Solar-assisted two-stage catalytic membrane reactor for coupling CO2 splitting with methane oxidation reaction

A two-stage catalytic membrane reactor (CMR) that couples CO splitting with methane oxidation reactions was constructed based on an oxygen-permeable perovskite asymmetric membrane. The asymmetric membrane comprises a dense SrFeTaO (SFT) separation layer and a porous Sr(FeTa)CuO (SFTC) catalytic layer. In the first stage reactor, a CO splitting reaction (CDS: 2CO→2CO+O) occurs at the SFTC catalytic layer. Subsequently, the O product is selectively extracted through the SFT separation layer to the permeated side for the methane combustion reaction (MCR), which provides an extremely low oxygen partial pressure to enhance the oxygen extraction. In the second stage, a Sr(FeTa)NiO (SFTN) catalyst is employed to reform the products derived from MCR. The two-stage CMR design results in a remarkable 35.4% CO conversion for CDS at 900 °C. The two-stage CMR was extended to a hollow fiber configuration combining with solar irradiation. The solar-assisted two-stage CMR can operate stably for over 50 hours with a high hydrogen yield of 18.1 mL min cm. These results provide a novel strategy for reducing CO emissions, suggesting potential avenues for the design of the high-performance CMRs and catalysts based on perovskite oxides in the future.