One‐Pot Synthesis and Hierarchical Assembly of Hollow Cu₂O Microspheres with Nanocrystals‐Composed Porous Multishell and Their Gas‐Sensing Properties

Abstract

Hierarchical assembly of hollow microstructures is of great scientific and practical value and remains a great challenge. This paper presents a facile and one‐pot synthesis of Cu2O microspheres with multilayered and porous shells, which were organized by nanocrystals. The time‐dependent experiments revealed a two‐step organization process, in which hollow microspheres of Cu2(OH)3NO3 were formed first due to the Ostwald ripening and then reduced by glutamic acid, the resultant Cu2O nanocrystals were deposited on the hollow intermediate microspheres and organized into finally multishell structures. The special microstructures actually recorded the evolution process of materials morphologies and microstructures in space and time scales, implying an intermediate‐templating route, which is important for understanding and fabricating complex architectures. The Cu2O microspheres obtained were used to fabricate a gas sensor, which showed much higher sensitivity than solid Cu2O microspheres.

Green Synthesis of Copper Nano-Particles Using Asparagus adscendens Roxb. Root and Leaf Extract and Their Antimicrobial Activities

“…Metal compounds usually reduce into their respective nanoparticles because of proteins, enzymes and the phytochemicals with antioxidant or reducing properties present in plant extracts. Copper nanostructures have been demonstrated to possess properties useful for applications in gas sensing (Zhang et al, 2007), CO oxidation (White et al, 2006), Photo catalysis (Kuo et al, 2007), (Ho and Huang 2009), (Kuo and Huang 2008;Xu et al, 2006;Yu et al, 2007), photochemical evolution of H 2 from water (Yang et al, 2008), photocurrent generation and organic synthesis (Altman et al, 2007;McShane and Choi 2009). …”

“…Usually microemulsion (colloidal) techniques (Panigrahi et al, 2006), sonochemical reduction (Song et al, 2004), electrochemical (Zhong et al, 2008), microwave-assisted (Kapoor and Mukherjee 2003), and hydrothermal (Huang et al, 1997) syntheses are the main techniques for the synthesis of nanoparticles through the chemical approach. Physical methods for nanoparticles synthesis are laser (pulse) ablation (Zhang et al, 2007), vacuum vapor deposition (Lisiecki and Pileni 1993), pulsed wire discharge (PWD) (Tanori and Pileni 1997) and mechanical milling (Wu and Chen 2004).…”

Template free synthesis of CuS nanosheet-based hierarchical microspheres: an efficient natural light driven photocatalyst

“…2-5 Particularly, hierarchically structured spheres stimulate extensive research interest owing to their unusual structural features and extraordinary optical/electrical behaviour which can bring wide potential applications in numerous fields such as catalysts, drug-delivery carriers, sensors, biomedical diagnosis agents, rechargeable batteries and chemical reactors, etc. [6][7][8][9] Tremendous interest in the synthesis of nano-or microstructures and hierarchically structured spheres has been aroused. The conventional approaches to preparation of hollow structures with different shapes have involved the use of various removable or sacrificial templates, including hard ones (e.g., metal nanoparticles, silica spheres, and carbon spheres) 10,11 and soft ones (e.g., liquid drops, micelles, emulsion droplets, and even bacteria).…”

Chemosensitive properties of electrically conductive Cu(I) compounds at room temperature

“…The interactions between copper ions and NH 3 between the gas phase and the Cu + ion-conductor with modified concentrations of mobile copper atoms and copper vacancies. Recently some other copper(I)-ion-conductors were suggested for gas sensing, in particular cuprous oxide for the detection of nitrogen dioxide [6], ethanol [7] and hydrogen sulfide [8] and cuprous chloride for carbon monoxide [9]. The aim of the present work is to investigate the sensing properties of different ionic and mixed conducting copper(I) compounds for gases and vapors, in particular for ammonia.…”