Facile fabrication of ZnPc sensitized g-C₃N₄ through ball milling method toward an enhanced photocatalytic property

Ball milling (BM) is utilized to fabricate a composite photocatalyst composed of g-C3N4 material and ZnPc, which traditionally has been a sensitizer in TiO2 based solar cells yet usually having severe agglomeration problem. X-ray diffraction and FTIR results demonstrate that ZnPc has been immobilized onto g-C3N4 surfaces and that the inter-molecular bonds were also destroyed to a large extent, leading to improved dispersion of ZnPc. Further diffuse reflectance and photoluminescence characterization indicated distinct extended spectral response region at 600–700 nm as well as prohibited carrier recombination of the g-C3N4/ZnPc composite. When utilized as a photocatalyst, the properties of g-C3N4/ZnPc composites in the degradation of RhB were 3.1, 1.8 and 4.3 times higher than those of the pristine, ball-milled pure g-C3N4 and g-C3N4&ZnPc. By adding some scavengers, the main active species involved in the photocatalytic process were identified as •O2−. The improved photocatalytic performance could be ascribed to well-matched band gaps between ZnPc and g-C3N4, extended light-responsive range as well as the better ZnPc dispersion upon g-C3N4 surfaces.