We synthesized a series of Ru-Ti-Ni/CNT electrodes to degrade levofloxacin in wastewater. The unique structure of Ni single-atom-kernelled Ru nanoparticles regulates the reaction process, producing a notable synergistic effect. The reaction kinetics constant of Ru-Ti-Ni/CNT with a Ru: Ti ratio of 10:0 outperforms Ni/CNT by 3.7 times and CNT alone by 16.4 times. Comprehensive characterizations revealed its morphology and structure nature. Ru nanoparticles can shield Ni, while Ni single-atom facilitates electron transfer in Ru nanoparticles, generating abundant reactive oxygen radicals (ROS) that degrade pollutants.
Xin Song,Fangjun Shao,Zijiang Zhao,Xiaonian Li,Zhongzhe Wei,Jianguo Wang
It is challenging to develop an alkyne semi-hydrogenation catalyst with both high selectivity and high activity, especially at low temperatures and low pressures. Herein, a single-atom Ni-modified Al2O3-supported Pd is proposed as a modulation strategy to optimize the selectivity of alkyne semi-hydrogenation. Sphere-difference-corrected transmission electron microscopy and synchrotron radiation confirm that Ni single atoms enter the alumina lattice in a highly dispersed state, while Pd is loaded on the Ni-modified support in the form of nanoparticles. For the semi-hydrogenation of phenylacetylene, the Pd0.5/Ni0.5@γ-Al2O3 catalyst with Pd and Ni loadings of 0.45 and 0.43 wt %, respectively, achieves 98% conversion and 94% selectivity at 298 K and 0.1 MPa. It also possesses good stability, as the activity remains unchanged after 10 cycles of application. The Pd0.5/Ni0.5@γ-Al2O3 catalyst inherits the high activity of Pd and the high selectivity of Ni to achieve efficient semi-hydrogenation of phenylacetylene at low temperatures and pressures, benefiting from the synergistic effect of Pd and Ni.
Xinjie Wang,Juntian Li,Juan Li,Binghua Jing,Yun Sun,Teng Wang,Didi Li,Haibo Huang,Zhimin Ao
Ligands play an important role in the dispersion of metal and catalytic activity in single-atom transition metal-doped catalysts (SATMCs). In this work, a series of oxygen-ligand (O-ligand)-single-atom-Ni/2-dimensional reduced graphene oxide (RGO) materials (SANiX-O-2DRGO (X = 0.5–5)) were fabricated by a simple one-step co-reduction method. The single Ni atom on SANi5-O-2DRGO is embedded into the RGO and ligated by four O-ligand atoms. A systematic study confirms that the O-ligand is conducive to the dispersion of Ni and the formation of SATMCs with high metal loading. Density functional theory (DFT) calculation results demonstrate that the d-band center value of O-ligand-single-atom-Ni is closer to the Fermi level than that of the conventional N coordination, which is beneficial for electronic transition and enhances catalytic activity, i.e., the O-ligand accelerates the electron transfer between the carrier and the single metal atom, thus improving the catalytic oxidation capacity of volatile organic compounds (VOCs) on SANi5-O-2DRGO. As a demonstration, SANi5-O-2DRGO exhibits excellent reusability, water resistance, and stability for ethyl acetate oxidation. The degradation of ethyl acetate remained at 100% over 150 hours of continuous onstream operation. The catalytic oxidation mechanism of ethyl acetate on SANi5-O-2DRGO was also investigated. The O-ligand atoms provide the key electron transfer in the activation of adsorbed oxygen and catalytic oxidation process of reaction intermediates.
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