Effect of catalytic site position: Nickel nanocatalyst selectively loaded inside or outside carbon nanotubes for methane dry reforming

► Ni nanoparticles were selectively loaded inside or outside CNTs. ► Ni inside CNTs showed higher activity than Ni outside CNTs for methane dry reforming. ► Ni inside CNTs was more stable than Ni outside CNTs for methane dry reforming. ► Enhanced catalytic performance was attributed to the confinement of CNTs channels.