(320g) Reverse Water Gas Shift (RWGS) Reaction-Selective and One-Pot Chemical Vapor Deposition (OP-CVD)-Derived Optimized CuOx/CeO2 Catalyst

Reducing the levels of carbon dioxide (CO₂), a greenhouse gas, is critically important for rebuilding the current ecological system for a sustainable environment. Utilization of CO₂ by hydrogenation, H₂ as future clean source, via reverse water gas shift (RWGS) reaction seems a viable option [1]. The thermodynamically unfavorable and endothermic nature of RWGS reaction necessitates a selective catalytic reaction (SCR) for progress under mild conditions [2]. To serve this purpose, supported catalysts provide adequate active sites and high surface utilization. This study focuses on ceria supported copper oxide (CuO_x/CeO₂) catalysts to overcome the challenges faced by existing synthesis technologies, viz. severe agglomerations, inaccurate Cu loading, non-availability of active sites and surface, and ineffective metal support interaction (MSI), to achieve high catalytic performance. An optimized CuO_x/CeO₂ catalyst was developed by one-pot chemical vapor deposition (OP-CVD) method with deposition and calcination as major controlling steps. A varied conditions for weight loading of Cu (0.5 – 7 wt%), deposition (155 – 180 ^oC) and calcination (400 – 700 ^oC) were used. The prepared catalysts were characterized using BET-PSD, ICP-OES, CO chemisorption, XRD, STEM-EDS, and Raman spectroscopy to understand their structure and physical properties. The RWGS reaction activity results for 3% CuO_x/CeO₂, prepared at deposition: 155 ^oC and calcination: 400 ^oC, in CO₂:H₂ reactant feed of 1:1 (126,000 ml h^-1 gcat^-1) showed superior activity and was able to achieve equilibrium CO₂ conversion at ~300 ^oC and thereafter (Figure1). A time on stream (TOS) analysis for 108 h proved the catalyst stability under long working conditions, and in-situ XRD proved catalysts’ structural stability. All the CuO_x/CeO₂ catalysts showed 100% selectivity for RWGS (only CO), without any methanation side reaction (Figure1). Thus, the work effectively contributed to the development of optimal-synthesized and durable CuO_x/CeO₂ catalyst by OP-CVD to achieve high RWGS activity with clear structural approach.