A Cu(II)-tetra(imidazole) coordination polymer and its g-C3N4 composite of photodegradation of organic dyes

Abstract

A Cu(II) coordination polymer {[Cu(tmpe)0.5(1,2-bdc)]·2CH3CN}n (Cu(tmpe)) (tmpe ​= ​1,1,2,2-tetra[4-(2-methyl-1H-imidazole-1-yl)phenyl]ethylene, 1,2-bdc ​= ​1,2-benzenedicarboxylate) was prepared. Cu(tmpe) has the (4,4)-connected 2D structure exhibiting the kgm topology (32·62·72)2. The series of attached g-C3N4 composites Cu(tmpe)/g-C3N4 were prepared with grinding method and the morphology, functional groups, chemical composition, thermal stability, band gap, optical properties and electrochemical performances of prepared materials were comprehensively characterized with XRD, SEM, HRTEM, EDX, FTIR, XPS, TGA, UV–Vis, PL and electrochemical tests. Cu(tmpe)/10%g-C3N4 had the highest catalytic efficiency for degradation of methylene blue (MB) in a series of Cu(tmpe)/wt%g-C3N4 (w ​= ​5, 10, 15, 20). The photocatalytic study of Cu(tmpe) and its composite Cu(tmpe)/10%g-C3N4 showed high efficiencies of decomposition methylene blue (MB), methyl orange (MO), methyl violet (MV), and rhodamine B (RhB) with the rates were in the order of MB ​> ​MO ​> ​MV ​> ​RhB. Cu(tmpe) and Cu(tmpe)/10%g-C3N4 could degrade 95.4% and 93.6% of MB after 60 ​min and 30 ​min, respectively. The photocatalytic possible mechanism of the degradation process was studied with trapping experiments as well as Mott-Schottky tests. Cu(tmpe) and Cu(tmpe)/10%g-C3N4 composite are good photocatalytic materials for removing organic dye pollutants from wastewater.