Multivariate Functionalization of UiO-66 for Photocatalytic Water Remediation

The fast-increasing interest in multivariate metal-organic frameworks (MTV-MOFs) has burgeoned due to the possibility to create synergetic functions and achieve performance significantly better than their simple sum. In this work, we explore the opportunities and the effects of multivariate functionalization of UiO-66 on diverse properties important for photocatalytic water remediation: hydrolytic stability, band gap energy, photoconduction, Cr^VI and Cr^III adsorption capacity and kinetics, and Cr^VI to Cr^III photoreduction efficiency. By developing (Zr)UiO66-NH₂-(OH)₂-NO₂ multivariate material based on the combination of
2-aminoterephthalate, 2,5-dihydroxyterephthalate and 2-nitroterephthalate organic linkers in the same framework, we developed a dual sorbent/photo-catalyst for water remediation with excellent properties: (1) enhanced adsorption efficiency of Cr^VI and Cr^III ions; (2) improved photocatalytic conversion of Cr^VI to Cr^III; and (3) with suitable chemical stability under acidic conditions for the catalytic application. This work represents a milestone for an emerging class of reticular materials that can synergistically use the properties of individual functionalities to solve complex problems beyond just the water remediation application discussed in this paper.