Since the discovery of sodium nitrate deposit in Chile, South America in 1809, Chilean saltpeter quickly became the main source of inorganic minerals containing nitrogen fertilizer in the world at that time. It is estimated that during the period of 1850- 1900, 70% of the inorganic nitrogen fertilizer in the world came from Chilean saltpeter, but the mineral resources were limited, which forced people to think about how to make the atmosphere free. Artificial transformation into compound nitrogen that can be absorbed by plants, that is, artificial nitrogen fixation, has always been an important topic for chemists to explore, especially how to directly synthesize ammonia by using nitrogen in the air and hydrogen in the water, which has always been one of the focuses of chemists in the19th century. However, due to long-term failure, some people have come to the wrong conclusion that it is impossible to directly synthesize ammonia from nitrogen and hydrogen. Until 1909, the German chemical Hubble made a breakthrough, and successfully established a device that could produce 80g ammonia per hour, which made people see the dawn of solving this problem and created the history of synthetic ammonia, and Hubble won the Nobel Prize in chemistry of 19 18.