The catalytic activity of unsupported CeVO4 solid was investigated in ammonia-SCR at various NO/NOx ratio. CeVO4 structure was obtained from a straightforward hydrothermal synthesis route under mild conditions and then stabilized after ageing in wet atmosphere at 600 °C. The influence of pH measured after the hydrothermal treatment could be a crucial parameter to get optimal bulk and surface properties. The evolution of intrinsic catalytic activity was compared with regards to bulk and surface properties extracted from extensive characterization. The stabilization of V5+ in CeVO4 structure during NH3-SCR reactions was observed even after thermal aging at high temperature. This opens new perspectives for vanadium-based catalysts in mobile sources applications.