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-CeO2-x-NC catalyst though an accurate deposition strategy to downsize the Pd particle to sub-nanometer level and enhance its running stability. The CeO2, nanoclusters were firstly dispersed on the nitrogen-doped carbon nanosheets. Further, the active Pd sub-nanoclusters were accurately scattered on the surface of CeO2, ascribing to the strong metal-support interaction (SMSI) between Pd and CeO2-x, which was beneficial to promote the catalytic activity. Subsequently, the high oxidation state Pdn+ species were formed due to the electron trans-fer from Pd to CeO2, caused by the SMSI effect. Strikingly, the HER performance of CeO2-x-NC was surprisingly correlated with the ratio of Pdn+, suggesting Pdn+ acted as the dominant active species. Besides, the SMSI effect stabilized the valence state of active Pdn+ species and prevented the subnanometer 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. (C) 2021 Elsevier Inc. All rights reserved.