Improving Catalytic Activity towards the Direct Synthesis of H<sub>2</sub>O<sub>2</sub> through Cu Incorporation into AuPd Catalysts

oleh: Alexandra Barnes, Richard J. Lewis, David J. Morgan, Thomas E. Davies, Graham J. Hutchings

Format: Article
Diterbitkan: MDPI AG 2022-11-01

Deskripsi

With a focus on catalysts prepared by an excess-chloride wet impregnation procedure and supported on the zeolite ZSM-5(30), the introduction of low concentrations of tertiary base metals, in particular Cu, into supported AuPd nanoparticles can be observed to enhance catalytic activity towards the direct synthesis of H<sub>2</sub>O<sub>2</sub>. Indeed the optimal catalyst formulation (1%AuPd<sub>(0.975)</sub>Cu<sub>(0.025)</sub>/ZSM-5) is able to achieve rates of H<sub>2</sub>O<sub>2</sub> synthesis (115 mol<sub>H<sub>2</sub>O<sub>2</sub></sub>kg<sub>cat</sub><sup>−1</sup>h<sup>−1</sup>) approximately 1.7 times that of the bi-metallic analogue (69 mol<sub>H<sub>2</sub>O<sub>2</sub></sub>kg<sub>cat</sub><sup>−1</sup>h<sup>−1</sup>) and rival that previously reported over comparable materials which use Pt as a dopant. Notably, the introduction of Cu at higher loadings results in an inhibition of performance. Detailed analysis by CO-DRFITS and XPS reveals that the improved performance observed over the optimal catalyst can be attributed to the electronic modification of the Pd species and the formation of domains of a mixed Pd<sup>2+</sup>/Pd<sup>0</sup> oxidation state as well as structural changed within the nanoalloy.