物理化学学报2023，Vol.39Issue(10)：4-13,10.DOI:10.3866/PKU.WHXB202306037
TiO2负载超低含量AuPd纳米颗粒在水蒸气条件下实现稳定的光催化甲烷偶联生成乙烷
Stable Photocatalytic Coupling of Methane to Ethane with Water Vapor Using TiO2 Supported Ultralow Loading AuPd Nanoparticles
摘要
Abstract
The selective conversion of methane to C2 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 C2 compounds under flowing conditions using cost-effective photocatalysts remains great challenge.In this work,we synthesized an ultralow loading AuPd alloy nanoparticle-supported on TiO2(AAu0.05-Pd0.05/TiO2)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 CO-diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)confirmed its composition and structure.The performance of the Au0.05-Pd0.05/TiO2 photocatalyst in methane conversion was evaluated under flow-reaction conditions.Remarkably,the photocatalyst efficiently converted methane containing water vapor into C2 compounds,including ethane and ethylene,with a remarkable C2 production rate of up to 10092 μmol 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 CO2.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 Au0.05-Pd0.05/TiO2 originates from the synergistic effect of Au and Pd,which promotes the separation of photogenerated carriers and facilitates the C—C bond coupling of CH3 to produce C2 compounds.Furthermore,XPS characterization revealed that the introduction of water vapor replenished consumed lattice oxygen during the methane activation process,thus contributing to the catalyst's stability.This study not only offers a cost-effective and efficient photocatalyst for methane conversion but also provides insights into the fundamental mechanism of photocatalytic methane conversion.We believe that our work will inspire the exploration of inexpensive catalysts with simple preparation methods,driving advancements in efficient methane to C2 compound conversion and contributing to sustainable photocatalytic pathways for the future.关键词
光催化/甲烷/流动反应/水蒸气/AuPd合金纳米颗粒/C2化合物Key words
Photocatalysis/Methane/Flow-reaction/Water vapor/AuPd alloy nanoparticle/C2 compounds分类
化学引用本文复制引用
谢君,蒋雨恒,李思扬,徐鹏,郑强,范晓宇,彭海琳,唐智勇..TiO2负载超低含量AuPd纳米颗粒在水蒸气条件下实现稳定的光催化甲烷偶联生成乙烷[J].物理化学学报,2023,39(10):4-13,10.基金项目
The project was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB36000000),National Key Basic Research Program of China(2021YFA1200302),and National Natural Science Foundation of China(92056204,21890381,21721002).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)及国家自然科学基金(92056204,21890381,21721002)资助项目 （XDB36000000）
