Methane dry reforming with CO2 over ceria supported Ni catalyst prepared by reverse microemulsion synthesis

•Oxygen mobility exhibited a major role in the decrease of carbon deposition.•40% Ni/CeO2 catalyst prepared by microemulsion showed higher catalytic activity.•20% Ni/CeO2 catalyst exhibited shell-like carbon deposits.•Whisker-like carbon species were exhibited by 40% Ni/CeO2 and 80% Ni/CeO2.