Ni-Phosphide catalysts as versatile systems for gas-phase CO2 conversion: Impact of the support and evidences of structure-sensitivity

We report for the first time support dependent activity and selectivity of Ni-rich nickel phosphide catalysts CO2 hydrogenation. New hydrogenation are needed to commercialise reverse water–gas shift reaction (RWGS) which can feed captured carbon as feedstock traditionally fossil fuel-based processes, well develop flexible power-to-gas schemes that synthesise chemicals on demand using surplus renewable energy CO2. Here we show Ni2P/SiO2 is a highly selective catalyst RWGS, producing over 80% CO in full temperature range 350–750 °C. This indicates high degree suppression methanation by formation, Ni known their activity. shown not simply be site blocking effect, but arise from formation new more active RWGS. When supported Al2O3 or CeAl, dominant phase synthesized Ni12P5. These Ni12P5 behave very differently compared Ni2P/SiO2, at low temperatures with switchover RWGS higher (reaching approaching thermodynamic equilibrium behaviour). switchable interesting applications where flexibility distributed production desirable. Both Ni12P5/Al2O3 Ni12P5/CeAl excellent stability 100 h stream, they switch between reactions 50–70% conversion. Catalysts characterized before after via X-ray Diffraction (XRD), Photoelectron Spectroscopy (XPS), temperature-programmed reduction oxidation (TPR, TPO), Transmission Electron Microscopy (TEM), BET surface area measurement. After reaction, shows emergence crystalline while both Ni3P phase. While stable latter demonstrated extended testing, this enrichment all dynamic nature during operation. Moreover, it demonstrates play key role determining towards CH4.