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

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.