Electroactive Carbon Dioxide To Synthesize Ethanol

In the past few centuries, the rapid development of science and technology brought many convenient to human life. At the same time it caused great destruction on the natural environment. One of the most concerned environmental problem is the greenhouse effect. Main reason of the greenhouse effect is the large amounts of emissions of greenhouse gases, and damage of the large areas of forest and vegetation. Greenhouse effect can cause the climate problem such as global warming, the resulting natural disasters have caused great loss to the people in many parts of the world. How to alleviate the greenhouse effect is a common problem faced by people all over the world. CO2is the largest contributor to the greenhouse effect, at the same time is a kind of naturally abundant cheap, nontoxic building block in the organic synthesis. The capture and transformation of CO2can not only alleviate the greenhouse effect, but also get many useful substances. Therefore, countries all over the world are paid close attention to CO2fixation.CO2is linear symmetric molecule, high oxide of C, and has high chemical stability. Therefore, traditional method of CO2fixation needs tough conditions, often use strong reducing agent or need high temperature and high pressure. In electrochemical synthesis, the substrate could be reduced or oxidized by getting or losing electrons, avoiding the use of other oxidizing or reducing agent in the process. It has received considerable attention because of many favorable properties, such as mild reaction conditions, high selectivity, low pollution and low cost. Electrochemical fixation of CO2is a kind of green synthesis method.Ethanol and normal propyl alcohol is important basic chemical materials, widely used in pharmaceutical, pesticide, cosmetics synthetic, and can also be used for production of spices, food additives, plasticizer and many other aspects. Additionally, ethanol can be used as a gasoline additive, improving performance and quality of gasoline and reducing emissions of carbon monoxide, hydrocarbons, etc. Moreover, it is a potential substitute for petrol. Ethanol is synthesized via syngas in traditional industry, but it has many disadvantages, such as low selectivity, harsh reaction conditions (high temperature and high pressure), consuming of large amounts of hydrogen, etc. In aqueous solution, using electrochemical methods to reduction of CO2for synthesis of small molecule alcohols has important research significance, because of the mild reaction conditions, green, pollution-free process.The details are given as follows:(1) The preparation of cuprous oxide nanoparticles modified electrodeThe cuprous oxide nanoparticles modified electrode was prepared by the method of potentiostatic deposition. The electrodeposition was performed in undivided cell equipped with Cu plates as the cathode or anode, and a SCE as the reference electrode. In a typical synthesis Cu2O film was deposition from a Cu(II) lactic acid solution. XRD and SEM have been used to characterize crystal type and morphology of the modified electrodes. The various influence factors in the process of deposition have been investigated. The prepared modified electrode has been tried to electrocatalytic reduction of CO2.(2) Copper oxide electrode catalyzes the reduction of CO2Nano-copper oxide modified electrodes were fabricated by potentiostatic deposition and high temperature oxidation. Electrochemical reduction of CO2has been carried out in a divided cell equipped with a modified electrode as the cathode, a Pt mesh as the anode, and a SCE as the reference electrode. The reaction was developed in the presence of atmosphere pressure of CO2in aqueous solution. Ethanol and normal propyl alcohol was obtained under potentiostatic control. The influence of some operational factors in the electrode making process, such as the oxide temperature and the charge of copper deposition, has been investigated. Furthermore, the electrolytic conditions, such as potential, charge, supporting electrolytes, have been investigated.(3) Reduction of CO2using multi-potential stepsThe multi-potential steps method was adopted to electrochemical reduction of CO2in aqueous solution. The electrolysis has been carried out in a divided cell equipped with an ordinary copper as working electrode, platinum mesh as the counter electrode and a SCE as the reference electrode. Ethanol and normal propyl alcohol were obtained. The current efficiency of CO2reduction is affected by various factors, such as step potential, step time, charge, the kinds of supporting electrolyte and so on.