A first-principles study of reaction mechanism over carbon decorated oxygen-deficient TiO_(2) supported Pd catalyst in direct synthesis of H_(2)O_(2)

The choice of support is one of the most significant components in the direct synthesis of H_(2)O_(2).Aiming to improvement of activity and selectivity of H_(2)O_(2) on Pd/TiO_(2) surface,we systematically investigated the important elementary steps on Pd/TiO_(2)-Vo@C,Pd/TiO_(2)-Vo,Pd/TiO_(2)-2 Vo,Pd/TiO_(2),and Pd/C using the first-principles calculations.The Bader charge analysis and charge density difference of O_(2) adsorption elucidate the relationship between the electronic distribution and chemisorption energy.The effective barrier analysis further enables to quantitatively estimate the reactivity of H_(2)O_(2) and H2O.We demonstrate unambiguously that the selectivity of H2O formation is boosted as the oxygen vacancy concentration raised.Moreover,the introduction of C into a TiO_(2) with appropriate oxygen vacancies can slightly reduce the effective barrier for H_(2)O_(2) formation and increase the effective barrier for H2O formation leading to a higher activity and selectivity of H_(2)O_(2) formation.Our finding suggests that carbon-doped oxygen vacancy TiO_(2) supported Pd is potential alternative catalyst compared with the Pd/TiO_(2).