Herein, the desorption effect of supercritical CO2 (scCO2) was utilized to obtain sub-5 nm Ag NPs with the high Ag loading in the SBA-15. The Ag nanoparticles (NPs) size was decreased from 3.54 ± 0.79 nm (Ag loading 25.3 wt.% wt.%) to 2.38 ± 0.68 (Ag loading 10.5 wt.%) nm by changing depressurization curve from 0.1 MPa/min (20-14 MPa) to 3 MPa/min (20-12 MPa). Meanwhile, the intensity of crystalline Ag characteristic peaks was obviously higher than the latter sample from the x-ray diffraction (XRD) patterns. However, compared with the adsorption kinetics of two precursors of AgNO3 and Cu(NO3)2 on SBA-15, under the same deposition and depressurization conditions, when the two depositional systems used water as co-solvent, and the time reaching adsorption equilibrium of Ag+ on supports was longer than the time of Cu2+, which existed in the water as [Cu(H2O)4]2+. The surface of SBA-15 was hydrophilic, and then the interaction of Ag+ and the surface was weaker compared with Cu2+, making Ag+ highly dispersed on the surface under scCO2 desorption effect. After calcination, Ag NPs size was decreased, but the morphology of CuO was mainly characterized by nanorods (NRs). Moreover, by compared experiments of wetness impregnation, the dispersion ability of bulk scCO2 of the reactor was inefficient for Ag+ adsorbed on the channels in the depressurization process.

中文翻译：

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通过 SBA-15 中超临界 CO2 的解吸效应有效合成亚 5 nm 银纳米粒子

在此，利用超临界 CO2 (scCO2) 的解吸效应在 SBA-15 中获得具有高 Ag 负载量的亚 5 nm Ag NP。通过将减压曲线从 0.1 MPa/min (20- 14 兆帕）至 3 兆帕/分钟（20-12 兆帕）。同时，从 X 射线衍射 (XRD) 图中，结晶 Ag 特征峰的强度明显高于后一个样品。然而，与 AgNO3 和 Cu(NO3)2 两种前驱体在 SBA-15 上的吸附动力学相比，在相同的沉积和降压条件下，当两种沉积体系以水为助溶剂时，达到吸附平衡的时间为载体上的 Ag+ 比 Cu2+ 的时间长，以[Cu(H2O)4]2+的形式存在于水中。SBA-15的表面是亲水性的，然后Ag+与表面的相互作用比Cu2+弱，使得Ag+在scCO2解吸作用下高度分散在表面。煅烧后，Ag NPs 尺寸减小，但 CuO 的形态主要以纳米棒（NRs）为特征。此外，通过湿浸渍的对比实验，反应器本体scCO2的分散能力对于减压过程中吸附在通道上的Ag+是低效的。但是CuO的形态主要以纳米棒（NRs）为特征。此外，通过湿浸渍的对比实验，反应器本体scCO2的分散能力对于减压过程中吸附在通道上的Ag+是低效的。但是CuO的形态主要以纳米棒（NRs）为特征。此外，通过湿浸渍的对比实验，反应器本体scCO2的分散能力对于减压过程中吸附在通道上的Ag+是低效的。