▎ 摘　　要

Ni-0@graphene nanocomposites were prepared via a solvothermal method and used as the catalysts for the viscosity reduction of extra heavy crude oil. Higher graphene content in Ni-0@graphene nanocomposite has an adverse effect on its catalytic activity. The addition of tetralin and higher reaction temperature can obviously promote the catalytic activity. The catalyst accompanied by hydrogen donor can attain a viscosity reduction rate of 84.3% after the catalytic reaction under 280 degrees C for 24h and reduce the viscosity of crude oil from 174,219 to 27,352mPa s (measured at 50 degrees C).