The secret in lunar soil: Oxygen and fuel may be produced on the moon
A recent paper in the international academic journal "Joule" has attracted widespread attention in the academic community.
After analyzing in detail the elements and mineral structures of the lunar soil retrieved by Chang'e-5 (hereinafter referred to as the Chang'e-5 lunar soil), the research team found that some active compounds in the lunar soil have good catalytic properties.
They used it as a catalyst to convert water and carbon dioxide into oxygen, hydrogen, methane, and methanol by using artificial photosynthesis technology with the help of simulated sunlight.
"Lunar soil is one of the most abundant resources on the moon. If lunar soil or lunar soil extracts can be used as artificial photosynthesis catalysts on the moon, the load and cost of spacecraft can be greatly reduced. In the future, materials may be obtained locally on the moon. Provide life support for astronauts and prepare fuel." On May 7, in an exclusive interview with a reporter from Science and Technology Daily, Yao Yingfang, the co-first author of the paper and a professor at Nanjing University, looked forward to it.
The elemental composition and micro-nano structure of lunar soil make it have good catalytic performance
In 2021, Nanjing University, as one of the joint team units led by the China Academy of Space Technology, obtained the first 1 gram of lunar samples released.
The scientific research team that published the results used 0.2 grams of it to conduct research and found some characteristics of lunar soil.
"Chang'e-5 lunar soil comes from very young basalt on the lunar surface. This mineral is rich in iron, titanium and other catalyst components commonly used in artificial photosynthesis. The team used machine learning and other methods to analyze the lunar soil structure many times and found that Among them, 8 crystalline minerals, such as ilmenite and titanium oxide, can exert good catalytic performance in artificial photosynthesis." Yao Yingfang said.
What is the actual catalytic performance of lunar soil?
The research team used lunar soil as a catalytic material for photovoltaic water electrolysis, photocatalytic water splitting, photocatalytic carbon dioxide reduction, and photothermal catalytic carbon dioxide hydrogenation. High performance and selectivity.
"In these experiments, we applied simulated sunlight, water and carbon dioxide as raw materials, and compared the lunar soil with the simulated lunar soil retrieved by the American Apollo program and the basalt on the earth's surface, and found that the three reacted in photovoltaic electrolysis of water. Among them, the Chang'e 5 lunar soil has the highest efficiency in producing oxygen and hydrogen. In the photothermal catalytic carbon dioxide hydrogenation reaction, the Chang'e 5 lunar soil produces methane and methanol more efficiently than other materials." Yao Yingfang said happily , Oxygen can provide life support for humans, methane is an active ingredient in rocket propellants, and methanol is a raw material for organic chemicals.
The study also found that the lunar soil surface is rich in micropores and vesicles. "This micro-nano structure further improves the catalytic performance of the lunar soil," said Yao Yingfang.
Will strive to carry the test in the future space program
Based on the above analysis, the research team proposes strategies and steps to realize extraterrestrial artificial photosynthesis using lunar soil for the lunar environment.
"Using the extremely low temperature of about -173 ℃ at night on the moon to condense and separate carbon dioxide from the air breathed by humans. Then, using sunlight, the Chang'e-5 lunar soil is used as an electrocatalyst for water splitting and a photothermal catalyst for carbon dioxide hydrogenation, Convert the waste gas exhaled by humans and the water resources exploited on the lunar surface into oxygen, hydrogen, methane and methanol." Yao Yingfang said that using extraterrestrial artificial photosynthesis technology, it may only need solar energy, water and lunar soil on the moon to produce Oxygen and hydrocarbons, the technology is expected to achieve low energy consumption and high-efficiency energy conversion with the help of the lunar surface temperature environment.
This provides a potential solution for establishing an in situ resource utilization system adapted to the extreme lunar environment.
Although the catalytic efficiency of the lunar soil is lower than that of the catalysts available on Earth, Yao Yingfang said that the research team will also separate and refine the effective catalytic components in the lunar soil to achieve better catalytic effects.
However, whether the extraterrestrial artificial photosynthesis technology can be realized in the real lunar environment needs further verification.
Yao Yingfang said that at present, they are working with researchers from the China Academy of Space Technology to try to implement extraterrestrial artificial photosynthesis technology in the future space program to carry out experiments and verify the real environment.