Ordered heterogeneity of molecular photosensitizer toward enhanced photocatalysis

Abstract

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 CO2reduction 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 CO2reduction was revealed by theoretical calculation. Thus, the reduced energy gap after ordered heterogeneity accelerates the electron transfer, greatly boosting the photocatalytic CO2reduction activity. This work demonstrates a method for developing crystalline, heterogeneous photocatalysts with definite structures and enhanced, catalytic performance.