The low efficiency of photogenerated carrier separation,and the poor adsorption and activation ability of CO_(2)on the surface of photocatalyst were the key problems to limit the efficiency of photocatalytic CO_(2)red...The low efficiency of photogenerated carrier separation,and the poor adsorption and activation ability of CO_(2)on the surface of photocatalyst were the key problems to limit the efficiency of photocatalytic CO_(2)reduction.Hence,maximally accelerating the immigration of photogenerated charges d increasing the number of active sites are critical points to boost the overall performance of photocatalytic CO_(2)reduction.However,it is still huge challenge.In this work,the Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets,which was successfully prepared by hydrothermal and ultrasonic chemical stripping methods,exhibited efficient photocatalytic conversion of CO_(2)to CO.The results of experiments and theoretical calculations indicated that the doped Ni^(2+)significantly increased the crystal dipole moment of Bi_(4)O_(5)Br_(2)in y direction(from 0 to 0.096 e?),which enhanced the polarized electric field strength inside Bi_(4)O_(5)Br_(2),and further promoted the immigration of photogenerated carriers.Meanwhile,the ultrathin structure and doped Ni^(2+)synergistically increased the number of active sites,thereby promoting the adsorption and activation of CO_(2)molecules,as evidenced by experimental and theoretical results collectively.As result,The CO yield was as high as 26.57μmol g–1 h–1 for the prepared Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets under full spectrum light irradiation,which was 9.48 times that of Bi_(4)O_(5)Br_(2).Therefore,it is of great scientific significance in this study to explore strategies to promote the separation of photogenerated carriers and enhance the adsorption and activation ability of CO_(2)on the surface.展开更多
采用超声辅助室温原位沉淀法合成BC/Bi_(4)O_(5)Br_(2)光催化剂,在可见光下对比了TiO_(2)体系、BC/Bi_(4)O_(5)Br_(2)体系以及BC/Bi_(4)O_(5)Br_(2)耦合过一硫酸盐(PMS)体系处理渗滤液尾水的效果。考察了BC/Bi_(4)O_(5)Br_(2)耦合PMS体...采用超声辅助室温原位沉淀法合成BC/Bi_(4)O_(5)Br_(2)光催化剂,在可见光下对比了TiO_(2)体系、BC/Bi_(4)O_(5)Br_(2)体系以及BC/Bi_(4)O_(5)Br_(2)耦合过一硫酸盐(PMS)体系处理渗滤液尾水的效果。考察了BC/Bi_(4)O_(5)Br_(2)耦合PMS体系中PMS投加量和反应时间的影响,通过紫外可见光谱、三维荧光图谱分析渗滤液尾水有机物成分。结果表明:BC/Bi_(4)O_(5)Br_(2)耦合PMS体系对腐殖质的去除效果较另外两体系的效果优异,BC/Bi_(4)O_(5)Br_(2)对COD、腐殖质(A_(254))、色度(CN)的去除率分别为13.07%、12.74%、52.19%,BOD_(5)/COD从0.08提升至0.18。BC/Bi_(4)O_(5)Br_(2)耦合PMS体系中,0.1 g BC/Bi_(4)O_(5)Br_(2)耦合0.20 g PMS体系对渗滤液尾水有机物有良好的降解效果,尤其在反应开始的前0.5 h作用效果明显,1.5 h后降解效率不再明显增加。BC/Bi_(4)O_(5)Br_(2)耦合PMS体系对TOC的最大去除率为30.5%,较BC/Bi_(4)O_(5)Br_(2)体系提高16.5%;对腐殖质的最大去除率为53.97%,较BC/Bi_(4)O_(5)Br_(2)体系提升41.5%。紫外可见光谱、三维荧光图谱表明渗滤液尾水以类腐殖质为主。研究结果可为非均相耦合过一硫酸盐光催化处理渗滤液尾水提供一定参考。展开更多
文摘The low efficiency of photogenerated carrier separation,and the poor adsorption and activation ability of CO_(2)on the surface of photocatalyst were the key problems to limit the efficiency of photocatalytic CO_(2)reduction.Hence,maximally accelerating the immigration of photogenerated charges d increasing the number of active sites are critical points to boost the overall performance of photocatalytic CO_(2)reduction.However,it is still huge challenge.In this work,the Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets,which was successfully prepared by hydrothermal and ultrasonic chemical stripping methods,exhibited efficient photocatalytic conversion of CO_(2)to CO.The results of experiments and theoretical calculations indicated that the doped Ni^(2+)significantly increased the crystal dipole moment of Bi_(4)O_(5)Br_(2)in y direction(from 0 to 0.096 e?),which enhanced the polarized electric field strength inside Bi_(4)O_(5)Br_(2),and further promoted the immigration of photogenerated carriers.Meanwhile,the ultrathin structure and doped Ni^(2+)synergistically increased the number of active sites,thereby promoting the adsorption and activation of CO_(2)molecules,as evidenced by experimental and theoretical results collectively.As result,The CO yield was as high as 26.57μmol g–1 h–1 for the prepared Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets under full spectrum light irradiation,which was 9.48 times that of Bi_(4)O_(5)Br_(2).Therefore,it is of great scientific significance in this study to explore strategies to promote the separation of photogenerated carriers and enhance the adsorption and activation ability of CO_(2)on the surface.
文摘采用超声辅助室温原位沉淀法合成BC/Bi_(4)O_(5)Br_(2)光催化剂,在可见光下对比了TiO_(2)体系、BC/Bi_(4)O_(5)Br_(2)体系以及BC/Bi_(4)O_(5)Br_(2)耦合过一硫酸盐(PMS)体系处理渗滤液尾水的效果。考察了BC/Bi_(4)O_(5)Br_(2)耦合PMS体系中PMS投加量和反应时间的影响,通过紫外可见光谱、三维荧光图谱分析渗滤液尾水有机物成分。结果表明:BC/Bi_(4)O_(5)Br_(2)耦合PMS体系对腐殖质的去除效果较另外两体系的效果优异,BC/Bi_(4)O_(5)Br_(2)对COD、腐殖质(A_(254))、色度(CN)的去除率分别为13.07%、12.74%、52.19%,BOD_(5)/COD从0.08提升至0.18。BC/Bi_(4)O_(5)Br_(2)耦合PMS体系中,0.1 g BC/Bi_(4)O_(5)Br_(2)耦合0.20 g PMS体系对渗滤液尾水有机物有良好的降解效果,尤其在反应开始的前0.5 h作用效果明显,1.5 h后降解效率不再明显增加。BC/Bi_(4)O_(5)Br_(2)耦合PMS体系对TOC的最大去除率为30.5%,较BC/Bi_(4)O_(5)Br_(2)体系提高16.5%;对腐殖质的最大去除率为53.97%,较BC/Bi_(4)O_(5)Br_(2)体系提升41.5%。紫外可见光谱、三维荧光图谱表明渗滤液尾水以类腐殖质为主。研究结果可为非均相耦合过一硫酸盐光催化处理渗滤液尾水提供一定参考。
