Aerogel-Like Composite Catalysts Synthesized via Advanced Approaches Combining Sol-Gel and SCF Methods
Доклады на конференциях
SCF technologies are proven to be an efficient tool for the synthesis of various functional materials possessing unique properties. At the same time, the number of method for the synthesis of the real industrial catalysts based on SCF is rather limited despite the combination of SCF properties allow one to obtain catalysts displaying unique selectivity and activity in a number of processes .
The efficiency of heterogeneous catalysts is largely determined by the support (matrix), which provides dispersion, stability and accessibility of the active phase. Aerogel based materials are promising candidates to immobilize active phase due to their high specific surface area and open pore structure . Developing the aerogel based catalyst it is necessary to remember that viable catalytic processes implies the solution of many problems including not just high activity, but also selectivity, mass and heat transfer issue, the stability of the active phase, morphology of the matrix and many others. In this regards only the comprehensive analysis of the properties of aerogel-like composite catalysts can give us a new ‘brand’.
Here we report the original approaches to synthesize the aerogel-like composite catalysts based on alumina and silica as a matrix. Using Ni-Cu system as an example it is shown that the silica framework formed in SC CO2 conditions allows one to synthesize the active catalysts with highly dispersed (few nanometers) active bimetallic phase without phase separation [3,4]. The oxide matrix prevents the sintering of metal particles, increases the dispersion and specific surface area, as well as accessibility of active phase. Also the novel approach for the synthesis of silica aerogel composites via sol-gel method and subsequent drying in SC CO2 creates the great potential to use a wide range of MOFs in continuous flow catalysis  and separation processes .
The work was performed with the support of the Russian Foundation for Basic Research (project 18-29-06022).