Fe/CeO2 中 Fe 取代掺杂和表面紧密接触 Fe2O3/CeO2 异质结的协同效应增强 CH4 光催化转化,Journal of Materials Chemistry A

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Fe/CeO2 中 Fe 取代掺杂和表面紧密接触 Fe2O3/CeO2 异质结的协同效应增强 CH4 光催化转化
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2023-05-15 , DOI: 10.1039/d3ta00720k
Hailong Tang ₁ , Meiling Wang ₁ , Yongqing Ma _{1,

2} , Xiao Sun ₃ , Min Wang ₄ , Ganhong Zheng ₁

Affiliation

第一个 C-H 键的断裂是实现 CH ₄转化的一个巨大挑战。在此，我们设计了 Fe/CeO ₂复合催化剂，旨在降低 C-H 键的活化能并提高 CH ₄转化率。X 射线衍射光谱和高分辨率透射电子显微镜图像均证实了 Fe/CeO ₂固溶体相和表面紧密接触的 Fe ₂ O ₃ /CeO ₂异质结构的共存。_{密度泛函理论计算验证了置换掺杂 Fe 位点上明显的电荷积累，有效降低了 CH 4}裂解形成 *CH ₃的反应能通过诱导 CH ₄不对称极化。此外，利用能带结构和原位X射线光电子能谱综合研究了有效存在的表面紧密接触的Fe ₂ O ₃ /CeO _{2异质结，提高了载流子分离效率，进一步提高了光催化性能。}原位傅里叶变换红外光谱表明CH ₄在催化剂表面的吸附和快速离解是稳定的。对于优化后的样品，C1 产物的产率为 10.56 mmol g _cat。^-1 h ^{-1是在 H}₂ O存在的情况下实现的₂，优于我们所知的几乎所有以前的报告。_{该工作阐述了Fe/CeO 2}中不同Fe位点在_{CH 4}光催化转化过程中，对未来复合催化剂的发展方向具有指导意义。

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Synergistic effects of Fe-substitutional-doping and a surface close-contact Fe2O3/CeO2 heterojunction in Fe/CeO2 for enhanced CH4 photocatalytic conversion

The cleavage of the first C–H bond is a great challenge in achieving CH₄ conversion. Herein, we designed Fe/CeO₂ composite catalysts with efforts to reduce the activation energy of the C–H bond and improve CH₄ conversion. Both X-ray diffraction spectra and high-resolution transmission electron microscopy images confirmed the coexistence of an Fe/CeO₂ solid-solution phase and the surface close-contact Fe₂O₃/CeO₂ heterostructure. Density functional theory calculations validate distinct charge accumulations on the substitutional-doped Fe sites, which effectively lowered the reaction energy of CH₄ cleavage to form *CH₃ through induced CH₄ asymmetric polarization. Moreover, the existed surface close-contact Fe₂O₃/CeO₂ heterojunction effectively, which was comprehensively studied by using the band structure and in situ X-ray photoelectron spectra, improved carrier separation efficiency and further improved photocatalytic performance. In situ Fourier transform infrared spectra indicated the steady stream of CH₄ adsorption and quick dissociation on the catalyst surface. For the optimized sample, a high C1 product yield of 10.56 mmol g_cat.⁻¹ h⁻¹ was achieved with the presence of H₂O₂, outperforming almost all previous reports as we know. This work elaborates the different roles of varied Fe sites in Fe/CeO₂ during the photocatalytic conversion of CH₄, which has guiding significance for the development direction of composite catalysts in the future.

更新日期：2023-05-15

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