Mesocrystals,the non-classical crystals with highly ordered nanopartide superstructures,have shown great potential in many applications because of their newly collective properties.However,there is still a lack of a facile and general synthesis strategy to organize and integrate distinct components into complex mesocrystals,and of reported application for them in industrial catalytic reactions.Herein we report a general bottom-up synthesis of CuO-based trimetallic oxide mesoaystals (denoted as CuO-M1Ox-M2O,where M1 and M2 =Zn,In,Fe,Ni,Mn,and Co) using a simple precipitation method followed by a hydrothermal treatment and a topotactic transformation via calcination.When these mesocrystals were used as the catalyst to produce trichlorosilane (TCS) via Si hydrochlorination reaction,they exhibited excellent catalytic performance with much increased Si conversion and TCS selectivity.In particular,the TCS yield was increased 19-fold than that of the catalyst-free process.The latter is the current industrial process.The efficiently catalytic property of these mesocrystals is attributed to the formation of well-defined nanoscale heterointerfaces that can effectively facilitate the charge transfer,and the generation of the compressive and tensile strain on CuO near the interfaces among different metal oxides.The synthetic approach developed here could be applicable to fabricate versatile complicated metal oxide mesocrystals as novel catalysts for various industrial chemical reactions.