Study On Photoelectrocatalytic Reduction Of Carbon Dioxide On The CuO Nanoparticles Composite Electrode

With the development of economy, the improvement of mankind energy demand year by year, the amount of carbon dioxide in atmosphere is increasing fiercely, CO 2 emissions may be about 42.3 billion tons by 2030. CO2 is the main greenhouse effect gases, one of the main factors in global warming. Therefore, how to mitigate the green house effect, decrease ing the content of CO2 in the atmosphere will be the urgent matter. however,CO2 is polar molecule, its carbon is the highest state, which has good chemical stability, and the resource recycling use of CO2 is very difficult, so reduction of CO2 is a challenging research work. Resource recycling use of CO2 mainly has these reaction paths: heterogeneous, homogeneous catalytic hydrogenation, catalytic copolymerization and photocatalytic reduction and electrocatalytic reduction. In the traditional methods, heterogeneous, homogeneous catalytic hydrogenation and catalytic copolymerization at high temperature and high pressure, the hydrogen derived from fossils, these paths had little obvious practical significance. However, the hydrogen is from H2 O in photocatalytic reduction and electrocatalytic reduction CO 2 process, these paths may take place under room temperature and atmospheric pressure, can be able to selectively generate small molecule compounds such as HCOOH, CO, CH4, C2H4 and CH3 OH.CuO is a narrow band semiconductor(1.84 eV), its capacitive arc value is small, with excel ent electrocatalytic activity as well as high selectivity for catalytic products.In this article, we have studied the photoelectric integration catalytic reduction of CO2 reduction with composite catalyst based on C uO NPs, which could be divided into three aspects as follows:1. Using CuO NPs as working electrode, CeO2 NPs were prepared by constant current electrodeposition, the CeO2/CuO NPs catalysis was obtained. After modified CeO2 NPs, from the UV- vis DRS of CeO2/CuO NPs, it can be clearly seen the visible light absorption enhanced obviously. The products outputs in the photoelectrocatalytic reduction of CO2 were examined by gas chromato graphy: the predominant product was methanol, the methanol concentration reached to 180.03 mmol·L-1·cm-2 when the reaction proceeds 6 h. Compared photoelectrocatalytic reduction with single photocatalytic reduction and single electrocatalytic reduction, the methanol output of photoelectrocatalytic reduction exceed summing up the value of the single photocatalytic reduction and single electrocatalytic reduction twofold.2. The Fe2O3 NPs were assembled to the CuO NPs by hydrothermal method, the Fe2O3/CuO NPs catalysis was obtained. It showed that the Fe2O3 NPs were sheet octahedral shape morphology and distributed on the C uO NPs surface uniformly according to the SEM testing. The Fe2O3/CuO NPs had large surface area and were beneficial for adsorbing CO2 to improve the concentration of the reactants, so could improved CO2 transformation efficiency. Measured by UV- vis DRS, it got the band gap of the as-prepared catalysis, 1.99 eV, it could be irradiated by the visible light shorter than 932 nm, which demonstrates it possesses greatly increased its utilization of the visible light. In the process of photoelectrocatalytic reduction CO2, the methanol field(67.23 mmol·L-1·cm-2) is 2 times than the sum of that in the single photocatalytic reduction and single electrocatalytic reduction, which indicates the distinct synergistic effect between electrocatalytic reduction and photocatalytic reduction.3. By using the method of pulse deposition, Ni/CuO NPs catalysis was obtained. After assembled N i, measured by UV- vis DRS, it got the band gap of the as-prepared catalysis, 1.95 eV, it also could be enhanced obviously in absorption of the visible light with wavelength 420 nm to 580 nm. It showed that the introduction of the N i had been greatly increased the absorption of visible light. In the process of photoelectrocatalytic reduction of O2, the methanol output(6 h reached 257.3 mmol·L-1·cm-2), it was more than 5 times than the summing up the value of the single photocatalytic reduction and single electrocatalytic reduction. Promotion effect of the distinct synergistic effect between electrocatalytic reduction and photocatalytic reduction had been confirmed once again.In this paper, three kinds of new type composite electrodes were prepared, and decided to apply these to the application of photoelectrocatalytic reduction CO2. These effective and environmental benign photoelectric coordination catalysts. The method of photoelectrocatalytic reduction of CO2 provides a new idea and direction for the study on the turning CO2 into wealth. In terms of low carbon alcohol preparation from CO2 reduction has certain instruction and the model significance.