pH调节剂对BiOCl结构和光催化降解RhB的影响

以水解法合成了BiOCl纳米片,并考察了制备溶液的pH调节剂对BiOCl晶形、形貌、孔径分布和比表面积、化学组成、光学性质及催化性能的影响.采用X射线衍射谱(XRD)、扫描电子显微镜(SEM)、N_2吸附、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(DRS)对所合成的BiOCl样品进行表征.表征和催化结果表明:pH调节剂为NaOH和Na_2CO_3的BiOCl样品含有杂质,pH调节剂为NH_4OH的BiOCl为纯四方晶型材料;3种pH调节剂合成出的BiOCl都为纳米片,纳米片粒子大小顺序为Na_2CO_3NH_4OHNaOH,孔径大小顺序为Na_2CO_3NaOHNH_4OH;以NaOH、Na_2CO_3、NH_4OH为pH调节剂合成出的BiOCl的带隙能分别为3.27、3.21、3.15 e V,表面元素均为B~(3+)、O~(2-)和Cl~-;可见光降解罗丹明B的顺序为NH_4OHNa_2CO_3NaOH.并且,我们阐述了pH调节剂对光催化降解RhB的影响机理.

Effect of pH regulators on structural performance and photocatalytic degradation of RhB over BiOCl samples

The BiOCl nanoplates were prepared by hydrolysis method.The influences of pH regulators on their crystalline phase,morphology,pore distribution and BET,chemical composition,optical property and photocataly-tic efficiency were studied by XRD,SEM,N2 adsorption-desorption,XPS,DRS and RhB photo-degradation under visible-light irradiation.Some impurities were discovered over BiOCl samples using NaOH and Na2 CO3 as pH regu-lators,which were different from the sample using NH4 OH as pH regulator.All the as-prepared BiOCl samples were nanoplates.The order of nanoplate diameter was Na2 CO3>NH4 OH>NaOH,and the order of pore size was Na2 CO3>NH4 OH>NaOH.In addition,the gap energies of BiOCl samples using NaOH,Na2 CO3 and NH4 OH as pH regulator were 3.27,3.21,3.15 eV,respectively.Elements of these obtained BiOCl samples were B3+、O2- and Cl-.The order of RhB degradation was NH4 OH>Na2 CO3>NaOH.Moreover,the mechanism of effect of pH regula-tors on RhB degradation was discussed in this paper.