The combined method of non-thermal plasma injection and 3%CeO2-WO3/TiO2 catalysis system was proposed to enhance Hg oxidation in flue gas. Compared with the plasma system, the combined system had excellent oxidation performance. Approximately 86.6% of Hg-0 was oxidized and energy yield reached 32.9 mu g kJ(-1) at 2.6 J L-1 and 110 degrees C. The combined system widened the temperature windows of CeO2-WO3/TiO2 catalyst (80-300 degrees C), showed good resistance to H2O and SO2, and also overcame the inhibitory effect of NO on Hg oxidation in the plasma system center dot NH3 inhibited the Hg-0 oxidation; however, the coexistence of NO with NH3 significantly mitigated the inhibition. In the combined system, the CeO2-WO3/TiO2 catalyst could catalytically decompose the ozone generated by gas discharge, and increased the production of high adsorbed active oxygen, which was favorable for Hg-0 oxidation process. The Hg oxidation process followed the homogeneous reaction mechanism and the Mars-Maessen mechanism in NTP injection system and CeO2-WO3/TiO2 system, respectively. (C) 2017 Elsevier B.V. All rights reserved.