Enhanced hydrogen evolution reaction in alkaline solution by constructing strong metal-support interaction on Pd-CeO-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-NC catalyst though an accurate deposition strategy to downsize the Pd particle to sub-nanometer level and enhance its running stability. The CeO nanoclusters were firstly dispersed on the nitrogen-doped carbon nanosheets. Further, the active Pd sub-nanoclusters were accurately scattered on the surface of CeO ascribing to the strong metal-support interaction (SMSI) between Pd and CeO, which was beneficial to promote the catalytic activity. Subsequently, the high oxidation state Pd species were formed due to the electron transfer from Pd to CeO caused by the SMSI effect. Strikingly, the HER performance of Pd-CeO-NC was surprisingly correlated with the ratio of Pd, suggesting Pd acted as the dominant active species. Besides, the SMSI effect stabilized the valence state of active Pd 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.