Visible Light-Driven Highly Selective CO<sub>2</sub> Reduction to CH<sub>4</sub> Using Potassium-Doped g-C<sub>3</sub>N<sub>5</sub>
Bharati Debnath, Saideep Singh, Sk Mujaffar Hossain, Shrreya Krishnamurthy, Vivek Polshettiwar, Satishchandra Ogale
Abstract
Establishment of an efficient and robust artificial photocatalytic system to convert solar energy into chemical fuels through CO2 conversion is a cherished goal in the fields of clean energy and environmental protection. In this work, we have explored an emergent low-Z nitrogen-rich carbon nitride material g-C3N5 (analogue of g-C3N4) for CO2 conversion under visible light illumination. A significant enhancement of the CH4 production rate was detected for g-C3N5 in comparison to that of g-C3N4. Notably, g-C3N5 also showed a very impressive selectivity of 100% toward CH4 as compared to 21% for g-C3N4. The photocatalytic CO2 conversion was performed without using sacrificial reagents. We found that 1% K doping in g-C3N5 enhanced its performance even further without compromising the selectivity. Moreover, 1% K-doped g-C3N5 also exhibited better photostability than undoped g-C3N5. We have also employed density functional theory calculation-based analyses to understand and elucidate the possible reasons for the better photocatalytic performance of K-doped g-C3N5.