In-situ Synthesis Of CoPc/TiO₂ Photo-Catalyst And Study Of Photo-Catalysis Reduction Of CO₂

Along with the high speed development of industry, the earth ecological environment was broken severitly, among the biggest influence cause was "green house effect" that can induce the world to become warm. Science boundary was widespread to think, the main reason of "green house effect "creation is the greenhouse gas as CO₂ that mankind activity release emissions, the density of the greenhouse gas rapid arise in the atmosphere, so carbon dioxide recycling technique research be subjected to widespread of concern in recent years. Particularly the topic of carbon dioxide reduction technique got more extensive value, among them of Photocatalysis reduction became a new hot research. Currently photocatalyst reduction CO₂ was made use of UV-light in the organic melting agent, with low efficiency of reduction, high consume energy. So the topic aim was investigate a kind of new green technique that can Photocatalysis reduce CO₂ using visble light in the aqueous solution .A main research contents of Photocatalysis reduction CO₂ was choicing catalyst and making craft. Semi-conductor photocatalysts such as Titanium dioxide (TiO₂) cause extensive research of people as it has high Photocatalysis, no poisonous, low price and good stability. However, the band gap of TiO₂ is breadth (3.2eV),has high catalyst activity only making use of UV-light energy, only using 4% or so energy in the solar energy .Therefore, this experiment choose macrocyclic complex compound that was phthalocyanine cobalt(CoPc) to be activity species, which has good of heat stability, chemistry stability and photoelectric properties. And CoPc has strong absorbtion in visible light range(600-700 nm), using in-situ synthesize method in experiment can load phthalocyanine cobalt in the semi-conductor carrier of TiO₂ that has a property of photoreduction , preparing a kind of new photocatalyst with high catalysis activity and the width response range that can be used for reducing CO₂.In-situ chemistry synthesize was used as a new method in the process of preparing catalyst. In the synthesis process of the TiO₂ gel ,using 1,2-dicyanobenzene for raw materially tetraraacting to in-situ synthesis the phthalocyanine cobalt in the surface of TiO₂, got even distribution photocatalyst of the in-situ CoPc/TiO₂. With the efficiency of Photocatalysis reduction CO₂ was investigation index mark, investigating influence factor of preparing catalyst that was the CoPc charge number, pH value, the reaction time of in-situ synthesis and the roasting temperature of catalyst, the optimum condition of in-situ synthesis catalyst are as follows: The CoPc charge number is 3%;PH=1; 1,2-dicyanobenzene, Cobalt chloride and Titanic hydroxide buty add in together; The stirring time is 20 hours; The calcination temperature is 200℃. The in-situ CoPc/TiO₂ that prepared under the the best condition was used for reducing CO₂ under visble light, investigating the impact factor of Photocatalysis reaction, the superior condition of CO₂ Photocatalysis reaction are as follows :The use level of the in-situ CoPc/TiO₂ photocatalyst is 0.15g in the 100 mL, 0.1 mol/L NaOH ; The best electron donor is Na₂SO₃; The concentration of Na₂SO₃ is 0.1 mol/L; The time of irradiant reaction is 10 hours. After 10 h of the reaction, CO₂ was reduced to for the HCHO, CH₃OH, HCOOH, CO and CH₄. The total product can reach up to 2965.30μmol/g-catal..Applying the characterization of UV-Vis, DRS, FT-IR, XRD, BET, TG-DTA etc. verify in-situ synthesis CoPc that was successfully doped on the TiO₂ surface; The grain size of TiO₂ and the in-situ CoPc/TiO₂ are both the nanometer class, even distribute, better specific surface area. And the crystal type is main for the rutile phase. In this topic, the in-situ synthesis method of preparing photocatalyst was simple, fast and energy conservation; The in-situ CoPc/TiO₂ adoping in-situ synthesis can reduce CO₂ under visble light, openned widely light-absorbing range of the nanometer TiO₂, realization reducing CO₂ under visble light and in the aqueous solution. The reseach provided reference to make use of the solar energy for future, and a convenience cheap way to Photocatalysis reduction CO₂.