Enhanced hydrogen evolution reaction in alkaline solution by constructing strong metal-support interaction on Pd-CeO2-x-NC hybrids

Diminishing the size of metal nanostructures can significantly improve the performance of catalysts. However, the self-aggregation of small particles is still an insurmountable obstacle, resulting in the unfavorable stability and recyclability. Herein, we designed and fabricated the Pd-CeO 2-x -NC catalyst though an accurate deposition strategy to downsize the Pd particle to sub-nanometer level and enhance its running stability. The CeO 2-x nanoclusters were firstly dispersed on the nitrogen-doped carbon nanosheets. Further, the active Pd sub-nanoclusters were accurately scattered on the surface of CeO 2-x ascribing to the strong metal-support interaction (SMSI) between Pd and CeO 2-x , which was beneficial to promote the catalytic activity. Subsequently, the high oxidation state Pd n + species were formed due to the electron transfer from Pd to CeO 2-x caused by the SMSI effect. Strikingly, the HER performance of Pd-CeO 2-x -NC was surprisingly correlated with the ratio of Pd n + , suggesting Pd n + acted as the dominant active species. Besides, the SMSI effect stabilized the valence state of active Pd n + species and prevented the sub-nanometer Pd clusters from aggregation, which played a vital role for the enhanced stability of the hybrid catalyst. This synthetic process described here is contributed to prepare various nanostructured catalysts with satisfactory stability through the direct targeting strategy.