高效Ag@AgBr等离子体光催化剂的制备及可见光活性研究

采用水热法和光致还原法制备了具有等离子体共振效应的Ag@AgBr可见光催化剂,利用XRD,SEM,EDX,DRS和XPS等手段对产物的结构和性能进行表征,并研究了催化剂在可见光下对罗丹明B(RhB)的光催化降解性能,考察了催化剂的循环使用及捕获剂对Ag@AgBr光催化性能的影响.结果表明:贵金属Ag纳米粒子的表面等离子体共振效应可显著增强Ag@AgBr对可见光的吸收;催化剂对罗丹明B具有较高的可见光降解活性和稳定性,在可见光下照射90 min,对罗丹明B的降解率达95%以上,光催化剂循环使用5次仍具有良好的光催化降解活性;淬灭实验表明在Ag@AgBr降解罗丹明B过程中,吸附在催化剂表面的h+、·OH、O2·-是主要的活性物种.

Preparation of Highly Efficient Ag@AgBr Plasmonic Photocatalyst and Its Photocatalytic Performance under Visible Light

A highly efficient and stable visible light driven Ag@AgBr plasmonic photocatalyst was successfully fabricated through a hydrothermal and subsequently photo-reduction method. The as prepared samples were characterized using XRD, SEM, EDX, DRS and XPS. The photocatalytic activities of the samples were evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. Recycling runs and scavengers were examined. The results show that the as-prepared Ag@AgBr plasmonic photocatalysts showed a strong absorption in visible light region, which attributes to the plasmon resonance of Ag NPs anchored on the surface of AgBr particles. The obtained Ag@AgBr photocatalyst showed excellent and stable photocatalytic performance for the degradation of RhB and more than 95% of RhB could be degradated in 90 min under visible light irradiation. Besides, after five recycled experiments the photocatalytic activity almost kept unchanged. The photodegradation was greatly suppressed by benzoquinone while slightly decreased by isopropanol and NaHCO3. The mechanism for the degradation of RhB by Ag@AgBr under visible light irradiation was discussed.