Coupling CO2 utilization and NO reduction in chemical looping manner by surface carbon

Abstract Carbon deposits typically enforce shutdowns of chemical reactors to periodically regenerate their active materials, a continuous challenge for industry and scientists alike. This downside can however be turned to benefit by utilizing carbon’s reductive power. Here, we integrate dry reforming of methane (DRM) and selective reduction of nitric oxide (SRN) in a novel chemical looping process, coupled by the periodic deposition and removal of surface carbon, which participates in both reactions. Carbon formed on the catalyst during dry reforming is subsequently used as reductant for nitric oxide (NO) conversion into N2, hence not only achieves stable CO2 utilization and NO reduction with cyclic catalyst regeneration, but also reduces the consumption of valuable energy resources demanded by NO removal. In contrast to co-feeding all reactants in a single step, the inherent temporal-spatial separation of reactions in chemical looping allows for complete conversion of carbon and NO, ensuring a higher exergetic efficiency (70 % more efficient). Also, adaptation of the relative duration of the DRM and SRN steps to the conditions of the CO2 and NO industrial point sources allows to account for the differences in supply of carbon and NO, offering an attractive strategy for selective catalytic reduction of NO with greenhouse gases rather than NH3.