Fabrication of cubic nanocages and nanoframes by dealloying Au/Ag alloy nanoboxes with an aqueous etchant based on Fe(NO3)(3) or NH4OH

Department of Chemistry, University of Washington Seattle, Seattle, Washington, United States
Nano Letters (Impact Factor: 12.94). 07/2007; 7(6):1764-9. DOI: 10.1021/nl070838l
Source: PubMed

ABSTRACT This paper describes a two-step procedure for generating cubic nanocages and nanoframes. In the first step, Au/Ag alloy nanoboxes were synthesized through the galvanic replacement reaction between Ag nanocubes and an aqueous HAuCl4 solution. The second step involved the selective removal (or dealloying) of Ag from the alloy nanoboxes with an aqueous etchant based on Fe(NO3)3 or NH4OH. The use of a wet etchant other than HAuCl4 for the dealloying process allows one to better control the wall thickness and porosity of resultant nanocages because there is no concurrent deposition of Au. By increasing the amount of Fe(NO3)3 or NH4OH added to the dealloying process, nanoboxes derived from 50-nm Ag nanocubes could be converted into nanocages and then cubic nanoframes with surface plasmon resonance (SPR) peaks continuously shifted from the visible region to 1200 nm. It is also possible to obtain nanocages with relatively narrow SPR peaks (with a full width at half-maximum as small as 180 nm) by controlling the amount of HAuCl4 used for the galvanic replacement reaction and thus the optimization of the percentage of Au in the alloy nanoboxes.

Download full-text


Available from: Xianmao Lu, Jan 11, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cubic ZnSnO3 nanocages, a geometrical cube-shape with a hierarchical structure composed of small nanoparticles as secondary units, are successfully synthesized via a facile hydrothermal process. These ZnSnO3 nanocages have hollow interiors and good-permeation surfaces, and are used for detecting different gases such as ethanol (C2H5OH), formaldehyde (HCHO), and hydrogen sulfide (H2S). These ZnSnO3 nanocages show good response, selectivity, response and recovery characteristics to H2S. It is found that ZnSnO3 nanocages have a response of 17.6–50ppm H2S at the optimal operating temperature of 310°C and the response time is shorter than 20s.
    Sensors and Actuators B Chemical 11/2011; 159(1):245-250. DOI:10.1016/j.snb.2011.06.080 · 3.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report the synthesis of flowerlike ZnO nanostructure using a facile hydrothermal process, and the investigation on the ammonia (NH3)-sensing properties of the pure and palladium (Pd)-sensitized flowerlike ZnO nanostructure. The phase purity, morphology, and structure of the pure and Pd-sensitized ZnO nanostructure are investigated. The characterized results reveal that the flowerlike ZnO has a wurtzite structure and is composed of numerous aggregated single-crystalline ZnO nanorods with a diameter of about 60nm. Having fabricated gas sensors based on the pure and Pd-sensitized flowerlike ZnO, we find that the Pd-sensitized sensor exhibits a response of 45.7–50ppm NH3 at 210°C, which is about 8 times higher than that of pure ZnO at the optimal operating temperature of 350°C. The enhanced NH3-sensing performance demonstrates that the significant decrease in optimal operating temperature and the distinct increase in response are attributed to the sensitization effect of Pd.
    Sensors and Actuators B Chemical 08/2011; 156(1):395-400. DOI:10.1016/j.snb.2011.04.064 · 3.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In recent years, metal hollow nanostructures are intriguing to be synthesized and studied because they exhibit unique surface plasmonic properties. Although many methods for tuning the surface plasmonic absorption peaks of silver nanostructures have been reported, it still remains a great challenge to produce hollow Ag nanostructure with controllable surface plasmon resonance (SPR) via a facile method. In this paper, triangular Au–Ag nanoframes were successfully fabricated using triangular silver nanoplates as templates, through galvanic replacement reaction between the silver nanoplates and HAuCl4, exhibiting tuneable SPR response from visible (605nm) to near-infrared region (1,235nm). KeywordsTriangular gold–silver nanoframes–Surface plasmon resonance–Triangular silver nanoplates–Hollow nanostructures
    Plasmonics 06/2011; 6(2):241-244. DOI:10.1007/s11468-010-9194-z · 2.74 Impact Factor