Ordered heterogeneity of molecular photosensitizer toward enhanced photocatalysis

Ordered heterogeneity is significant for molecular photosensitizers to enhance their practical applications. However, the ordered heterogeneity of molecular photosensitizers is still a great challenge. In this article, we describe a supramolecular assembly method for the heterogeneity of molecular photosensitizers, with which a mononuclear Zn(II) molecular photosensitizer in solution was orderly assembled in long range via π–π stacking interactions, affording a cheap, solid photocatalyst (π-1) with a porous structure. With Co(II), Fe(III), or Ni(II) as a cocatalyst, π-1 shows noticeably better photocatalytic activity for CO(2) reduction than in a homogeneous system. The definite crystal structure and precise position of the catalytic center in π-1 were determined by single-crystal X-ray diffraction combined with X-ray diffraction adsorption spectra, based on which the enhanced activity of π-1 for photocatalytic CO(2) reduction was revealed by theoretical calculation. Thus, the reduced energy gap after ordered heterogeneity accelerates the electron transfer, greatly boosting the photocatalytic CO(2) reduction activity. This work demonstrates a method for developing crystalline, heterogeneous photocatalysts with definite structures and enhanced, catalytic performance.