Exploring the Challenges of Calcium Looping Integrated with Methane Bireforming for Enhanced Carbon Capture and Utilization.

The urgent need to mitigate greenhouse gas emissions and combat climate change has driven research in carbon capture and utilization (CCU) technologies. Among these, calcium looping (CaL) has emerged as a prominent candidate for CO 2 capture. This study aimed to explore the novel integration of CaL with methane bireforming (BRM) using CaO-Ni/CeO 2 as dual-function material (DFM) and investigated the challenges and opportunities associated with the process. Implementing a calcium looping-bireforming (CaL-BRM) process revealed distinct differences compared to methane dry reforming (DRM). Notably, methane conversion occurred at higher temperatures, likely due to competition with the formation of Ca(OH) 2 . Meanwhile, the conversion of CO 2 was delayed, possibly because hydroxide species on the CaO surfaces hindered the availability of CO 2 for methane reforming. To address these challenges, Ni/CeO 2 and CaO-Ni/CeO 2 catalysts were employed in conventional catalytic gas-phase BRM and methane steam reforming (SRM) reactions. The results demonstrated that the presence of CaO significantly influenced BRM efficiency due to the Ca(OH) 2 formation, as was evident by the results of the characterization on the postreaction catalysts and the parallel study of SRM. This study contributes valuable insights into the feasibility and potential of CaL-BRM, advancing the development of sustainable CCU technologies.