The activated carbon was pretreated by different concentrations of HNO3 solution to prepare Ni/AC catalysts with different oxygen contents. The change of the oxygen-containing groups during the carbonylation was traced using an instrument named Micro-Fluidized Bed Reactor Analyst-Particle (MFBRA-P), which can sample out catalyst particles on-line at specific time interval during the reaction. The online sampled catalysts were characterized by N-2-sorption, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), transmission electron microscope (TEM), temperature programmed desorption (TPD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). It was found that catalysts with smaller amount of oxygen-containing groups had higher initial activity and higher deactivation rate, which was consistent with the accumulation rate of oxygen-containing groups. High content of oxygen suppressed the accumulation of oxygen-containing carbonaceous deposits, resulting in better catalytic stability for carbonylation. (C) 2016 Elsevier B.V. All rights reserved.