Visible-light photocatalytic degradation of azo dyes in water by Ag3PO4: An unusual dependency between adsorption and the degradation rate on pH value
Visible-light photocatalytic degradation of azo dyes in water by Ag3PO4: An unusual dependency between adsorption and the degradation rate on pH value
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Ag3PO4 可见光光催化降解水中偶氮染料：吸附和降解速率对 pH 值的异常依赖性
DOI：
10.1016/j.molcata.2016.05.009
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发表时间：
2016-09-01
影响因子：
--
通讯作者：
Ma, Wanhong
中科院分区：
文献类型：
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作者：
Li, Ruiping;Song, Xianghua;Ma, Wanhong
Ag3PO4催化剂在可见光下降解不同pH水中刚果红（CR）的过程中，降解速率与吸附量呈不规则关系。CR对Ag3PO4的吸附效率随着初始溶液pH的增加而降低，降解效率随着初始溶液pH的增加而提高。这一现象明显不同于大多数催化剂在水溶液中对有机化合物进行多相光催化的常规光催化性能。另外用甲基橙（MO）、甲基红（MR）和橙II三种偶氮染料进一步证实了Ag3PO4/染料在不同溶液pH值下的吸附-降解关系。三种染料的吸附性能与CR相似，在低pH条件下均表现出较高的吸附性能，而在高pH条件下则表现出较低的降解效率。以Ag3PO4为可见光催化剂的偶氮染料的这种特殊吸附降解关系，与FTIR光谱和表面氟化法测定的Ag3PO4表面存在OH基团相关缺陷有关，说明这些缺陷对Ag3PO4在水溶液中的可见光催化作用起着重要作用。(C) 2016 Elsevier B.V.版权所有
During visible light photocatalytic degradation of Congo red (CR) in water at different pH values by Ag3PO4 catalyst, the process was found along an irregular dependency between the degradation rate and adsorption capacity. The adsorption efficiency of CR on Ag3PO4 decreased with increasing initial solution pH, whereas its degradation efficiency increased with increasing solution pH value. This phenomenon was significantly different from conventional photocatalytic properties of most catalysts for heterogeneous photocatalysis of organic compounds in aqueous solution. Three other azo dyes, i.e. Methyl orange (MO), Methyl red (MR) and Orange II, were used to further confirm such an adsorption-degradation relationship of Ag3PO4/dye at different pH value of solution. The tested three dyes behaved similar to CR, and they showed unexceptionally higher adsorption behavior and lower degradation efficiency at low pH value or vice versa at high pH value. This special adsorption-degradation relationship for azo dyes with Ag3PO4 as visible-light catalyst was correlated with the OH group-related defects present on Ag3PO4 surface as determined by FTIR spectroscopy and surface fluorination method, implying that the defects played an important role for the visible-light photocatalysis of Ag3PO4 in water solution. (C) 2016 Elsevier B.V. All rights reserved.