Enhancing the catalytic performance of PdAu catalysts by W-induced strong interaction for the direct synthesis of H2O2

The addition of non-noble metals is a promising method for developing PdAu-based catalysts for the direct synthesis of H<INF>2</INF>O<INF>2</INF>. Here, we prepared W-promoted PdAu/TiO<INF>2</INF> to enhance the synthesis of H<INF>2</INF>O<INF>2</INF>. The PdAu/WO<INF>3</INF>-TiO<INF>2</INF> catalyst, with pre-loading of W followed by PdAu presented the best performance with a H<INF>2</INF>O<INF>2</INF> yield and selectivity as high as 662.6 mol<INF>H<INF>2</INF>O<INF>2</INF></INF> kg<INF>cat</INF>-1 h-1 and 85.5%, respectively, superior to the PdAu/TiO<INF>2</INF> catalyst (450.2 mol<INF>H<INF>2</INF>O<INF>2</INF></INF> kg<INF>cat</INF>-1 h-1 and 73.9%). It was found that the W-induced strong interaction with PdAu is the key to the enhanced catalytic performance, with WO<INF>3</INF> species partially encapsulating the PdAu particles, and inducing the formation of surface PdO. However, excessive addition of W would completely coat the active metal PdAu and reduce the H<INF>2</INF>O<INF>2</INF> synthesis. Furthermore, the W promoter effect was demonstrated to be carrier-dependent. This work proves the facilitation mechanism of W and provides a promising strategy for developing PdAu-based catalysts for the direct synthesis of H<INF>2</INF>O<INF>2</INF>.