Operando XAS study of hydrogen reaction mechanisms in novel core-shell electrocatalysts

As a continuation of the work on verifying operando XAS fuel cell utilizing Pd@CeOx catalysts, we propose an operando XAS measurement of another core-shell Pd@TiOx material on Vulcan carbon as a hydrogen oxidation reaction (HOR) catalyst in fuel cells. Compared to bare Pd nanoparticles, the Pd@TiOx catalysts exhibit superior HOR performance in alkaline media. Further investigations indicate that the introduction of a TiOx shell onto Pd nanoparticles leads to a higher CO stripping area, indicating that TiOx shell promotes CO adsorbing and oxidation. Interestingly, this phenomenon does not occur on the Pd@CeOx catalysts where, contrary, a blocking effect is observed. These observations suggest that the Pd@TiOx catalysts may have different reaction mechanism compared to Pd@CeOx. To illustrate the reaction mechanism on Pd@TiOx, we will use Pd K- and Ti K-edges XANES and EXAFS at ID26 or ID24-DCM, in an electrochemical flow cell.