Shaodong Sun

Facile Water-Assisted Synthesis of Cupric Oxide Nanourchins and Their Application as Nonenzymatic Glucose Biosensor

We have demonstrated an interesting approach for the one-pot synthesis of cupric oxide (CuO) nanourchins with sub-100 nm through a sequential dissolution-precipitation process in a water/ethanol system. The first stage produces a precursory crystal [Cu7Cl4(OH)10H2O] that is transformed into monoclinic CuO nanourchins during the following stage. Water is a required reactant for the morphology-controlled growth of different CuO nanostructures. When evaluated for their nonenzymatic glucose-sensing properties, these CuO nanourchins manifest higher sensitivity. Significantly, this water-dependent precursor transformation method may be widely used to effectively control the growth of other metal oxide nanostructures.

The crystal-facet-dependent effect of polyhedral Cu2O microcrystals on photocatalytic activity

We have systematically investigated the crystal-facet-dependent effect of polyhedral Cu2O microcrystals exposed with different-index facets on photodegradation of methyl orange, which provides the convincing evidence that the performance of catalysts can be enhanced by high-index facets tailoring.

Highly symmetric polyhedral Cu2O crystals with controllable-index planes

Novel highly symmetric multi-faceted polyhedral Cu2O crystals enclosed by controllable high-index facets and different low-index facets have been synthesized via a template-free complex-precursor solution route. The formation and evolution of these polyhedral shapes can be attributed to the aggregation and ripening mechanism with face-selective adsorption. The appearance of these novel polyhedral architectures further enriches the current morphologies of Cu2O crystals, and might become useful for the fundamental study of crystals design.

Recent advances in tuning crystal facets of polyhedral cuprous oxide architectures

Polyhedral inorganic crystals exposed with controllable-index facets is as significant as size, composition, phase and crystallinity in determining their chemical and physical properties. To accurately tune the exposed facets and morphologies of crystals is imperative because a thorough understanding of the formation mechanism and unique performance has significant scientific value. Better understanding of the control of exposed facets would bring about new capability for us to design necessary structures for actual applications. This article presents recent research progress in the development of polyhedral Cu2O architectures, focusing on the expanding of crystal-facet-dependent properties. The challenge and prospects of polyhedral Cu2O architectures are discussed. The present article provides important scientific references and a basis for future work.

Templating synthesis of hollow CuO polyhedron and its application for nonenzymatic glucose detection

In this report, a novel type of a hollow CuO polyhedron-modified electrode for sensitive nonenzymatic glucose detection has been fabricated by a templating approach. The morphologies and structures were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). These results show that the as-prepared hollow CuO consists of numerous CuO nanoplates. The electrochemical performance for glucose detection was investigated by cyclic voltammetry and chronoamperometry. The hollow CuO polyhedron-modified electrode exhibits a high sensitivity of 1112 μA mM−1 cm−2 with a detection limit of 0.33 μM (S/N = 3) at +0.55 V, and the linear range is up to 4 mM. Moreover, the hollow CuO polyhedron-modified electrode is highly resistant to the interference from interfering species such as sodium chloride (NaCl), ascorbic acid (AA) and uric acid (UA). The hollow CuO polyhedron-modified electrode exhibits high sensitivity, low detection limit, good stability and fast response towards the oxidation of glucose; thus, it may be a promising nonenzymatic glucose sensor.

Surfactant-free CuO mesocrystals with controllable dimensions: green ordered-aggregation-driven synthesis, formation mechanism and their photochemical performances

We have demonstrated the significant evidence on a green synthesis for the ordered-aggregation-driven growth from surfactant-free one-dimensional (1D) CuO nanosubunits into dimension-controlled mesostructures (three-dimensional (3D) mesospindles and two-dimensional (2D) mesoplates) by an additive-free complex–precursor solution route. Structural and morphological evolutions were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and field-emission scanning electron microscopy (FESEM). The formation of CuO mesostructures here is essentially determined by the characteristic of [Cu(OH)4]2− precursors, and an oriented nanoparticle aggregation with tailoring shapes in different dimensions can be achieved in different concentration of reactants at higher reaction temperature. The 3D “layer-by-layer” growth of mesostructural CuO spindles is successfully synthesized in low concentrations of reagents, while the 2D “shoulder-by-shoulder” growth of mesostructural CuO plates is obtained in high concentrations of reagents. The study is of great importance in the bottom-up assembly of controllable ordering architectures, and offers a good opportunity to understand the fundamental significance for the investigation of the formation mechanism and growth process of surfactant-free CuO mesostructures with controllable aggregation-based behaviours. Additionally, we further demonstrated that such CuO mesocrystals could serve as a potential photocatalyst for the degradation of rhodamine B (RhB) under visible light irradiation in the presence of hydroxide water (H2O2). The results also suggest that these 3D mesostructural CuO spindles exhibit a higher adsorption and photocatalytic degradation of RhB than that of 2D mesostructural CuO plates.

Facet-selective growth of Cu–Cu2O heterogeneous architectures

We have demonstrated a facile protocol for the synthesis of facet-selective growth of low-cost metal Cu nanoparticles on {111} facets of polyhedral 26-facet Cu2O architectures. The novel Cu–Cu2O heterogeneous architectures show better adsorption and photodegradation of methyl orange than those of the original Cu2O architectures.

Nanoparticle-aggregated CuO nanoellipsoids for high-performance non-enzymatic glucose detection

We have demonstrated a facile anion-assisted strategy for the synthesis of nanoparticle-aggregated CuO nanoellipsoids. Structural and morphological evolutions were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). The nanoparticle-aggregated CuO nanoellipsoids serve as a promising electrode material for a non-enzymatic glucose biosensor which shows high sensitivity, good reproducibility, a fast amperometric response and good selectivity. The study is of great importance in the bottom-up assembly of tunable ordered architectures, and offers a chance to understand the formation mechanism and fundamental significance of an anion-assisted strategy for the synthesis of metal oxides. Significantly, it is believed that the anion-assisted synthetic approach reported here could provide a facile way to design more novel metal oxide architectures with well-defined shapes.

Bottom-up assembly of hierarchical Cu2O nanospheres: controllable synthesis, formation mechanism and enhanced photochemical activities

A facile additive-assisted complex-precursor solution method is demonstrated for one-pot assembly of well-defined hierarchical Cu2O nanospheres with tunable sizes and shapes. Structural and morphological evolutions were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and field-emission scanning electron microscopy (FESEM). The formation mechanism of these hierarchical nanostructures was rationally proposed, which can be attributed to the synergic effect of nanoparticle-aggregation and ripening with facet-selective adsorption. Significantly, it is believed that the additive-driven assembly of hierarchical architectures reported here would provide a facile way to design other exciting metal oxide nanostructures with controllable sizes. The photocatalytic superiority and stability for the methyl orange (MO) photodegradation by the hierarchical Cu2O nanospheres could be attributed to their exposed high active facets, which would be quite feasibly used for application in the fields of photocatalytic hazard pollutants.

Etching-limited branching growth of cuprous oxide during ethanol-assisted solution synthesis

An etching-limited branching growth mechanism has been elucidated during ethanol-assisted solution synthesis of octahedral Cu2O crystals, which is different from the conventional diffusion-limited aggregate and recent overpotential-limited branching mechanism. It provides an innovative approach for revealing the shape evolution from habit formation (octahedron) to branching growth (hexapod-like architecture) via adjusting the competition between preferential growth and selective oxidative etching, and displays a constructive model system for fundamental research of crystal growth and design.