The proton conductors Sr3CaZr0.5Ta1.5O8.75 (SCZT), BaCe0.9Y0.1O2.95 (BCY10) and Ba3Ca1.18Nb1.82O8.73(BCN18) have been shown to be active heterogeneous catalysts for the reverse water gas shift (RWGS) reaction. Catalytic characterisation was conducted in a quartz fixed-bed reactor with a silica fritted disk and monitored by a gas chromatograph. X-ray diffraction and TGA+MS were used to characterise samples before and after catalytic tests. BCY10 reaches 45% CO2 conversion at 900 degrees C, 3% more than BCN18 (42% total conversion) at 900 degrees C. SCZT reaches 36% CO2 conversion at 900 degrees C, but has the lowest conversion onset temperature and activation energy of the materials studied. (c) 2007 Elsevier B.V. All rights reserved.