As compared with conventional nanocrystal systems, Cu-based mesocrystals have demonstrated distinct advantages in catalytic applications. Here, we report the preparation of a novel architectural Cu2O@CuO catalyst system integrated with the core/shell and mesocrystal structures (Cu2O@CuO MC) via a facile solvothermal process followed by calcination. The formation mechanism of the Cu2O@CuO MC with hexapod morphology was deciphered based on a series of time-dependent experiments and characterizations. When applied as a Cu-based catalyst to produce trichlorosilane (TCS) via Si hydrochlorination reaction, the Cu2O@CuO MC exhibited a much higher Si conversion, TCS selectivity, and stability than the catalyst-free industrial process and the Cu2O@CuO catalyst with a core-shell nanostructure. The enhanced catalytic efficiency of the former is attributed to the collective effects from its quite rough surface for providing abundant adsorption sites, the ordered nanoparticle arrangement in the core and shell for generating strong synergistic effects, and the micrometer size for the improved structural stability. This work demonstrates a practical route for designing sophisticated architectural structures that combine several structural functions within one catalyst system and their catalysis applications. (C) 2020 Elsevier Inc. All rights reserved.