Highly homogeneous multicomponent mesoporous catalysts: Defective amorphous vs. nanocrystalline CeO2 structure towards CO-PROX reaction

Mesoporous multicomponent materials with uniform pore sizes and well-defined network
geometries are viewed as highly attractive candidates in the catalysis field. However, their
synthesis at a high homogeneity level is considered quite challenging. Herein, alumina
based mixed oxides (Al/Ce/Cu or Fe) are produced through a facile evaporation-induced-self-assembly route and tested towards preferential oxidation of CO in H2-rich gas. The
effect of several synthetic parameters is investigated, with citric acid addition identified as
a key factor in view of obtaining high mesoscopic order and notable homogeneity,
particularly at high dopant amounts. Following thermal aging at 900 C, metal oxides
distribution and nanoporous nature are well-preserved with a parallel nucleation of ceria
nanoparticles into the semi-crystalline inorganic framework. CO-PROX assessment of the aged samples reveals a drastic enhancement in catalytic activity, especially for the ternary
Cu-Ce-Al system, associated with material's structural reconstruction strongly affecting metal-support interaction.