The invention discloses a 
core shell catalyst by taking 
hydrotalcite as a shell and a 
molecular sieve as a core as well as a preparation and an application thereof. According to the invention, 
divalent metal source and aluminum species in a core-shell 
molecular sieve are used for forming a 
hydrotalcite compound on the surface of the 
molecular sieve, and the core-shell structure molecular 
sieve by taking the molecular 
sieve as the core and the 
petal hydrotalcite as the shell is formed; after the molecular 
sieve is reduced, the nano-grade 
metal-modified molecular sieve catalyst having 
uniform size, high dispersibility, excellent 
heat stability and high universality is obtained, and can be used for a catalytic reaction for hydrogenation synthesis of m-
dinitrobenzene to obtain m-phenylenediamine. compared with the prior art, the preparation process is simple, the 
metal atom 
utilization rate is high, applied metal source is almost completely reacted, no loss is generated, cost is reduced, and 
pollution on environment is reduced, industrial production is easy, and a series of different metal-modified molecular sieve catalysts can be prepared according to the modifiable character of the composition elements of the hydrotalcite and diversity of a topological structure of the molecular sieve.