Photoinduced self-assembled heterostructures of surface charge-controlled metal nucleation on supports for stable and enhanced electrocatalytic hydrogen evolution reaction activity

The synergistic effect of bimetallic heterostructures holds great importance in enhancing electrochemical performance. However, a significant challenge still remains in achieving controlled reduction pathways for heterostructured nanocrystals on supports without surfactants and comprehending the influence of structure-activity relationship on electrocatalytic performance. Herein, we have successfully controlled the surface charge of each component to precisely manipulate the nucleation sites of metal nanocrystals, achieving the highly efficient self-assembly of multiple bimetallic heterostructure nanocrystals on support through photoinduced electron transfer. As a proof-of-concept, the supported Pd@Pt heterostructure nanocrystal can be directly used and required low overpotentials of only 31 mV to achieve 10 mA cm −2 catalytic current density with a small Tafel slope of 21.3 mV·dec −1 in hydrogen evolution reaction (HER), exhibiting more than twice mass activity and superior electrocatalytic stability compared to the separately grown nanocrystals. Supported by density functional theory (DFT) calculations, it is validated that the supported bimetallic heterostructure is crucial for achieving enhanced and durable HER activity. Additionally, it is possible to effectively control and transform the supported combined models and corresponding electrocatalytic indicators by adjusting the zeta potential. This knowledge serves as insights for the supported heterostructure nanocrystals design and synthesis to enhance the activity in various electrocatalytic applications.