Mixed Perovskite Phases of BaTiO3/BaTi5O11 for Efficient Electrochemical Reduction of CO2 to CO.

Abstract

One of the most promising approaches in solving the energy crisis and reducing atmospheric CO₂ emissions is artificial photosynthetic CO₂ reduction. The electrochemical method for CO₂ reduction is more appealing since it can be operated under ambient conditions, and the product selectivity strongly depends on the applied potential. Perovskites with ferroelectric properties strongly adsorb linear CO₂ molecules. In this study, barium titanate (BaTiO₃) perovskite is used as an electrocatalyst to promote CO₂ activation and conversion to CO. Perovskite catalysts were prepared by ball-milling followed by annealing at 900 °C for 4 to 6 h in an open atmosphere. The TEM and SEM study shows that the particle size varies in the range of 80-200 nm. Mixed phases of BaTiO₃ and BaTi₅O₁₁ supported on nitrogen-doped carbon nanotubes are found to be highly active for electrocatalytic CO₂ reduction to CO with maximum Faradaic efficiency of 89.4 % at -1.0 V versus Ag/AgCl in CO₂ saturated 0.5 KOH solution. This study concludes that mixed phases of BaTiO₃ and BaTi₅O₁₁ are more active and highly selective for CO₂ conversion to CO compared to single-phase BaTiO₃.