Controllable Synthesis Of Titanium Based Catalysts For Efficient CO₂ Reduction

With the increases concentration of carbon dioxide in the earth’s atmosphere,the environmental problems such as greenhouse effect and ocean acidification are becoming more and more serious.The gradual depletion of reserves as oil,natural gas resources and environmental pollution caused by large scale consumption of those resources have make an impact on the normal production and living activities of human beings.Therefore,we need to find new energy acquisition methods to reduce the impact on non-renewable energy dependence.Carbon monoxide,methane,methanol and other chemical intermediates are the products of carbon dioxide reduction or hydrogenation.Among various CO₂ reduction routes,reverse water-gas synthesis（RWGS）and CO₂ reduction to methanol are highly attractive.In this thesis,we have synthesized Pd/TiO₂ and TiO₂/In₂O₃ solid solution catalysts for the efficient CO₂reduction into syngas and methanol respectively.The catalytic performance has been optimized and the catalytic mechanism has been investigated.The main research contents of this thesis are as follows:（1）Pd/TiO₂ material has been prepared by a facile impregnation method and its catalytic performance has been enhanced by synthetic condition and composition optimization.The optimized Pd/TiO₂ material shows a CO₂ conversion rate of as high as 43%with an excellent selectivity towards CO（99%）at relatively mild reaction temperature（280℃）and under near ambient pressure.Even after 12 hours of continuous reaction,the conversion rate of carbon dioxide reduction to carbon monoxide still remains as high as 38%.（2）TiO₂/In₂O₃ solid solution catalyst has been prepared by a coprecipitation method and optimized by adjusting the ratio of titanium to indium.The optimized TiO₂/In₂O₃ shows high carbon dioxide reduction performance,especially,methanol can be obtained under high pressure.The selectivity of TiO₂/In₂O₃ for CO₂ reduction into CO or methanol relies on the ratio of In:Ti of obtained materials:At In:Ti=30:1,TiO₂/In₂O₃ shows the highest methanol performance;when In:Ti=1:20,the material shows the highest carbon monoxide output,and the CO output was 2.36mmol/50mgcat.