Afreen Sadia, Zhu Jun Jie
State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, PR China.
State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, PR China.
Ultrason Sonochem. 2020 Oct;67:105178. doi: 10.1016/j.ultsonch.2020.105178. Epub 2020 May 18.
In this study, we proposed 'switching ultrasonic amplitude' as a new strategy of applying ultrasonic energy to prepare a hybrid of buckminsterfullerene (C) and gallium oxide (GaO), C/GaO. In the proposed method, we switched the ultrasonic amplitude from 25% to 50% (by 5% amplitude per 10 min, within 1 h of ultrasonic irradiation) for the sonochemical treatment of a heterogeneous aqueous mixture of C and GaO by a probe-type ultrasonic horn operating at 20 kHz. We found that compared to the conventional techniques associated with high amplitude oriented ultrasonic preparation of functional materials, switching ultrasonic amplitude can better perform in preparing C/GaO with respect to avoiding titanium (Ti) as an impurity generating from the tip erosion of a probe-type ultrasonic horn during high amplitude ultrasonic irradiation in an aqueous medium. Based on SEM/EDX analysis, the quantity of Ti (wt.%) in C/GaO prepared by the proposed technique of switching ultrasonic amplitude was found to be 1.7% less than that prepared at 50% amplitude of ultrasonic irradiation. The particles of C/GaO prepared by different modes of amplitude formed large (2-12 μm) aggregates in their solid phase.Whereas, in the aqueous medium, they were found to disperse in their nano sizes. The minimum particle size of the as-synthesized C/GaO in an aqueous medium prepared by the proposed method of switching ultrasonic amplitude reached to approximately 467 nm. Comparatively, the minimum particle sizes were approximately 658 nm and 144 nm, using 25% and 50% amplitude, respectively. Additionally, GaO went under hydration during ultrasonic irradiation. Moreover, due to the electron cloud interference from C in the hybrid structure of C/GaO, the vibrational modes of GaO were Raman inactive in C/GaO.
在本研究中，我们提出了“切换超声振幅”这一应用超声能量的新策略，用于制备富勒烯（C）与氧化镓（Ga₂O₃）的混合物C/Ga₂O₃。在所提出的方法中，我们通过一个工作频率为20kHz的探头式超声换能器，对C和Ga₂O₃的非均相水性混合物进行声化学处理，在超声辐照的1小时内，将超声振幅从25%切换到50%（每10分钟振幅增加5%）。我们发现，与用于功能材料高振幅定向超声制备的传统技术相比，切换超声振幅在制备C/Ga₂O₃时，能更好地避免在水介质中高振幅超声辐照期间因探头式超声换能器尖端腐蚀而产生钛（Ti）杂质。基于扫描电子显微镜/能谱分析（SEM/EDX），发现采用所提出的切换超声振幅技术制备的C/Ga₂O₃中Ti的含量（重量百分比）比在超声辐照振幅为50%时制备的少1.7%。通过不同振幅模式制备的C/Ga₂O₃颗粒在其固相中形成了大的（2 - 12μm）聚集体。然而，在水介质中，发现它们以纳米尺寸分散。通过所提出的切换超声振幅方法在水介质中合成的C/Ga₂O₃的最小粒径达到约467nm。相比之下，分别使用25%和50%振幅时，最小粒径约为658nm和144nm。此外，Ga₂O₃在超声辐照期间发生了水合作用。而且，由于在C/Ga₂O₃的混合结构中C的电子云干扰，Ga₂O₃的振动模式在C/Ga₂O₃中对拉曼散射不活跃。
