Synthesis And Properties Of Basic Bismuth Nitrate Photocatalyst By Solid-state Grinding

Photocatalytic technology is one of the main methods to solve environmental pollution and energy shortage issues.The development of highly efficient photocatalysts plays the most important role in the industrialization of photocatalytic technology.Bismuth-based photocatalysts have attracted much attention because of their low toxicity,low price and abundant output.Among them,basic bismuth nitrate is also used as photocatalyst due to its abundant crystal structure and variety.In this paper,basic bismuth nitrate（Bi₆O₅（OH）₃（NO₃）₅·3H₂O）（denoted as BBN-5N）with highly exposed（110）facets,Bi₆O₅（OH）₃（NO₃）₅·3H₂O-Bi OI（denoted as BBN-Bi OI）heterojunction and Bi/Bi₆O₅（OH）₃（NO₃）₅·3H₂O（denoted as Bi/BBN）composite were synthesized through grinding-assisted at room temperature with Bi（NO₃）₃·5H₂O as bismuth source,and their photocatalytic properties were studied.The specific contensts are as follows:（1）BBN-5N was synthesized by a grinding-assistant room temperature reaction route,and Bi₆O₆（OH）₂（NO₃）₄·2H₂O（denoted as BBN-4N）was prepared by tuning Na OH amounts.Among them,the plate-like BBN-5N prepared at Na OH/Bi molar ratio of 2.13（denoted as BBN-5N-2.13）exhibited excellent photocatalytic activity and good photochemical and structural stability for malachite green(MG,10 mg L^-1)and methylene violet(MV,10 mg L^-1)degradation under UV light illumination due to its high surface area and high proportion of exposure（110）crystal surface.（2）In order to improve the visible-light photocatalytic performance of BBN,BBN-Bi OI heterojunction was synthesized by a grinding-assistant in-situ ion-exchange strategy.When the molar ratio of I^-/Bi³⁺was 0.8,BBN-Bi OI exhibited the premium visible light photocatalytic activity for MG(20 mg L^-1)degradation.This is because the in-situ growth of Bi OI nanoparticles on the surface of BBN expands the visible-light absorption and improves the carrier separation efficiency.（3）In view of the surface plasmon resonance（SPR）of base metal Bi,Bi/BBN composite was prepared by solid-state grinding and liquid reduction method.Among them,Bi/BBN prepared with thiourea（TU）as reducing agent showed good photodegradation activity under visible-light.This is mainly because the SPR of metal Bi improves the absorption ability of visible-light and the separation efficiency of photogenerated electrons and holes,thereby improving the photocatalytic activity of Bi/BBN.