Car methanol from air CO2 by temperature difference alone: the Chinese study

Source: HW Upgrade added 18th Jan 2021

A group of Chinese researchers showed in the laboratory the possibility of obtaining methanol, which can be used in cars as a fuel, starting from the CO2 in the air by exploiting simple temperature changes, using nanosurfaces of tungsten and bismuth perosvskite

by Roberto Colombo published 18 January 2021 , at 11: 01 in the Technology channel

The fossil fuels were the fundamental basis for the development of our society, but it has been shown that the pace at which we are burning is unsustainable for the planet . One of the key points is the reintroduction of large quantities of carbon dioxide into the atmosphere , trapped over millions of years in what are now gas and oil fields. Carbon dioxide acts as greenhouse gas and for the scientific community is the main responsible for global warming , the increase, of anthropogenic origin, of the average surface temperature of our planet.

As we said recently in a news published at the end of last year 2020, being able to transform CO2 itself into more complex hydrocarbons to be used as fuel is the holy grail that scientists are looking for today: this would allow us to have a neutral carbon cycle and not to introduce new quantities of carbon dioxide into the atmosphere . As we reported, Oxford University scientists have shown the feasibility of a method of converting CO2 into jet fuel, but many research groups are working on similar issues.

Methanol from CO2, by simple temperature difference

An interesting news comes from a group of Chinese researchers, who showed in the laboratory the possibility of obtaining methanol (CH3OH), which can be used easily in common car internal combustion engines as fuel, a starting from CO2 by exploiting simple temperature changes, using nanosurfaces perosvskite of tungsten and bismuth .

The study published in Nature Communications examines in detail the methods of production and characterization of compos based on tungsten and bismuth and the processes by which, in different cycles in which the temperature is made to vary, the nanosurfaces are able to transform carbon dioxide into methanol. Generally this process requires high temperatures and high pressures, but in the case of the research of Chinese scientists the procedure can be carried out in easily reachable temperature ranges in daily life.

Also is the temperature variation to supply the energy necessary for the process , which is therefore once fully operational, at no cost. It is therefore a class of materials defined as pyroelectric. Scientists analyzed process performance over different cycles and with different temperature ranges (15 ?? 40 ° C, 15 ?? 50 ° C, 15 ?? 70 ° C , 15 ?? 85 ° C), resulting in a methanol yield equal to 40. 0 µmol / g . The synthesis process is quite complex and sees the production of electrons and holes as a fundamental point and scientists have obtained the best yields in cases where a sacrificial agent (Na2SO3) has been introduced into the process, capable of avoiding recombination. of electrons and holes. The process of reducing carbon dioxide to methanol has also been shown to have excellent selectivity , with very low amounts of methane (CH4) and carbon monoxide (CO).

At the moment the process has been tested on a small scale, with 40 milligrams of Bi2WO6 powder suspended in 5 mL 0.2 M NaHCO3 in a container of 50 ml with the addition of 0.3 M of Na2SO3 and bubbling for 10 minutes high purity carbon dioxide in the liquid. The bottle was then sealed and exposed to heating and cooling cycles, in the temperature ranges that we reported in the previous paragraph. Finally the methanol yield was analyzed by taking one milliliter of solution by gas chromatography. At present, therefore, the research team has demonstrated the process of reducing CO2 to methanol, but further work will be needed to make the process available in daily life and on a large scale. However, the road traced seems promising.