Growth of porous single-crystal Cr2O3 in a 3-D mesopore system

Jiang, Kun; Zhang, Bin; Yue, Bin; Ren, Yu; Liu, Shixi; Yan, Shaomin; Dickinson, Calum; Zhou, Wuzong; He, Heyong

doi:10.1039/b512080b

Cited by 138 publications

(114 citation statements)

References 23 publications

(20 reference statements)

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“…5b), which is the same as that reported in literatures. [31,46,47] This result suggests that the CrO 3 precursor can transform to Cr 2 O 3 upon reduction at 700 8C in air. After high-temperature nitridation under ammonia gas, the XRD pattern is totally changed and all diffractions are attributed to CrN crystals with face-centered cubic structure (JCPDS: 65-2899).…”

Section: Mesoporous Crn Materialsmentioning

confidence: 69%

Synthesis of Self‐Supported Ordered Mesoporous Cobalt and Chromium Nitrides

Shi

Wan

Zhang

et al. 2008

Adv Funct Materials

102

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Herein, we demonstrate an ammonia nitridation approach to synthesize self‐supported ordered mesoporous metal nitrides (CoN and CrN) from mesostructured metal oxide replicas (Co3O4 and Cr2O3), which were nanocastly prepared by using mesoporous silica SBA‐15 as a hard template. Two synthetic routes are adopted. One route is the direct nitridation of mesoporous metal oxide nanowire replicas templated from SBA‐15 to metal nitrides. By this method, highly ordered mesoporous cobalt nitrides (CoN) can be obtained by the transformation of Co3O4 nanowire replica under ammonia atmosphere from 275 to 350 °C, without a distinct lose of the mesostructural regularity. Treating the samples above 375 °C leads to the formation of metallic cobalt and the collapse of the mesostructure due to large volume shrinkage. The other route is to transform mesostructured metal oxides/silica composites to nitrides/silica composites at 750–1000 °C under ammonia. Ordered mesoporous CrN nanowire arrays can be obtained after the silica template removal by NaOH erosion. A slowly temperature‐program‐decrease process can reduce the influence of silica nitridation and improve the purity of final CrN product. Small‐angle XRD patterns and TEM images showed the 2‐D ordered hexagonal structure of the obtained mesoporous CoN and CrN nanowires. Wide‐angle XRD patterns, HRTEM images, and SAED patterns revealed the formation of crystallized metal nitrides. Nitrogen sorption analyses showed that the obtained materials possessed high surface areas (70–90 m2 g−1) and large pore volumes (about 0.2 cm3 g−1).

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Section: Mesoporous Crn Materialsmentioning

confidence: 69%

Synthesis of Self‐Supported Ordered Mesoporous Cobalt and Chromium Nitrides

Shi

Wan

Zhang

et al. 2008

Adv Funct Materials

102

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“…The synthesis of mesoporous transition metal oxides via the hard-templating route can deliver materials with highly ordered pore structures and highly crystalline walls, as well as good thermal stability [1][2][3][4][5][6][7]. Such materials exhibit unique optical, magnetic, and electrical properties [8][9][10].…”

Section: Introductionmentioning

confidence: 98%

Ordered Crystalline Mesoporous Oxides as Catalysts for CO Oxidation

et al. 2009

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Crystalline mesoporous metal oxides have attracted considerable attention recently, but their catalytic applications have rarely been studied. In this work, a series of crystalline three-dimensional mesoporous metal oxides (i.e., CeO ) were prepared using the mesoporous silica KIT-6 as a hard template. These ordered mesoporous metal oxides with highly crystalline walls were characterized by PXRD, TEM, N 2 adsorption and evaluated as CO oxidation catalysts. These mesoporous materials, except for mesoporous Fe 2 O 3 , exhibit much higher catalytic activities than their bulk counterparts. In particular, mesoporous Co 3 O 4 , b-MnO 2 , and NiO show appreciable CO oxidation activity below 0°C, and the catalytic activities of mesoporous b-MnO 2 , and NiO are even higher than those of their nanoparticulate counterparts with large surface areas. b-MnO 2 is particularly interesting because it combines low cost and low toxicity with high activity (T 50 = 39°C).

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“…From low-angle XRD patterns in Fig. 1B, all the samples showed the (211) and (220) diffraction peaks, which were characteristic of a cubic (Ia3d) symmetry of the pore systems, indicating a high degree of ordering of the mesoporous materials [15,16].…”

Section: Resultsmentioning

confidence: 98%