Manipulation of Electron Transfer between Pd and TiO2 for Improved Electrocatalytic Hydrogen Evolution Reaction Performance.

The urgent need of catalysts with improved performances toward the hydrogen evolution reaction (HER) is still one of the crucial issues for the water splitting electrocatalysis. Herein, we exhibit that the HER activity of the Pd nanocubes could be improved by selecting the appropriately shaped titania nanocrystals as support. In particular, we used Pd nanoparticles with (100)-facet exposed to show that the HER performance of Pd cubes can be improved in both acidic and alkaline electrolyte media when combined on the anatase TiO2 nanocrystals. Furthermore, we have also investigated the facet effect of TiO2 on the performance in detail, which indicated stronger catalytic activity when (001)-TiO2 was used rather than (mix 101/001)-TiO2 and (101)-TiO2. The electron-transfer-induced improvement of HER activity of Pd/TiO2 was assessed by electron energy loss spectroscopy (EELS). Thereafter, the combined support materials with suitable facet exposed can give an additional adjusting path to regulate the HER activities of Pd nanocatalysts, which henceforth can further contribute to a novel way for tuning other catalysts with good electrocatalytic properties.