Catalytic enhancement of water gas shift reaction with Cu/ZnO/ZSM-5: Overcoming challenges of CO2 and H2 rich feeds

Water gas shift (WGS) reaction commonly converts CO to CO 2 using H 2 O and produces H 2 and CO 2 in a catalytic fixed bed reactor. This study aims to develop a Cu/ZnO/ZSM-5 catalyst loaded in water gas shift reactor for converting typical synthesis gas produced from dry reforming of methane (DRM) at medium temperature shift (MTS, 200–350 o C) conditions and for preventing reverse reaction due to high feed concentrations of CO 2 and H 2 . The Cu/ZnO/ZSM-5 catalyst was prepared by impregnation method with lower Cu metal loading of 5, 10, and 15 wt%, respectively, compared to commercial catalysts. The synthesized catalyst was characterized using XRF , XRD , SEM, H 2 -TPR, NH 3 -TPD, and TGA . The catalyst activity and stability for the WGS reaction were tested in the fixed bed reactor at atmospheric pressure and temperature of 325 °C. The experimental results show that CO conversion increases with increasing Cu loading. The 15 wt% Cu/ZnO/ZSM-5 catalyst showed the best results with a CO conversion of 35% and a yield of H 2 of 36% and showed good stability for 32 h. Based on the TGA, the 15 wt% Cu/ZnO/ZSM-5 catalyst forms a 0.04 g carbon/g catalyst, which is much lower when compared to commercial catalyst (0.105 g carbon/g catalyst). The relative activity of the synthesized catalyst indicates 2.4 times better when compared to commercial catalysts. High concentrations of H 2 and CO 2 in the feed may initiate side reactions, including reverse WGS, methanation, and carbon formation, which will decrease H 2 yield. • Cu/ZnO/ZSM-5 catalyst boosts CO conversion to 35% at 325 °C in WGS reaction. • 15 wt% Cu/ZnO/ZSM-5 achieves 36% H2 yield with 32-h stability in WGS. • Carbon formation is 0.04 g/g, lower than commercial catalyst's 0.105 g/g.