Improved visible light triggered photocatalytic activities of BiOCl photocatalysts via a synergistic effect of doping and heterojunction engineering

Abstract

To manipulate the photocatalytic activities of BiOCl photocatalysts, doping and heterojunction engineering are simultaneously adopted. Herein, the photocatalysts Sm³⁺-doped BiOCl and BiOCl:Sm³⁺@yg-C₃N₄ were designed, in which their phase structure, morphology, optical properties and photocatalytic activities were systematically discussed. Excited at 408 nm, red emissions are seen from Sm³⁺-doped BiOCl microplates and their intensities were impacted by doping content, reaching the maximum value when the Sm³⁺ content was 1 mol% and the involved concentration mechanism was dominated by quadrupole–quadrupole interaction. Through analyzing the degradation of TC, the visible light triggered photocatalytic behaviors of the resultant compounds were studied. Compared with BiOCl microplates, an improved TC removal ability was seen in Sm³⁺-doped BiOCl microplates and the products with a Sm³⁺ content of 0.5 mol% show the best performance. Moreover, through constructing the heterojunction with g-C₃N₄, the TC removal capacity was further enhanced and the BiOCl:Sm³⁺@60%g-C₃N₄ exhibits the optimal photocatalytic activity, which was also much better than that of the commercial SnO₂ and TiO₂. Accordingly, the ˙O₂⁻, h⁺ and ˙OH active species were proven to contribute to the involved visible light driven photocatalytic mechanism. Furthermore, the separation and recombination of photogenerated carries via the Z-scheme transfer process in the designed heterojunction composites, led to splendid photocatalytic properties. Additionally, it was verified that the TC solution treated with synthesized compounds was nontoxic toward plant growth. Our findings may propose an available route to regulate the photocatalytic performance of the visible light driven photocatalysts.