摘要
以KCl、Bi(NO3)3和类石墨氮化碳(g-C_3N_4)为前体,采用水热法成功制备了Bi OCl/g-C_3N_4异质结光催化剂,并进行可见光催化还原CO_2,考察了催化剂的活性及稳定性,同时研究BiOCl:g-C_3N_4(摩尔比)、催化剂用量和光照强度对光催化还原CO_2的影响。结果表明,在水蒸气的存在下,Bi OCl/g-C_3N_4较纯BiOCl和g-C_3N_4具有更高的光催化还原CO_2活性,在催化剂用量为0.1 g,光照强度为2.413×10-6 einstein·min-1·cm-2,Bi OCl:g-C_3N_4摩尔比为1:1的异质结催化剂显示了最高的光催化还原CO_2活性,且可见光催化剂在5次套用实验后其活性基本不变。基于X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、比表面积测试(BET)和紫外-可见(UV-vis)吸收光谱表征,可以推断Bi OCl和g-C_3N_4之间形成的p-n结能有效分离光生电子和空穴,是增强光催化剂活性的主要原因。
Bi OCl/g-C3N4 heterojunction catalyst was synthesized by a hydrothermal method using KCl, Bi(NO3)3and g-C3N4 as precursors, over which the photocatalytic reduction of CO2 under visible light irradiation was conducted. The catalytic activity and the stability during CO2 photoreduction was studied. Moreover, effects of molar ratio of Bi OCl to g-C3N4, usage amount of catalyst and illumination intensity on the photocatalytic reduction of CO2 was investigated. It suggests that the Bi OCl/g-C3N4 heterojunction catalysts showed much enhanced photocatalytic activities for the reduction of gaseous CO_2 with water vapor in comparison with Bi OCl and g-C3N4. The Bi OCl/g-C3N_4 catalyst with molar ratio of 1:1 exhibited the highest photocatalytic activity for CO2 reduction under the optimal conditions of 0.1 g catalyst and 2.413×10-6 einstein·min-1·cm-2 of illumination intensity. Moreover, the catalyst maintained stable performance even after five cycles of test. Techniques of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller analyses and UV-vis absorption spectroscopy were conducted on the catalyst, and it is speculated that the effective separation of photogenerated electrons and holes due to the formation of p-n heterojunctions between Bi OCl and g-C3N4 accounted for the improved photocatalytic activities of Bi OCl/g-C3N4.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2016年第11期4634-4642,共9页
CIESC Journal
基金
国家自然科学基金项目(21477117
21177115)
浙江省自然科学基金杰出青年项目(LR13B070002
LR14E080001)~~
关键词
催化剂
二氧化碳
还原
可见光
异质结
氯氧化铋
类石墨氮化碳
catalyst
carbon dioxide
reduction
visible light
heterojunction
bismuth oxychloride
graphitic carbon nitride