Abstract
Solar conversions of water to hydrogen and carbon dioxide to hydrocarbon fuels are the two attractive options to reduce global warming and generation of sustainable energy.The mission for utilization of the sunlight to the maximum extent for these purposes has provided motivation to find efficient materials.In the present study,we have systematically investigated the electronic structure of Co-doped TiO2 with anatase crystal structure to explain the experimentally observed photocatalytic activity and to explore the limiting factors.The present study revealed the preferred charge state for Co to achieve the best photoconversion efficiency.We have also investigated the role of lattice defects in the photoactivity of Co-doped TiO2.Motivated by experimental observation,we have investigated the role of codoping of B/N/V into Co-doped TiO2.For this purpose,we have employed a more reliable hybrid density functional.To further enhance the photoactivity,we have proposed codoping with(F/Sb/Nb/Ta/Cr/Mo/W) into Co-doped TiO2.We have checked the feasibility of doping by calculating the defect formation energy.Interestingly,codoping with(F/Sb/V/Nb/Ta) successfully overcomes the limitations of Co-doped TiO2.Finally,eligibility of these materials toward water splitting and CO2 conversion is checked by aligning the band edges with respect to water and CO,redox levels.By considering all these factors,the present study was carried out to find out the best choice of the dopant pair to enhance the photocatalytic activity for TiO2 under sunlight.
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