Abstract
•We prepared Pd–Cu/TiO2 catalysts with different anatase/rutile phase compositions.•Pretreatment by H2 reduction generated an SMSI over the catalysts before the reaction.•The catalyst containing more anatase phase showed stronger metal-support interaction.•The performance of catalyst depended on the degree of SMSI.•We correlated the catalytic performances with the degree of SMSI using TPR and XPS.
In this study, we prepared TiO2-supported Pd–Cu catalysts of different anatase/rutile phase compositions, which were used in a nitrate reduction in water. It was shown that the catalysts containing a greater anatase phase composition had higher catalytic performance. Through characterization studies using H2-temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS), the observed trend of the catalytic activity was correlated to the degree of the strong metal-support interaction (SMSI) over the catalysts. The SMSI occurred through pre-treatment of the catalysts by H2 reduction (at 200°C), which resulted in increased partially reduced TiO2−x and electron-rich active metal (Pd and Cu) states at the catalyst of higher composition of anatase phase. The relationships between the changes in the properties and activities of the catalysts as a result of the anatase phase composition are discussed.