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Hierarchical flowerlike metal/metal oxide nanostructures derived from layered double hydroxides for catalysis and gas sensing
- Wang, Xiao, Cao, Ruya, Zhang, Shouwei, Hou, Peiyu, Han, Ruxia, Shao, Minghui, Xu, Xijin
- Journal of materials chemistry A 2017 v.5 no.45 pp. 23999-24010
- active sites, aluminum, catalysts, catalytic activity, coal, cobalt, dispersions, ethanol, hydroxides, nanosheets, p-nitrophenol, pollution
- The development of advanced functional materials for catalytic reduction and gas sensing is one of the most important issues for the detection and prevention of environmental pollution. Herein, hierarchical peony-like metal/metal oxide (Co/Al₂O₃ and Co₃O₄/Al₂O₃) composites assembled with uniform nanosheets were successfully synthesized using CoAl layered double hydroxides as self-sacrificial templates. Co/Al₂O₃ composites exhibited high surface dispersions and low metal–support interactions which can be confirmed by a series of structure and morphology characterizations. With the above advantages, Co/Al₂O₃ composites showed remarkable catalytic ability and stability towards 4-nitrophenol (4-NP) reduction with a nearly 100% conversion within 3 minutes and a conversion efficiency over 98% after 10 successive recycles. After that, Co/Al₂O₃ composites with different Co/Al ratios were fabricated to investigate the optimal Co content in the catalytic reduction of 4-NP. The results indicated that when the Co/Al ratio reaches 4 : 1, the fabricated composites have the best catalytic reduction abilities. Furthermore, the fabricated Co₃O₄/Al₂O₃ gas sensors exhibited a superior response time of 1 s towards 50 ppm ethanol with a sensing response of 8.9. These excellent catalytic reduction and gas sensing abilities could be attributed to the unique peony-like hierarchical structure which could provide large surface areas and abundant active sites. More importantly, this work provided a new synthesis strategy to design materials with enhanced catalytic reduction and gas sensing abilities, which will be beneficial to the development of highly effective catalysts and gas sensing materials.