Strontium titanate for methane

In a new milestone in the search for better catalysts for making methane from CO2, Dr Pravin Ingole of IIT Delhi has developed a promising one: Chromium doped strontium titanate. His method is to coat the catalyst on a suitable substrate (special glass plates or gas-diffused electrodes), dip it in water and let carbon dioxide wash through the chamber in the presence of sunlight. The catalyst’s electrons absorb the light energy, become ‘excited’ and transfer from the ‘valance band’ to the ‘conduction band’, from where they are picked up by carbon dioxide. As this happens, water also splits into oxygen and hydrogen; the hydrogen joins hands with the carbon dioxide, becomes carboxyl, carbon monoxide and, finally, methane. Strontium titanate can act both as photo-cathode for carbon dioxide reduction and photo-anode for oxygen evolution from the same reactor, Dr Ingole told Quantum. A project to perfect the technology has been selected for financial support under the Indo-Hungarian Intergovernmental S&T Cooperation Programme.