Cu2O mesoporous spheres with a high internal diffusion capacity and improved catalytic ability for the aza-Henry reaction driven by visible light.

Mesoporous Cu2O spheres with a large pore size (LP-Cu2O) bring out a better performance towards the photocatalytic aza-Henry reaction than Cu2O spheres with a small pore size (SP-Cu2O). This work highlights the internal diffusion coefficient as a critical parameter for the fabrication of porous photocatalysts.