摘要
选择性转化甲烷为C_(2)烃类是一种高效利用天然气并减少对传统化石燃料依赖的方法。与高温高压的热催化途径不同,光催化方法可以在温和条件下实现甲烷活化和选择性转化,是一种非常具有前景的可持续途径。然而,使用廉价光催化剂在流动条件下实现高效C_(2)化合物的生成仍然是一个巨大挑战。本文通过简单的化学还原法合成了一种具有超低负载量的AuPd合金纳米颗粒负载的TiO_(2)光催化剂(Au_(0.05)-Pd_(0.05)/TiO_(2)),用于光催化甲烷转化。在流动反应条件下,含水蒸气的甲烷可以高效转化为包括乙烷和乙烯在内的C_(2)化合物,C_(2)产率高达10092μmol·g^(−1)·h^(−1),选择性为77%。更重要的是,在反应持续32 h后,催化活性没有显著降低。Au_(0.05)-Pd_(0.05)/TiO_(2)的光催化甲烷转化的活性和稳定性超过了迄今为止报道的结果。Au_(0.05)-Pd_(0.05)/TiO_(2)良好的催化活性可以归因于金和钯的协同效应,不仅促进了光生载流子的分离而且有利于·CH_(3)的C―C键耦合进而产生C_(2)化合物。同时,引入水蒸气有助于及时补充在甲烷活化过程中消耗的晶格氧,从而保持催化剂的稳定性。这项工作有望为设计甲烷到C_(2)化合物的可持续光催化转化途径提供一个典范。
The selective conversion of methane to C_(2) hydrocarbons offers a sustainable approach to utilize natural gas efficiently and reduce reliance on conventional fossil fuels.Unlike the conventional thermal catalytic conversion that requires high temperatures and pressures,the photocatalytic pathway enables methane activation and selective conversion under mild conditions,holding great promise as a sustainable method.However,achieving the efficient generation of C_(2) compounds under flowing conditions using cost-effective photocatalysts remains great challenge.In this work,we synthesized an ultralow loading AuPd alloy nanoparticle-supported on TiO_(2)(Au_(0.05)-Pd_(0.05)/TiO_(2))photocatalyst via simple chemical reduction.Characterization using X-ray diffraction(XRD),aberration corrected high-angle annular dark field scanning transmission electron microscopy(AC-HAADF-STEM)and in situ COdiffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)confirmed its composition and structure.The performance of the Au_(0.05)-Pd_(0.05)/TiO_(2)photocatalyst in methane conversion was evaluated under flow-reaction conditions.Remarkably,the photocatalyst efficiently converted methane containing water vapor into C_(2) compounds,including ethane and ethylene,with a remarkable C_(2) production rate of up to 10092μmol·g^(−1)·h^(−1) and a selectivity of 77%.While water vapor was not essential for methane conversion,its presence enhanced the production of ethane and ethylene while suppressing overoxidation to CO_(2).The photocatalyst demonstrated excellent stability,maintaining its catalytic activity even after continuous reaction for 32 h,surpassing previously reported results.With the assistant of transient photocurrent response test,in situ X-ray photoelectron spectroscopy spectra and in situ DRIFTS,we uncovered that the exceptional catalytic activity of Au_(0.05)-Pd_(0.05)/TiO_(2)originates from the synergistic effect of Au and Pd,which promotes the separation of photogenerated carriers and facilitates the C―C bond
作者
谢君
蒋雨恒
李思扬
徐鹏
郑强
范晓宇
彭海琳
唐智勇
Jun Xie;Yuheng Jiang;Siyang Li;Peng Xu;Qiang Zheng;Xiaoyu Fan;Hailin Peng;Zhiyong Tang(Chinese Academy of Science(CAS)Key Laboratory of Nanosystem and Hierarchy Fabrication,CAS Center for Excellence in Nanoscience,National Center for Nanoscience and Technology,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Academy for Advanced Interdisciplinary Studies,Peking University,Beijing 100871,China;CAS Key Laboratory of Standardization and Measurement for Nanotechnology,National Center for Nanoscience and Technology,Beijing 100190,China;Center for Nanochemistry,Beijing Science and Engineering Center for Nanocarbons,Beijing National Laboratory for Molecular Sciences,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China.)
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2023年第10期1-10,共10页
Acta Physico-Chimica Sinica
基金
中国科学院战略性先导科技专项(XDB36000000)
国家重点基础研究计划(2021YFA1200302)
国家自然科学基金(92056204,21890381,21721002)资助项目。
