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 pi-pi stacking interactions, affording a cheap, solid photocatalyst (pi-1) with a porous structure. With Co(II), Fe(III), or Ni(II) as a cocatalyst, pi-1 shows noticeably better photo catalytic activity for CO2 reduction than in a homogeneous system. The definite crystal structure and precise position of the catalytic center in pi-1 were determined by single crystal X-ray diffraction combined with X-ray diffraction adsorption spectra, based on which the enhanced activity of pi-1 for photocatalytic CO2 reduction was revealed by theoretical calculation. Thus, the reduced energy gap after ordered heterogeneity accelerates the electron transfer, greatly boosting the photocatalytic CO2 reduction activity. This work demonstrates a method for developing crystalline, heterogeneous photocatalysts with definite structures and enhanced, catalytic performance.