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Catalytic Activity Control via Crossover between Two Different Microstructures
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2017-09-21 00:00:00 , DOI: 10.1021/jacs.7b05476
Yuheng Zhou 1 , Yihan Zhu 2 , Zhi-Qiang Wang 3 , Shihui Zou 1 , Guicen Ma 1 , Ming Xia 1 , Xueqian Kong 1 , Liping Xiao 1 , Xue-Qing Gong 3 , Jie Fan 1
Affiliation  

Metal nanocatalysts hold great promise for a wide range of heterogeneous catalytic reactions, while the optimization strategy of catalytic activity is largely restricted by particle size or shape control. Here, we demonstrate that a reversible microstructural control through the crossover between multiply twinned nanoparticle (MTP) and single crystal (SC) can be readily achieved by solvent post-treatment on gold nanoparticles (AuNPs). Polar solvents (e.g., water, methanol) direct the transformation from MTP to SC accompanied by the disappearance of twinning and stacking faults. A reverse transformation from SC to MTP is achieved in nonpolar solvent (e.g., toluene) mixed with thiol ligands. The transformation between two different microstructures is directly observed by in situ TEM and leads to a drastic modulation of catalytic activity toward the gas-phase selective oxidation of alcohols. On the basis of the combined experimental and theoretical investigations of alcohol chemisorption on these nanocatalysts, we propose that the exposure of {211}-like microfacets associated with twin boundaries and stack faults accounts for the strong chemisorption of alcohol molecules on MTP AuNPs and thus the exceptionally high catalytic activity.

中文翻译:

通过两个不同的微结构之间的交叉控制催化活性

金属纳米催化剂对于广泛的非均相催化反应具有广阔的前景,而催化活性的优化策略在很大程度上受到粒度或形状控制的限制。在这里,我们证明了通过在金纳米颗粒(AuNPs)上进行溶剂后处理,可以很容易地实现通过双晶纳米颗粒(MTP)和单晶(SC)之间交叉的可逆微结构控制。极性溶剂(例如水,甲醇)指导从MTP到SC的转化,伴随着孪生和堆积缺陷的消失。在与硫醇配体混合的非极性溶剂(例如甲苯)中,可以实现从SC到MTP的反向转化。通过原位TEM直接观察到两个不同微观结构之间的转化,并导致对醇气相选择性氧化催化活性的急剧调节。在酒精化学吸附在这些纳米催化剂上的实验和理论研究相结合的基础上,我们建议与双边界和堆垛层错相关的{211}样微面的暴露说明了醇分子在MTP AuNPs上的强烈化学吸附。极高的催化活性。
更新日期:2017-09-21
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