1 research outputs found
Origin of Active Oxygen in a Ternary CuO<sub><i>x</i></sub>/Co<sub>3</sub>O<sub>4</sub>–CeO<sub>2</sub> Catalyst for CO Oxidation
We
have studied CO oxidation over a ternary CuO<sub><i>x</i></sub>/Co<sub>3</sub>O<sub>4</sub>–CeO<sub>2</sub> catalyst
and employed the techniques of N<sub>2</sub> adsorption/desporption,
XRD, TPR, TEM, <i>in situ</i> DRIFTS, and QMS (quadrupole
mass spectrometry) to explore the origin of active oxygen. DRIFTS-QMS
results with labeled <sup>18</sup>O<sub>2</sub> indicate that the
origin of active oxygens in CuO<sub><i>x</i></sub>/Co<sub>3</sub>O<sub>4</sub>–CeO<sub>2</sub> obeys a model, called
a queue mechanism. Namely gas-phase molecular oxygens are dissociated
to atomic oxygens and then incorporated in oxygen vacancies located
at the interface of Co<sub>3</sub>O<sub>4</sub>–CeO<sub>2</sub> to form active crystalline oxygens, and these active oxygens diffuse
to the CO–Cu<sup>+</sup> sites thanks to the oxygen vacancy
concentration magnitude and react with the activated CO to form CO<sub>2</sub>. This process, obeying a queue rule, provides active oxygens
to form CO<sub>2</sub> from gas-phase O<sub>2</sub> via oxygen vacancies
and crystalline oxygen at the interface of Co<sub>3</sub>O<sub>4</sub>–CeO<sub>2</sub>