One-pot combustion synthesis and efficient broad spectrum photoactivity of Bi/BiOBr:Yb,Er/C photocatalyst

A highly efficient broad spectrum responsive Bi/BiOBr:Yb,Er/C ternary composite was synthesized by a simple one-pot combustion method using nitrates and citric acid as raw materials. Experimental results show that Er3+/Yb3+ were successfully doped into BiOBr lattice, and metallic Bi nanoparticles and carbon species were formed simultaneously. Compared with pure BiOBr and Bi/BiOBr/C, as-synthesized Bi/BiOBr:Yb,Er/C ternary photocatalyst is highly responsive in the UV-visible-NIR range, and possesses the best photodegradation performance for Rhodamine B, phenol, and imidacloprid under visible, NIR, or solar light irradiation, which can be attributed to the synergetic effects of surface plasma resonance of metallic Bi, up-conversion transition of Er3+ and heterojunctions (Bi/BiOBr, Bi/C, and BiOBr/C). Moreover, a plausible mechanism was given, the main active species, and photostability of samples were studied. The solar light photoactivity and influences of pH value and anions (Cl-, SO42-, CO32-, HCO3-, and NO3-) were also investigated. This study highlights the advantages of synergetic effects of SPR, up-conversion and heterojunctions, which provides a useful guide toward the rational design of broad spectrum (UV-visible-near infrared) photocatalysts.