A method for producing oxygen by electrolysis of carbon dioxide

Abstract

A method for preparing oxygen by electrolyzing carbon dioxide, which belongs to the field of electrochemical technology, is carried out according to the following steps: (1) mix anhydrous LiF and Li2CO3 in a molar ratio (0.5-1.5): 1 to obtain a mixed material; Add additives to the mixed material and mix evenly to make electrolyte molten salt; (3) Put the electrolyte molten salt in the electrolytic cell, heat it to 690~700°C, then pass CO2 gas into the electrolyte molten salt, and use Ni electrode Or the Ti electrode is used as the cathode, and the Pt electrode, Fe-Ni alloy electrode or Fe-Ni-Al2O3 alloy electrode is used as the anode, and the electrolyte molten salt is energized for electrolysis; oxygen is generated at the anode. The method of the invention uses molten salt to absorb carbon dioxide to perform electrolysis, and the molten salt system has high electrical conductivity, long electrode life, convenient operation, and environmental friendliness; and the prepared oxygen has high purity.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, in particular to a method for preparing oxygen by electrolyzing carbon dioxide. Background technique [0002] CO 2 It is an abundant carbon resource in nature, and it is the final product of the combustion of carbon-containing compounds; in the industrial production process of thermal power, cement, steel and ammonia, etc., a large amount of CO is produced 2 Most of them are directly discharged into the atmosphere and cannot be well used. According to statistics, CO in the atmosphere 2 Emissions increased from 4 billion tons per year in 1925 to 34 billion tons in 2011, and CO in the atmosphere 2 The cumulative amount is increasing at a rate of 4% per year; the global average CO per second in 2012 2 Discharge is 1100 tons. current atmospheric CO 2 The concentration is about 350ug / g, and by 2030 the atmospheric CO 2 The content of CO2 will reach 560ug / g, which will cause the average...

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Problems solved by technology

current atmospheric CO 2 The concentration is about 350ug / g, and by 2030 the atmospheric CO 2 The content of CO2 will reach 560ug / g, which will cause the average temperature of the earth to rise by 1.5~4.5℃; as the main greenhouse effect gas CO 2 , its large amount of emissions is seriously damaging the ecological environment of the earth, affecting the living environment of human beings, and wasting precious carbon resources. Its impact and harm have attracted widespread attention from all over the world

[0003] CO 2 It is a non-polar linear molecule, which is the highest oxidation state of carbon; due to CO 2 The thermal stability is very high, the chemical properties are stable, and the stable CO 2 It is very difficult to recycle; photocatalytic CO in aqueous solution 2 Reduction to CO, CH 4 , HCOOH, CH 3 Carbon-containing products such as OH, which face the electrode potential is too high, usually need a catalyst to reduce CO 2 The overvoltage required for the conversion, and the photoelectric catalytic conversion efficiency is low, the reaction rate is low, and the reaction energy consumption is large; most studies have shown that the catalyst activity and selectivity are still unsatisfactory, and there are bottlenecks in various conversion technologies and problems that need key breakthroughs waiting for solution

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