Rui Liu,Chunlei Pei,Xianhua Zhang,Sai Chen,Hongfang Li,Liang Zeng,Rentao Mu,Jinlong Gong
This paper describes the design of a FeWO x -based oxygen carrier for the chemical partial oxidation of methane (CLPOM). Thermodynamic screening and kinetic analyses both forecast the FeWO x -based oxygen carrier as a promising candidate for the production of syngas. The total methane conversion and syngas yield can be dramatically increased with this catalyst compared to the case with the unmodified WO 3 /SiO 2 , thereby enabling CLPOM with 62% methane conversion, 93% CO gas-phase selectivity, 94% H 2 selectivity, and a 2.4 H 2 /CO ratio. The catalyst has the advantages of high availability of lattice oxygen to oxidize carbonaceous intermediates in time, together with the formation of an Fe-W alloy to promote the surface reaction. Consequently, it demonstrates excellent catalytic performance with no catalyst deactivation at 900 °C and 1 atm. The excellent structural stability plays an essential role in CLPOM. As revealed via XPS and ICP, the phase segregation has not been observed due to the strong interaction between Fe and W, which resulted in the formation of the Fe-W alloy during the reduction processes and the match between the ion oxidation rates of the Fe and W ions in the oxidation stage. The results provide fundamental information on the reaction mechanism of FeWO x /SiO 2 , and present it as a promising candidate for CLPOM.
Modulating the hostile tumor microenvironment (TME) rather than directly killing cancer cells may be an effective strategy to improve the therapeutic benefits in cancer treatment. Herein, FeWO X nanosheets are constructed as cascade bioreactors to modulate the TME and enhance radiotherapy and immunotherapy of tumors. Synthesized by the thermal-decomposition method and modified by poly(ethylene glycol) (PEG), the obtained FeWO X -PEG with multivalent metal elements (Fe 2+/3+ , W 5+/6+ ) exhibit efficient catalytic decomposition of hydrogen peroxide (H 2 O 2 ) to generate hydroxyl radicals (•OH) for chemo-dynamic therapy (CDT). The generated high valence of metal ions (Fe 3+ /W 6+ ) in FeWO X -PEG are reduced by endogenous glutathione (GSH), both leading to depletion of GSH and further amplified oxidative stress, and resulting in the reduced metal valence statuses (Fe 2+ /W 5+ ) enabling cascade bioreactions. Such FeWO X -PEG bioreactors enhance the oxidative stress in the tumor and interact with X-rays, significantly improving cancer radiotherapy (RT). Furthermore, the reactive oxygen species (ROS)-induced inflammation caused by FeWO X -PEG in TME activates the immune system and promotes the tumor-infiltration of various types of immune cells, which working together with cytotoxic T-lymphocyte antigen-4 (CTLA-4) checkpoint blockade could elicits a robust immune response to defeat tumors.
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