A “supermaterial” of carbon… science when the Chinese kill two birds with one stone

Just type “carbon dioxide recycling” into a search engine for scientific research, “Google Scholar,” and you'll be greeted with dozens of success stories in which the heroes are researchers who succeeded in inventing a set of technologies. and methods aimed at reducing carbon emissions and creating sustainable pathways to use it as a valuable resource. Thus, it reduces its impact on climate change

While the techniques developed by the researchers seem promising, scientists are exploring more efficient, effective solutions based on cost, economic benefit and scalability, and Chinese researchers say they are one step closer to achieving a method. meets these conditions.

And in my published study Patrol In the Chinese Journal of Catalysts, Zhejiang University researchers described their method for converting carbon dioxide into dimethyl ether, an industrially important material, described as “superficial.”

The global dimethyl ether market size will reach US$6.6 billion by 2023, and the International Mining and Resources Conference expects the market to reach US$14.2 billion by 2032. An average 8.5% growth during the period 2024 to 2032. This is mainly due to the diversity of its applications, which are used in many industries, including:

• First: It is used in the manufacture of aerosol products such as hairspray, deodorants and spray paints.
• Secondly: It is used as a refrigerant in heat pump systems and air conditioning units, especially in countries where environmental regulations limit the use of conventional refrigerants, due to its high global warming potential.
• Third: It is used as a solvent in various industries, especially in extraction processes or as a detergent due to its solvent properties.
• Fourth: It is used as a raw material in the production of various chemicals, including olefins and dimethyl sulfate, which are used in the production of plastics, resins, and other chemicals.
• Fifth: Can be blended with liquefied petroleum gas (butane) to improve combustion characteristics and reduce emissions.
• Sixth: It can be used as a hydrogen carrier in fuel cell applications, making it useful for hydrogen-powered vehicles.

Two popular production methods

Apart from recycling carbon dioxide, this supermaterial is traditionally produced through two main processes:

• First: Conversion of methanol to dimethyl ether:
  The process begins with the production of synthetic gas (a mixture of carbon monoxide and hydrogen) from natural gas, coal, biomass or other hydrocarbon feedstocks. Once the synthetic gas is obtained, it is converted into methanol using catalysts. In the reaction process, using chemical-based catalysts, copper, methanol is further subjected to catalytic dehydration (a chemical process that removes water molecules from a compound using a catalyst), forming dimethyl ether.
• Second: Direct drying of methanol:
  This method is based on the production of dimethyl ether by direct drying. This method uses acidic catalysts such as zeolite to remove the water molecule from methanol, leading to the formation of the desired compound.

The choice between these methods often depends on factors such as available raw materials, cost, process efficiency, and environmental considerations. The indirect method via syngas is more common in large-scale industrial production, and due to its use of different raw materials, the direct methanol drying process is less common.

The third time… an added benefit

In the context of the global effort to reduce carbon dioxide emissions due to the negative effects of the climate, previous studies described several experiments to convert it into the supernatural substance “dimethyl ether”, thus “killing two birds with one stone is possible. Stone,” carbon emissions harmful to the Earth's climate are eliminated, on the other hand in various industries. produce a more useful product.In these experiences:

• Direct Hydrogenation: Scientists have done With experience Direct hydrogenation processes involving the catalytic reaction of carbon dioxide with hydrogen to produce dimethyl ether and several catalysts including copper-based catalysts and copper nanoparticles are used.
• Layer trigger: This includes Layer stimulation The carbon dioxide is first converted to methanol and then the methanol is condensed to dimethyl ether. Copper catalysts were used to synthesize the initial methanol, followed by acid catalysts such as zeolites to dehydrate and convert the methanol. Dimethyl ether.
• Dual Functional Catalysts: This method depends catalysts It combines acidic and metallic functions, exploring copper nanoparticles supported by acidic oxides and converting carbon dioxide into dimethyl ether.

These trials faced several challenges, including:

• As CO2 conversion rates increase, the challenges in achieving high selectivity of the desired material increase, resulting in reduced productivity and the formation of undesirable by-products such as hydrocarbons.
• Sintering or agglomeration of the catalyst nanoparticles occurred during the reaction, which reduced the durability and efficiency of the catalyst.

What did the Chinese do?

To address these challenges, Chinese researchers led by Professor Feng Shu Xiao and Professor Liang Wang from Zhejiang University have announced a highly efficient, cost-effective, economically beneficial and industrially scalable method.

The researchers presented Report A press release issued by the Chinese Academy of Sciences simplified their new method, which they agreed to build on their previous efforts. The following are highlights of what they achieved:

• Determination of Catalyst Restrictions: They examined precatalysts developed for the direct conversion of carbon dioxide to dimethyl ether and identified challenges facing the researchers, including low yields of the desired product and increased production of unwanted byproducts.
• Enhanced catalyst development: They addressed the challenges by developing an improved copper nanoparticle-based catalyst, loading the copper nanoparticles onto a hydrophobic silica support modified with gallium (a soft silver metal often used in various applications).
• Acidity and Dehydration: Gallium-modified silica provides moderate acidity, helping methanol dehydration while preventing excessive dehydration leading to the formation of hydrocarbons.
• To prevent catalytic converter failure: The hydrophobic surface of the catalyst effectively prevents the sintering of copper nanoparticles, a common problem caused by water and methanol, thus maintaining the durability and performance of the catalyst.
• Optimum reaction conditions: Under the specified reaction conditions (flow of 6 liters of product used in the reaction using the catalyst in one hour at 240 °C and 3 MPa pressure), the catalyst achieved a CO2 conversion rate of 9.7% with high selectivity. Dimethyl ether required 59.3%.
• Durability and Durability: During 100 hours of continuous testing, the catalyst showed stable and long-lasting performance, with no signs of performance degradation, better than that of conventional copper catalysts.

“These steps represent an innovative approach to develop an efficient and durable catalyst for the conversion of carbon dioxide to dimethyl ether, offering promising opportunities for efficient carbon recycling,” the researchers say in the press release.

A laboratory effort to test the expansion awaits

According to Dr. Mahmoud Abdel Hafiz, professor of chemical engineering at Egypt's New Valley University, these promising opportunities for recycling require more effort to demonstrate the scalability and application of the idea in the real world.

In a telephone interview with Al Jazeera Net, Abdel Hafeez said: “As seen in the study, the laboratory experiments are very encouraging, but the key challenge is to what extent the new catalyst can be developed on an industrial scale for widespread use in converting carbon dioxide into dimethyl ether.”

He explains that the expansion of the idea needs further development to reduce by-products such as carbon dioxide and hydrocarbons. Although the selectivity ratio (59.3%) for the desired dimethyl ether has been reached, the by-products still represent 40%. It is desirable to reduce these.

He adds, “The issue of safety must also be addressed, and it must answer the question: Are there any safety concerns during the expanded production of dimethyl ether from carbon dioxide?”