Amino‐functionalized cellulose particles with a porous structure were prepared by a solvent‐releasing method with 1‐butyl‐3‐methylimdazolium chloride ([Bmim]Cl) followed by an amination reaction, and were incorporated with silica. The amino groups provided the base catalyst for the formation of silica on the porous structure during the in situ sol–gel reaction of tetraethyl orthosilicate. After the reaction, no free silica remained in the reaction medium. The microscopic morphologies (specific surface area, pore diameter, and pore volume) of the composite particles were affected by the silica content in the composites, which was controllable by the sol–gel reaction time. When silver nanoparticles were introduced to the pores of the cellulose particles by reduction of AgNO3 with amino groups, the composite exhibited catalytic ability and recyclability.