Controlled template removal from nanocast La0.8Sr0.2FeO3 for enhanced CO2 conversion by reverse water gas shift chemical looping

Iron-Poor Ferrites for Low-Temperature CO2 Conversion via Reverse Water–Gas Shift Thermochemical Looping

“…Improvement of the reaction kinetics is necessary for commercialization and is beyond the scope of this study. However, we note that, as far as we are aware, the RWGS-CL metal oxide with the highest reported experimental CO yield at 600 °C in the literature achieves a CO yield of 86 mL CO/ g MOd x /cycle, 25 whereas Fe 0.35 Ni 0.65 O x /ZrO 2 achieves a similar yield (80 mL CO/g MOd x /cycle) at 100 °C lower reaction temperature. We also note that the observed CO yield of Fe 0.35 Ni 0.65 O x is stable at 80 mL CO/g-MO x for up to 40 cycles (Figure 3a).…”

“…CO yields from chemical looping CO 2 oxidation but with CH 4 as the reducing agent instead of H 2 are also included for comparison purposes in Figure 4a; reduction with CH 4 requires higher reaction temperatures and produces carbon as a byproduct. CO yields of reported metal oxides generally increase with temperature in a loosely exponential trend, with the highest reported experimental CO yields being ∼26 mL CO/g MOd x /cycle at 550 °C, 20 ∼86 mL/ CO/g MOd x /cycle at 600 °C, 25 and ∼220 mL CO/g MOd x /cycle at 650 °C, 27 albeit with differing H 2 and CO 2 feed gas concentrations and reactor setups. While we observe that our Fe 0.35 Ni 0.65 O x achieves a CO yield (80 mL CO/g MOd x /cycle) at 100 °C lower reaction temperature than an RWGS-CL metal oxide of similar yield (∼86 mL/ CO/g MOd x /cycle at 600 °C25 ), we note that difficult to directly compare CO yields across different studies since flow conditions, reactor designs, sample mounting, and experimental parameters can differ significantly.…”

“…Previously reported RWGS-CL metal oxides with high CO yields include supported Fe 2 O 3 , 15−19 lanthanum-based perovskites, 20−25 and Mn-and Co-doped ferrites. 26,27 CO yield per gram of metal oxide per cycle increases with increasing reaction temperature (faster kinetics), with the highest reported yields being ∼220 mL CO/g MOx / cycle at 650 °C by Xiao and co-workers, 27 ∼86 mL/ CO/ g MOx /cycle at 600 °C by Lee et al, 25 and ∼26 mL CO/g MOx / cycle at 550 °C by Kuhn and co-workers, 20 albeit all experiments are performed with differing H 2 and CO 2 feed gas concentrations. Additionally, both Fan and Li (and coworkers) have researched using CH 4 , coal, natural gas, and other abundant and affordable carbonaceous fuels instead of hydrogen as reducing agents at the expense of higher required operating temperatures and challenges related to coking.…”

Emerging natural and tailored perovskite-type mixed oxides–based catalysts for CO2 conversions

“…However, it could suffer the effect of catalyst sintering deactivation at elevated temperatures. Therefore, improving the catalytic activity at lower temperatures or adopting catalysts with higher temperature stability is the main strategy to realize the industrialization of the RWGS reaction (Kopac et al, 2020;Yang et al, 2020;Lim et al, 2021b;Jo et al, 2022). In any case, green hydrogen is needed for the RWGS when this process is envisaged as a greenhouse gas conversion route (Nityashree et al, 2020).…”

“…For example, the researchers also developed the effect of using various supports (CeO 2 , Al 2 O 3 , SiO 2 , TiO 2 , and ZrO 2 ) in combination with perovskite oxides for RWGS (Hare et al, 2018;Hare et al, 2019b). It is worth noting that the synthesis method of perovskite also influences the RWGS performance (Lim et al, 2021b;Jo et al, 2022).…”