Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid and Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, China.
School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China.
Nat Commun. 2023 Feb 25;14(1):1092. doi: 10.1038/s41467-023-36721-8.
Amorphous nano-metal catalysts often exhibit appealing catalytic properties, because the intrinsic linear scaling relationship can be broken. However, accurate control synthesis of amorphous nano-metal catalysts with desired size and morphology is a challenge. In this work, we discover that Cu(0) could be oxidized to amorphous CuO species by supercritical CO. The formation process of the amorphous CuO is elucidated with the aid of machine learning. Based on this finding, a method to prepare Cu nanoparticles with an amorphous shell is proposed by supercritical CO treatment followed by electroreduction. The unique feature of this method is that the size of the particles with amorphous shell can be easily controlled because their size depends on that of the original crystal Cu nanoparticles. Moreover, the thickness of the amorphous shell can be easily controlled by CO pressure and/or treatment time. The obtained amorphous Cu shell exhibits high selectivity for C2+ products with the Faradaic efficiency of 84% and current density of 320 mA cm. Especially, the FE of C2+ oxygenates can reach up to 65.3 %, which is different obviously from the crystalline Cu catalysts.
无定形纳米金属催化剂通常表现出诱人的催化性能，因为可以打破内在的线性标度关系。然而，准确控制具有所需尺寸和形态的无定形纳米金属催化剂的合成仍然是一个挑战。在这项工作中，我们发现超临界 CO 可以将 Cu(0)氧化为无定形的 CuO 物种。借助机器学习阐明了无定形 CuO 的形成过程。基于这一发现，提出了一种通过超临界 CO 处理后再进行电还原来制备具有非晶壳的 Cu 纳米颗粒的方法。该方法的独特之处在于，由于无定形壳的颗粒尺寸取决于原始晶态 Cu 纳米颗粒的尺寸，因此可以很容易地控制具有非晶壳的颗粒的尺寸。此外，通过 CO 压力和/或处理时间可以很容易地控制非晶壳的厚度。所得的非晶 Cu 壳对 C2+产物表现出高选择性，法拉第效率为 84%，电流密度为 320 mA·cm。特别是，C2+含氧化合物的 FE 可高达 65.3%，这与晶态 Cu 催化剂明显不同。
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