The design of oxygen carriers is essential for the chemical looping partial oxidation of methane (CL-POM) in syngas production. LaFeO3 is a promising oxygen storage material, but the impact of its morphology on the reaction characteristics and mechanisms in CL-POM remains unclear. Herein, we synthesized and characterized LaFeO3 samples with diverse morphologies (cube, porous microsphere, irregular nanoparticle, and polyhedron) to explore how morphology governs crystal plane exposure, oxygen vacancy formation, and oxygen migration. Results showed that cubic LaFeO3 not only achieved outstanding oxygen storage capacity (4.18 mmol/g), 2.5 times that of the other three samples combined (1.64 mmol/g), but also demonstrated superior methane reactivity with good low-temperature activity (initial reaction temperature of 500 °C) and the highest methane conversion (78.26% at 750 °C). This impressive performance is due to the synergy between oxygen vacancies and the (110) crystal plane, which optimizes oxygen release and enhances methane adsorption and dissociation. DFT calculations further confirmed that the (110) plane has lower energy barriers for reaction processes than the (100) plane, and more oxygen vacancies enhance reactivity and oxygen migration. This work underscores the pivotal role of LaFeO3 morphology in advancing the design of oxygen storage materials and a redox catalyst.
The synthesis of multielement composite oxide nanomaterials containing Ce, Zr, Y, and Yb was investigated using a micro confined jet mixer reactor operated in continuous mode under supercritical water conditions. The obtained nanoparticles were characterized using ICP-AES, SEM-EDS, FTIR, Raman spectroscopy, XRD, and TEM. All samples exhibited a uniform particle shape and a narrow particle size distribution. An analysis of the d-spacing results using selected electron area diffraction (SAED) patterns confirmed the production of cubic-phase crystals. A BET test was employed to determine the specific surface area of the prepared nanoparticles. OSC and TPR techniques were utilized to characterize the oxygen storage capacity and reduction performance of the obtained samples, with an analysis conducted to determine how the different proportions of elements affected the performance of multielement mixed oxides. The ionic conductivity of multielement composite oxide was measured using alternating current impedance spectroscopy (EIS), and the impact of Y, Ce, and Yb on the electrolyte material’s ionic conductivity was analyzed.Keywords:confined jet mixer;multielement composite oxide;continuous hydrothermal flow synthesis;oxygen storage capacity;ionic conductivity
Zhongxi Xie,Shuang Liang,Xuechao Cai,Binbin Ding,Shanshan Huang,Zhiyao Hou,Ping’an Ma,Ziyong Cheng,Jun Lin
Hypoxia and overexpression of glutathione (GSH) are typical characteristics of the tumor microenvironment, which severely hinders cancer treatments. Here, we design a novel biodegradable therapeutic system, O2–Cu/ZIF-8@Ce6/ZIF-8@F127 (OCZCF), to simultaneously achieve GSH depletion and O2-enhanced combination therapy. Notably, the doped Cu2+ doubles the O2 storage capacity of the ZIF-8 matrix, which makes OCZCF an excellent pH-sensitive O2 reservoir for conquering tumor hypoxia, enhancing the photodynamic therapy (PDT) efficiency of chlorin e6 (Ce6) under 650 nm laser irradiation. Moreover, the released Cu2+ can act as a smart reactive oxygen species protector by consuming intracellular GSH. The byproduct Cu+ will undergo highly efficient Fenton-like reaction to achieve chemodynamic therapy (CDT) in the presence of abundant H2O2. The accompanying O2 will further alleviate hypoxia. The in vitro and in vivo experimental data indicate that OCZCF could cause remarkable tumor inhibition through enhanced synergetic PDT and CDT, which may open up a new path for cancer therapy.
危险品化学品经营许可证（带存储）