A Surface Defect-Promoted Ni Nanocatalyst with Simultaneously Enhanced Activity and Stability

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• 作者：Shan He ; Changming Li ; Hao Chen ; Dangsheng Su ; Bingsen Zhang ; Xingzhong Cao ; Baoyi Wang ; Min Wei ; David G. Evans ; Xue Duan
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：April 9, 2013
• 年：2013
• 卷：25
• 期：7
• 页码：1040-1046
• 全文大小：446K
• 年卷期：v.25,no.7(April 9, 2013)
• ISSN：1520-5002

文摘

How to achieve supported metal nanocatalysts with simultaneously enhanced activity and stability is of vital importance in heterogeneous catalysis and remains a challenging goal. In this work, a surface defect-promoted Ni nanocatalyst with a high dispersion and high particle density embedded on a hierarchical Al₂O₃ matrix was fabricated via a facile method involving an in situ reduction process, which exhibits excellent activity and stability simultaneously for the reaction of CO₂ methanation. HRTEM, HAADF-STEM, EXAFS, and positron annihilation spectroscopy demonstrate the existence of abundant surface vacancy clusters that serve as active sites, accounting for the significantly enhanced low-temperature activity of the supported Ni nanoparticles. In addition, the anchoring effect from the support gives rise to a high reaction stability, without sintering and/or aggregation of active species during long-term use.

Keywords:

Ni nanocatalyst; surface defect; low-temperature activation; CO₂ methanation; layered double hydroxides