Air into Fuel :
After some intense research, scientists have finally demonstrated the direct conversion of CO2 to methanol (CH3OH) using a homogenous catalyst.
The study was led by G. K. Surya Prakash, a chemistry professor at the University of Southern California, along with the Nobel laureate George A. Olah, a distinguished professor at the University of Southern California. The researchers have published their paper on the CO2 to methanol conversion process in a recent issue of the Journal of the American Chemical Society.
“Direct CO2 capture and conversion to methanol using molecular hydrogen in the same pot was never achieved before,” lead researcher G. K. Surya Prakash, from the University of Southern California, told Phys.org. “We have now done it!”
The major breakthrough in the study was identifying the catalyst which speeds up the reaction and does not degrade at high temperature required for the process. Majority of the catalysts did not work beyond the formic acid stage. The catalyst, based on metal ruthenium, is a homogenous catalyst, i.e, it is in the same phase as CO2 and hydrogen reacts with. Due to this fact, CO2 does not need to be transformed after it is captured from the air and be simple added to Hydrogen gas. The catalyst can function at high temperature (decomposes at 155⁰C) and does not lose its efficiency. The catalyst can also reduce the carbamates or alkylammonium bicarbonates directly to methanol.
Air is bubbled through an aqueous solution of pentaethylenehexamine (PEHA), which is a polyamine and a catalyst is added to stimulate hydrogen to latch onto CO2(atmospheric- 400ppm) under pressure.
The solution is heated at high temperature (≈150⁰C), and around 79% of CO2 is converted to methanol. Methanol at this stage is mixed with water, which can be easily separated through simple distillation.
The reaction is as follows: