摘要
Cr(Ⅵ)污染物有毒有害且不可生物降解,会对环境造成严重破坏。光催化技术可实现Cr(Ⅵ)的有效去除,在解决环境污染问题方面具有良好前景。因此,本文通过在富含氧空位(OV)的BiOCl微球表面原位生长MIL-101(Fe)晶体,构建了一种新型富氧缺陷MOF基S型异质结催化剂-MIL1--101(Fe)/BiOCl。这种催化剂在高浓度Cr(Ⅵ)的光催化还原中表现出优异活性,60 min内对Cr(Ⅵ)溶液(10 mg·L^(-1),100 mL)的光还原效率达到88.5%,其光催化效率分别是BiOCl和MIL-101(Fe)的4.4和9.0倍。而且,MIL-101(Fe)/BiOCl还表现出良好的抗环境干扰性、稳定性和可重复使用性,显示出令人印象深刻的实际应用前景。实验结果表明,富含氧空位的S型MIL-101(Fe)/BiOCl异质结构暴露了大量活性位点,促进了界面电荷分离,提高了光生载流子的氧化还原能力,从而增强了光催化性能。另外,经过活性自由基检测发现,e^(-)和·O_(2)^(-)是光催化反应过程中的主要活性物种。这些研究结果将为开发用于环境治理的缺陷半导体/MOF S型光催化剂开辟新的途径。
Hexavalent chromium(Cr(Ⅵ))may be a hazardous and nonbiodegradable waste matter which will cause substantial environmental damage.Fabricating powerful photosystems to achieve efficacious elimination of Cr(Ⅵ)holds eminent promise in solving environmental issues.Thanks to their outstanding photo/electrical properties,large surface area,and customizable structure,metal-organic framework(MOF)catalysts have attracted widespread attention within the field of pollutant degradation and reduction.Nevertheless,due to the recombination of photo-generated charge carriers,pristine semiconductor MOFs'photocatalytic performance is inadequate.To overcome this challenge,one of the most typical and effective strategies is to create heterojunctions by combining MOFs with another semiconductor.Among these strategies,the innovative step-scheme(S-scheme)heterojunction has gained increasing prominence.Unlike traditional typeⅡand Z-scheme heterojunctions,the built-in electric field at the S-scheme heterojunction boundary enhances spatial charge separation and boosts redox capacity,thereby improving photocatalytic performance.In this study,a creative MOF-based S-scheme architecture with oxygen vacancies(OV)was built via in situ growth of MIL-101(Fe)crystals on the surface of OV-rich BiOCl microspheres.The optimized MIL-101(Fe)/BiOCl heterojunction exhibited exceptional photocatalytic performance in photo-reducing high concentrations of Cr(Ⅵ)and 88.5%of Cr(Ⅵ)solution(10 mg·L^(-1),100 m L)can be removed within 60 min,which is about 4.4 and 9.0 times that of BiOCl and MIL-101(Fe).Besides,the MIL-101(Fe)/Bi OCl manifests impressive practical implementation prospect due to its high antiinterference property,robustness and reusability.Photoelectron spectroscopy results validated that built-in electric field,bending band,and Coulomb attraction facilitated the transition of photoelectrons from the conduction band(CB)of BiOCl to the valence band(VB)of MIL-101(Fe),where they recombined with the photo-created holes.This suggests an S-scheme interfacial photo-carrier detachment mechanism at the MIL-101(Fe)/BiOCl interface.In addition,BET measurements indicated a notable increase in surface area with the introduction of MIL-101(Fe).The OV-rich S-scheme MIL-101(Fe)/BiOCl heterostructure boasts more reactive sites,enhanced interfacial charge separation,and optimal redox ability of photo-carriers,leading to enhanced photocatalytic properties.Measurements of active radical scavenging and electron spin resonance(ESR)confirm that e~-and·O_2~-are the primary active species during photocatalysis.These discoveries would open up new avenues for developing defective semiconductor/MOF S-scheme photocatalyst for environmental purification.
作者
王春春
游常俊
戎珂
申楚琦
杨方
李世杰
Chunchun Wang;Changjun You;Ke Rong;Chuqi Shen;Fang Yang;Shijie Li(Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province,National Engineering Research Center for Marine Aquaculture,College of Marine Science and Technology,Zhejiang Ocean University,Zhoushan 316022,Zhejiang Province,China;School of Mechanical and Automotive Engineering,Shanghai University of Engineering Science,Shanghai 201620,China.)
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2024年第7期50-53,共4页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(U1809214,51708504)
浙江省自然科学基金(LY20E080014)
舟山科技项目(2022C41011)资助项目。
