Influence of Ni support on ICCU-RWGS

The following work reported the use of different supports for Ni-based catalysts, which were physically mixed with CaO for ICCU-RWGS.

“The ICCU-RWGS performance using Ni/support-CaO bifunctional combined materials (BCMs) with various supports (e.g. ZrO2, TiO2, CeO2 and Al2O3) are shown in Fig. 7. Here Ni particles were used as active catalytic sites, and CaO played as the CO2 adsorbent. A typical ICCU-RWGS process mainly included two steps, one was CO2 adsorption from a diluted CO2 source (e.g. 20% CO2/N2), and another was hydrogenation of the captured CO2. The above two steps were isothermally operated by switching the inlet gas between 20% CO2/N2 and 5% H2/N2. The SiO2/CaO was used as a blank benchmark material to demonstrate the ICCU-RWGS performance with bare inert support compared to active Ni metal over active supports. To reveal the optimal support for the ICCU-RWGS process, various Ni/support-CaO bifunctional combined materials were evaluated at 550–750 °C.”


Fig. 7. Integrated CO2 capture and RWGS performance of various Ni/support-CaO BCMs: (a) CO2 conversion; (b) CO selectivity; (c) CO yield and (d) C1 species (CO2 + CO + CH4) yield.”

“As shown in Fig. 7a and 7c, the CO2 conversions and CO yields of various Ni/support-CaO BCMs followed the decreasing order: Ni/CeO2-CaO > Ni/TiO2-CaO > Ni/ZrO2-CaO > Ni/Al2O3-CaO. All of the Ni/support-CaO BCMs exhibited excellent CO selectivity (∼100%) over the investigated temperature range. The Ni/Al2O3-CaO showed only a comparable performance with SiO2-CaO in terms of CO2 conversion and CO yield, indicating the poor catalytic activities of nonreducible NiAl2O4 spinel (Fig. 5a). However, Ni/TiO2-CaO with NiTiO3 spinel achieved much high CO2 conversion compared to Ni/Al2O3-CaO owing to the better spinel reducibility. Although there was no spinel formation, Ni/CeO2-CaO outperforms Ni/ZrO2-CaO in relation to CO2 conversion and CO yield. For example, Ni/CeO2-CaO and Ni/ZrO2-CaO achieved 56.1% and 34.0% for CO2 conversion and 2.7 and 1.1 mmol g−1 for CO yield at 650 °C, respectively.”



Leave a Comment