Catalytic cracking is a process in which hydrocarbon molecules undergo a catalytic reaction in the presence of an acidic solid catalyst, and the addition of a small amount of rare earth can significantly improve the activity and stability of the catalyst. At present, rare earth catalytic materials play an important role in petrochemical, fossil fuel catalytic combustion, automobile emission control, industrial waste gas purification, solid solution fuel cells, and other fields.
A molecular sieve is a synthetic hydrated aluminosilicate (zeolite) or natural zeolite, which is an essential active component in cracking catalysts. In industry, sodium-type molecular sieves are generally prepared by hydrothermal synthesis. Usually, the cation of molecular sieves prepared by the hydrothermal method is Na+, but in practical applications, Na+ is sometimes exchanged for light rare earth (La, Ce, Pr, etc.) ions, which makes the molecular sieves have affinity and is easy to exchange, and the exchanged molecular sieves have good structural stability and high activity.
The principle of exhaust gas purification is to oxidize and reduce harmful gases such as CO, HC, and NOx into harmless CO2, N2, and H2O gases under the action of catalysts. In the conversion process, there is a kind of catalyst that can catalyze and purify the above three kinds of harmful substances, which is called a three-way catalyst (TWC). The TWC consists of a catalyst carrier, an active coating, and active components (Pd, Pt, Rh, etc.). Adding rare earth oxides (such as CeO2, Y2O3, etc.) to the exhaust gas purification catalyst can improve the performance of the catalyst carrier, improve the catalyst activity, oxygen storage capacity, and anti-toxicity, and reduce the consumption of active components.
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