Role of N-Rich Coordination Environment in Metal–Organic Frameworks for Enhanced Photocatalytic Dye Degradation

Two new crystalline metal–organic frameworks (MOFs) ZnPHTIA and ZnBPTIA were synthesized using Zn(II) metal salt and 5-triazole isophthalic acid (TIA) in the presence of coligands 1,10-phenanthroline (PH) and 4,4′-bipyridine (BP), respectively. Single-crystal structures revealed different types of Zn–N coordination environments and degrees of dimensionality in ZnPHTIA and ZnBPTIA structures. High numbers of Zn–N coordination in the extended structures of these MOFs acted as efficient photocatalysts for the degradation of methylene blue dye. High-resolution mass spectra, fluorescence, and ESR spectra measurements of the catalyst revealed that the OH· radicals are responsible for photodegradation. Photocatalytic efficiency of ZnPHTIA and ZnBPTIA was also compared with the noncoligand-based ZnTIA-1 framework. Among all, ZnPHTIA (98.2%) shows excellent catalytic efficiency compared with ZnBPTIA and ZnTIA-1.