Synthesis, Characterization, and Testing of A12O3 Supported Tungsten Carbide as a Catalyst for the Reverse Water Gas Shift Reaction
Technical Report,07 Aug 2018,07 Aug 2019
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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The conversion of CO2 to CO via the reverse water gas shift RWGS reaction is often envisioned as the first step in the large scale transformation of CO2 into value-added hydrocarbons. Accordingly, low cost and highly selective RWGS catalysts are desirable materials for sustainable CO2 utilization. Here, we describe synthesis, characterization, and performance evaluation of unpromoted, Na-promoted, and K-promoted tungsten carbide WC RWGS catalysts, supported on porous Al2O3. Scanning electron microscopy reveals significant differences in the distribution of the alkali-promoted WC catalysts, suggesting that the alkali metals serve as structural promoters, while X-ray photoelectron spectroscopy indicates slight differences in the electronic structure of the K-promoted WC. Performance data for the RWGS reaction at 300 and 350 deg C shows all catalysts are active, with the alkali promoted catalysts demonstrating improved CO selectivity. Of the three catalysts, the highest CO yield is achieved using the K-promoted WC, demonstrating that K-WC can serve as a low cost, active, and selective RWGS catalyst. Additionally, we prepared and tested unpromoted W and W2C catalysts supported on Al2O3 to compare to the well characterized WC catalysts. These materials were also active for RWGS, but were less active and selective than the supported WC catalysts.
- Physical Chemistry
- Inorganic Chemistry