Solar-Driven Thermochemical Splitting of CO₂ and In Situ Separation of CO and O₂ across a Ceria Redox Membrane Reactor.

ABSTRACT: Splitting CO₂ with a thermochemical redox cycle utilizes the entire solar spectrum and provides a favorable path to the synthesis of solar fuels at high rates and efficiencies. However, the temperature/pressure swing commonly applied between reduction and oxidation steps incurs irreversible energy losses and severe material stresses. Here, we experimentally demonstrate for the first time the single-step continuous splitting of CO₂ into separate streams of CO and O₂ under steady-state isothermal/isobaric conditions. This is accomplished using a solar-driven ceria membrane reactor conducting oxygen ions, electrons, and vacancies induced by the oxygen chemical potential gradient. Guided by the limitations imposed by thermodynamic equilibrium of CO₂ thermolysis, we operated the solar reactor at 1,600°C, 3·10^-6 bar [Formula: see text] and 3,500 suns radiation, yielding total selectivity of CO₂ to CO + ½O₂ with a conversion rate of 0.024 μmol·s^-1 per cm² membrane. The dynamics of the oxygen vacancy exchange, tracked by GC and XPS, further validated stable fuel production.

SUBMITTER: Tou M 

PROVIDER: S-EPMC5632959 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature