Preparation and application of rare earth modified catalyst for hydrogen production through ammonia decomposition

Abstract

The invention relates to the technical field of hydrogen production, in particular to preparation and application of a rare earth modified catalyst for hydrogen production through ammonia decomposition. According to the invention, yttrium and potassium are used as auxiliaries of the catalyst, and gamma-alumina is used as a carrier and is matched with yttrium and potassium, so that the usage amount of ruthenium is reduced, and high conversion rate of ammonia gas can still be ensured at a low temperature (430 DEG C). Due to low decomposition temperature, the problem of high energy consumption of ammonia decomposition at present is effectively relieved, in addition, due to the existence of rare earth element yttrium, H2 poisoning on ruthenium is effectively inhibited, and apparent activation energy is reduced. The preparation method is simple and easy to implement, the prepared catalyst is high in catalytic activity, the cost is lower than that of other ruthenium-based catalysts, and the reaction temperature of ammonia decomposition can be reduced to 430 DEG C. In a word, the catalyst is a novel ammonia decomposition catalyst and has a good industrial application prospect.

Description

technical field [0001] The invention relates to the technical field of hydrogen production, in particular to the preparation and application of a rare earth modified catalyst for ammonia decomposition to produce hydrogen. Background technique [0002] Hydrogen is the most abundant element on earth. Hydrogen comes from a wide range of sources. It can be obtained from various fossil fuels through hydrogen reformation or hydrogen production through ammonia cracking, and can also be produced through water electrolysis. Because the combustion product of hydrogen is water, it will not pollute the environment, so it is regarded as a clean energy with great application prospects. In addition to direct combustion of hydrogen, hydrogen is also widely used in fuel cells to generate electricity to drive cars, and the process does not produce any CO X and NO X . Since hydrogen fuel cells can efficiently convert chemical energy into electrical energy, they are considered to be a promis...

AI Technical Summary

Problems solved by technology

[0009] Patent document CN 111215063 A discloses the application of a metal catalyst supported by a rare earth carbonate as a carrier precursor in the ammonia decomposition reaction. Example 6 of the technical solution discloses that at a temperature of 450°C, the ammonia conversion rate is 97.5%, but the loading of ruthenium is 5%, and the content of yttrium reaches more than about 30%, the cost of the catalyst is relatively high; and the catalyst needs to use cerium carbonate as the carrier precursor, and the catalyst made of cerium oxide supported ruthenium

In short, its preparation process is complicated, the process has uncontrollable factors, and the preparation process also involves certain carbon emissions, which may not meet the requirements of existing environmental policies, and there are certain restrictions on its use; in addition, the price (cost) of cerium oxide is relatively high. High, 3-5 times that of alumina, resulting in higher catalyst cost, and the porosity and high temperature stability of cerium oxide are not as good as alumina (with certain restrictions)

[0010] In summary, there is no real low-cost catalyst with high activity and high stability that can completely decompose ammonia into hydrogen at a relatively low temperature. Therefore, it is necessary to seek and develop new ammonia decomposition catalysts. It is of great significance to promote the development of ammonia decomposition hydrogen production technology, especially the promotion of fuel cell technology

Images