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The selective hydrogenation of acetylene is a vital process to for the purification of crude ethylene in petroleum industry. Achieving high activity and selectivity simultaneously over Ni-based catalysts is still challenging. Herein, a partial encapsulation strategy is proposed by fabricating carbon-encapsulated Ag nanoparticles and un-encapsulated Ni nanoparticles on Al 2 O 3 surface (Ni-Ag@C/Al 2 O 3) toward the enhanced selectivity without loss of activity. In particular, the Ni-Ag@C/Al 2 O 3 exhibits higher ethylene selectivity of 81% at the complete acetylene conversion along with excellent stability for 30-h, in sharp with the Ni/Al 2 O 3 (6%) and Ni-Ag/Al 2 O 3 (54%) catalyst. The enhanced selectivity is attributed to the promotion of hydrogen spillover by the carbon species on Al 2 O 3 surface and the inhibition of oligomer formation by a steric hindrance formed by the carbon layer on the Ag surface. This study provides a new structural design avenue of bifunctional bimetallic catalyst for selective hydrogenation reaction. [Display omitted] • Separated Ag@C nanoparticles and Ni nanoparticles were fabricated on Al 2 O 3 surface. • High activity and selectivity were achieved simultaneously over Ni-Ag@C/Al 2 O 3. • The high activity is due to that the non-encapsulation of Ni with carbon layer. • Hydrogen spillover was enhanced over Ni-Ag@C/Al 2 O 3 by the carbon species on Al 2 O 3. • The carbon layer suppresses oligomer formation, thus resulting in high stability. [ABSTRACT FROM AUTHOR]