It has been a great challenge to develop an efficient and stable catalyst for dry reforming of methane with carbon dioxide. A new catalyst was synthesized with the catalytically active component in both the lattice and on the surface of the mesoporous support. A remarkable improvement in the catalytic performance of Ni nanocrystals assembled inside pore channels of mesostructured Ni-doped ceria was observed. The initial activity and long-term stability of the sample substantially surpassed that of samples without the intermixed oxide and/or a nonporous architecture, even though the latter was more available. Such an effect concerning a collaborative function stemming from a mesostructure and solid solution has been rarely reported previously in catalysis involving CeO₂. We believe that this finding might be of a very generic character and be extended to lots of similar fields. It is expected that the results here can spur experimental and theoretical investigation to promote fundamental comprehension of host–guest or metal–oxide interplay in CeO₂-based composite materials.