Efficient CO 2-utilization is key to limit global climate change. Carbon monoxide, which is a crucial feedstock for chemical synthesis, can be produced by splitting CO 2. However, existing thermochemical routes are energy-intensive requiring high operating temperatures. We report a Hybrid Redox Process (HRP) involving CO 2-to-CO conversion using a lattice oxygen-deprived redox catalyst at relatively low temperatures (<700 °C). The lattice oxygen of the redox catalyst, restored during CO 2-splitting, is subsequently used to convert methane to syngas. Operated at temperatures significantly lower than a number of industrial waste heat sources, this cyclic redox process allows for efficient waste heat-utilization to convert CO 2. To enable the low temperature operation, we report lanthanum modified ceria (1:1 Ce: La) promoted by rhodium (0.5 wt. %) as an effective redox catalyst. Near-complete CO 2 conversion with a syngas yield of up to 83% at low temperatures were achieved using Rh-promoted LaCeO 4-x. While La improves low-temperature bulk redox properties of ceria, Rh considerably enhances the surface catalytic properties for methane-activation. Density Functional Theory calculations further illustrate the underlying functions of La-substitution. The highly effective redox catalyst and HRP scheme provide a potentially attractive route for chemical production using CO 2 , industrial waste heat, and methane, with appreciably lowered CO 2 emissions.

No abstract

Selective hydrogen combustion (SHC) in the presence of light hydrocarbons was demonstrated with a series of Mn‐containing mixed oxide redox catalysts in the context of a chemical looping‐oxidative dehydrogenation scheme. Unpromoted and 20 wt % Na2WO4‐promoted Mg6MnO8, SrMnO3, and CaMnO3 exhibited varying SHC capabilities at temperatures between 550 and 850°C. Reduction temperature of unpromoted redox catalysts increased in the order Mg6MnO8 < SrMnO3 < CaMnO3. Promotion with 20 wt % Na2WO4 resulted in more selective redox catalysts capable of high‐temperature SHC. XPS analysis revealed a correlation between suppression of near‐surface Mn and SHC selectivity. Na2WO4/CaMnO3 showed steady SHC performance (89% H2 conversion, 88% selectivity) at 850°C over 50 redox cycles. In series with a Cr2O3/Al2O3 ethane dehydrogenation catalyst, Na2WO4/CaMnO3 combusted 84% of H2 produced while limiting COx yield below 2%. The redox catalysts reported can be suitable for SHC in a cyclic redox scheme for the production of light olefins from alkanes. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3141–3150, 2018

No abstract

No abstract

This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

No abstract

Promoted hexaaluminate redox catalysts achieved excellent olefin yield while allowing autothermal redox oxidative cracking of naphtha with low COx formation.