Highly efficient visible light photocatalytic reduction of CO 2 to Methanol by CuO@g-C 3 N 4 Nanocomposite Md Abdus Salam Shaik, Prof Amita Pathak Indian Institute of Technology, India Solar energy conversion to value-added chemical fuels through photocatalytic CO 2 reduction has received considerable attention due to the urgent demands to solve the problems arising from global warming and the shortage of fossil fuels.Substantial efforts have been therefore devoted to develop artificial photosynthetic CO 2 reduction systems, paying attention to both homogeneous and heterogeneous catalysis, as well as the hybrids of both systems. Generally, the hybrid systems where wide-bandgap semiconductor materials coupled with carbon based narrow band gap semiconductors such as graphene oxide (GO), carbon nanotube (CNT), graphene nitride (g-C 3 N 4 ) have been explored toward photocatalytic CO 2 reduction as they construct artificial Z-scheme photocatalytic systems. The systems can eventually eliminate the possibilities of high electron− hole recombination rates and low visible-light absorption, which often encountered in the in wide-bandgap semiconductors. However, constructing artificial Z-scheme photocatalysts by coupling a narrow band gap semiconductor metal oxide with a narrow band gap carbon based materials semiconductor can be a facile way to conquer these bottlenecks and demands a systematic investigation of their effect on photocatalytic efficacy. In view of this, narrow band gap P type CuO nanoparticle supported on graphitic carbon nitride (g-C 3 N 4 ) nanosheeets has been prepared by hydrothermal method. The photocatalytic performance of the g-C 3 N 4 @CuO composite material was evaluated through the reduction of CO 2 and methanol was formed as the predominant product analysed by gas chromatography. Details investigations of the materials were carried out by several microscopic and spectroscopic studies and it has been shown that the catalysis follows the Z-scheme pathway. The improved photocatalytic properties of g-C 3 N 4 @CuO compared to bared CuO and g-C 3 N 4 may be due to the formation of p-n heterojunctions between CuO and g-C 3 N 4 , resulting in the effective separation of photogenerated electron-hole pairs and the enhanced absorption of visible light. Furthermore, the g-C 3 N 4 @CuO composites had excellent stability and reused for five times without obvious loss of activity.
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