with low crystalline phase in the case. UV-visible absorption spectra and FT-IR spectra indicated the formation of emeraldine salt form in the polyaniline/Ag nanocomposite. The product exhibits a spherical and granular nature. The result indicated that the formation of aggregated silver nanoparticles, with the polyaniline formed around aggregated or individual nanoparticles.The cyclic voltammetry results showed that the polyaniline/Ag film exhibits considerably higher electroactivity compared with polyaniline film without Ag particles. The electrocatalytic reduction of cabon dioxide of polyaniline was not changed by the embedment of silver particles inside the polyaniline matrix.