Abstract:
Core-shell like Ag
2CO
3@AgBr composite photocatalyst was fabricated by the successive precipitation method. The obtained AgBr, Ag
2CO
3, Ag
2CO
3@AgBr samples were well characterized by N
2 physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra, and photocurrent test. The effects of AgBr shell on the texture, light absorption, photocurrent response and photocatalytic performance for main Ag
2CO
3 photocatalyst were investigated. The results showed that Ag
2CO
3@AgBr composite displayed much stronger and broader visible light absorption than pure AgBr and Ag
2CO
3. A distinct increase in both surface area and photocurrent density for Ag
2CO
3@AgBr was observed. Under visible light (400 nm < λ < 660 nm) irradiation, the photocatalytic activity test in degradation of methyl orange (MO) dye showed that Ag
2CO
3@AgBr showed excellent photocatalytic activity and the degradation rate constant over Ag
2CO
3@AgBr (0.209 min
-1) was 14 times higher than that of Ag
2CO
3 (0.0136 min
-1), 10 times faster than that of AgBr (0.0180 min
-1). Moreover, in recycling photoactivity tests, AgBr and Ag
2CO
3 fast lost the activity, but high stabilty was obtained over Ag
2CO
3@AgBr. Between the AgBr shell and Ag
2CO
3 core, the produced intimate Ag
2CO
3/AgBr interface with matched band-gap structure largely promoted the transfer of photogenerated electrons and holes. Moreover, the AgBr shell could effectively inhibit the dissolution of Ag
2CO
3 in aqueous solution, resulting in extremely high stability.