Executive Summary : | Renewable and sustainable energy sources are required as a consequence of the environmental issues associated with the continued use of fossil fuels. Mankind releases about 39Gt carbon dioxide (CO2) per year into the earth’s atmosphere where it acts as a greenhouse gas. The chemical transformation of CO2 into valuable chemical feedstock becomes increasingly important, as the concentration of CO2 in the atmosphere has reached 400 ppm. This is now the utmost necessity to develop new renewable energy sources based on carbon dioxide activation and utilization. Non-precious as well as environmentally benign transition metal-catalyzed activation of CO2 can provide methanol and methane through formic acid intermediate. Formic acid (HCO2H; 4.4 wt% H2) and methanol (12.6 wt% H2) have emerged as chemical storage of hydrogen in liquid form. In addition, methanol (MeOH) could be a direct replacement for gasoline and as a fuel cell input. Furthermore, MeOH can be utilised as a source for the formation of carbon-carbon, carbon-nitrogen, and carbon-oxygen bonds which are the important motifs found in a large number of natural products as well as fine and bulk chemicals. Renewable and sustainable energy generation (MeOH and CH4) and hydrogen storage through utilisation of CO2 can significantly attribute to decarbonization and pollution minimization; thus, this approach could provide four-fold benefits. It is indispensable to investigate the production of HCO2H and CH3OH through first-row transition metal-catalyzed CO2 activation. Over the past several decades, precious transition metal catalysts have been applied for the conversion of CO2 into fine chemicals because of their efficient and reversible two electron redox processes. Recent progress includes the use of ligand-centered processes as alternatives to the metal-centered redox cycles, in which the redox processes are highly controllable by designing the redox-active supporting ligands. This project comprises the synthesis of monometallic as well as multimetallic clusters of early transition metals with redox active ligands. The low valent early transition metals have potentially a strong reducing ability towards carbon dioxide. This process could be the most viable method to provide an economic, environmentally benign and sustainable solution for future generations. Investigators also anticipate the large-scale implementation by extending our idea to heterogeneous graphene-conjugated catalysts. The aforesaid device would efficiently deliver the industry-scale production. |
Co-PI: | Dr Amol A Kulkarni, Scientist, CSIR-National Chemical Laboratory (NCL), Pune, Dr Vidya Dnyaneshwar Avasare, Professor, Sir Parashurambhau College, Pune, Prof. G K Lahiri, Dr Debabrata Maiti, Associate Editor, Indian Institute of Technology (IIT) Bombay |
Total Budget (INR): | 2,32,39,600 |
Achievements : | 1. Through extensive literature surveys, transition metal catalysts with pincer ligands are very good for CO2 hydrogenation. Similar studies of pincer ligands with early transition metals are not yet done.
2. The eight pincer ligands, which have great promise, have been synthesized. Metal complexes with two different types of pincer ligands having pyridine and amine linkers have great promise. Since it is known that the methyl version of these ligands can give entirely different properties, they are also taken into account. The protocols for the syntheses of these 8 ligands are briefly explained in the report. |
