纳米负载型选择性催化还原反应催化剂的制备和性能研究

采用溶胶凝胶法和浸渍法制备了以陶瓷颗粒为骨架的纳米级V2O5-WO3/TiO2(C)催化剂,并用X射线衍射(X-ray diffraction,XRD)和扫描电子透镜(transmission electron microscopy,TEM)表征了催化剂的晶型和形貌。研究了TiO2凝胶热处理温度和WO3负载量等重要参数对催化剂在以NH3为还原剂的选择性催化还原(selective catalytic reduc- tion,SCR)系统中的反应温度窗口、抗硫性的影响。最后考察了催化剂在不同NH3/NO比、O2含量、空速等因素下的性能指标。结果表明,在260~420℃的温度范围内,以陶瓷为骨架的负载型纳米V2O5-WO3/TiO2催化剂具有较高的SCR催化活性,且性能稳定; TiO2以锐钛形式存在的催化剂表现出高的抗硫性能,而TiO2以锐钛和金红石混晶形式存在时,抗硫性能比较差,但硫的中毒是可逆的,可再生;WO3负载量的增加提高了催化剂的活性。     

纳米催化剂对双基系推进剂燃烧性能的影响

研究了10种不同纳米催化剂对双基或RDX—CMDB推进剂燃烧性能的影响,发现经表面处理的纳米复合物(n—TPCC)是一种非常有效的纳米催化剂,它使得双基推进剂在6～10MPa呈现麦撤燃烧特征,8～IOMPa的压力指数为-0．867;改进n—TPCC加入方法后,可显著提高n—TPCC在低压下的催化效率;在RDX—CMDB推进剂中,n—TPCC与碳黑复合后,其催化效率进一步提高,且使推进剂在12-22MPa出现了一个宽压力范围的平台区,燃速压力指数小于0．3。     

低温油相合成金钯纳米粒子及其催化性能研究

采用低温油相法合成了不同金钯量比的双金属纳米催化剂,对其形貌和电催化性能进行了分析。透射电镜表征结果显示,金钯的量比对催化剂的分散性和纳米颗粒的尺寸有一定的影响。当金钯等量比时,分散性最好、纳米颗粒的粒径最小。而电化学测试表明,当金钯等量比时,高分散、小尺寸的金钯纳米催化剂更易于裸露有效活性位点,从而对甲酸和乙醇显示出较高的催化活性和稳定性。     

等离子体制备负载型金属纳米催化剂的研究进展

等离子体主要是由离子、电子等粒子组成的呈电中性且高度离子化的气体。可在室温条件下,利用等离子体中的高能粒子对化学物质进行还原,避免高温条件下粒子发生团聚,易得到粒径小、分散性好的纳米颗粒。对近年来等离子体技术制备负载型金属纳米催化剂及其催化性能进行了综述。     

Boosting Chemoselective Hydrogenation of Nitroaromatic via Synergy of Hydrogen Spillover and Preferential Adsorption on Magnetically Recoverable Pt@Fe2O3

It is highly desired but challenging to design high performance catalyst for selective hydrogenation of nitro compounds into amino compounds. Herein, a boosting chemoselective hydrogenation strategy on Pt@Fe₂O₃ is proposed with gradient oxygen vacancy by synergy of hydrogen spillover and preferential adsorption. Experimental and theoretical investigations reveal that the nitro is preferentially adsorbed onto oxygen vacancy of Pt@Fe₂O₃, meanwhile, the H₂ dissociated on Pt nanoparticles and then spillover to approach the nitro for selective hydrogenation (>99% conversion of 4-nitrostyrene, > 99% selectivity of 4-aminostyrene, TOF of 2351 h⁻¹). Moreover, the iron oxide support endows the catalyst magnetic retrievability. This high activity, selectivity, and easy recovery strategy provide a promising avenue for selective hydrogenation catalysis of various nitroaromatic.     

Enhanced Chemodynamic Therapy Mediated by a Tumor-Specific Catalyst in Synergy with Mitophagy Inhibition Improves the Efficacy for Endometrial Cancer

Chemodynamic therapy (CDT) relies on the tumor microenvironment (e.g., high H₂O₂ level) responsive Fenton-like reactions to produce hydroxyl radicals (·OH) against tumors. However, endogenous H₂O₂ is insufficient for effective chemodynamic responses. An NAD(P)H: quinone oxidoreductase 1 (NQO1)^high catalase (CAT)^low therapeutic window for the use of NQO1 bioactive drug β-lapachone (β-Lap) is first identified in endometrial cancer (EC). Accompanied by NADH depletion, NQO1 catalyzes β-Lap to produce excess H₂O₂ and initiate oxidative stress, which selectively suppress NQO1^high EC cell proliferation, induce DNA double-strand breaks, and promote apoptosis. Moreover, shRNA-mediated NQO1 knockdown or dicoumarol rescues NQO1^high EC cells from β-Lap-induced cytotoxicity. Arginine-glycine-aspartic acid (RGD)-functionalized iron-based metal-organic frameworks (MOF(Fe)) further promote the conversion of the accumulated H₂O₂ into highly oxidative ·OH, which in turn, exacerbates the oxidative damage to RGD-positive target cells. Furthermore, mitophagy inhibition by Mdivi-1 blocks a powerful antioxidant defense approach, ultimately ensuring the anti-tumor efficacy of stepwise-amplified reactive oxygen species signals. The tumor growth inhibition rate (TGI) is about 85.92%. However, the TGI of MOF(Fe)-based synergistic antitumor therapy decreases to only 50.46% in NQO1-deficient KLE tumors. Tumor-specific chemotherapy and CDT-triggered therapeutic modality present unprecedented therapeutic benefits in treating NQO1^high EC.