Low-temperature carbon dioxide conversion via reverse water-gas shift thermochemical looping with supported iron oxide

Carbon dioxide utilization via the reverse water-gas shift (RWGS) reaction is a potentially scalable method to mitigate rising global carbon dioxide emissions if high carbon monoxide yields and reac-tion rates can be achieved at low reaction temperatures. Iron oxide (Fe2O3) has been extensively studied as a chemical looping mate-rial in RWGS, but nearly all studies were performed at high temper-atures, where sintering and deactivation occur. Here, we investi-gate Fe2O3 as an RWGS chemical looping metal oxide at low reaction temperatures (500 degrees C for both oxidation and reduction steps) and find that a direct, reversible, and stable metal/oxide phase transition results in a high carbon monoxide yield of 386 mL CO/g-Fe2O3/cycle. The measured carbon monoxide yield remains relatively stable for 350 redox cycles or 12.1 days on stream. The affordability and abundance of Fe2O3, the high carbon monoxide yield, and its extended time-on-stream without substan-tial performance degredation makes Fe2O3 a RWGS chemical loop-ing metal oxide with a promising chance of commercialization.