Strategies to enhance the electrochemical performances of Pt-based intermetallic catalysts.

The need for improving the energy conversion efficiency of proton exchange membrane fuel cells (PEMFCs) has motivated the development of advanced electrocatalysts with desirable activity and durability. Pt-Based intermetallic compounds, featuring atomically ordered structures, have long been considered to be very promising alternatives to widely employed Pt and Pt alloy (solid solutions) catalysts. To facilitate the practical application of Pt-based intermetallics in PEMFCs, effective strategies have been developed to further improve their catalytic activity and durability over the last decade. This feature article overviews the recent advances on the strategies for enhancing the electrochemical performances of Pt-based intermetallic catalysts, which include size control, surface engineering, and composition tuning. Thermodynamic and kinetic perspectives on the formation of the intermetallic phases are summarized to better design the synthesis conditions and realize the size control. After this, the size-control approaches (e.g. coating protection, matrix protection) are illustrated and discussed. We highlight the positive effect of surface engineering and discuss the recently developed methods for surface engineering. Finally, we discuss the thermodynamic feasibility of composition tuning and recent work based on composition-tunable intermetallic electrocatalysts.