Influence of alloying and surface overcoating engineering on the electrochemical properties of carbon-supported PtCu nanocrystals

Designing nanostructured Pt-based materials with unique properties as electrocatalyst attracts great research interests to achieve clean and sustainable energy. Herein, we investigate nanoscale engineering of carbon-supported PtCu nanocrystals (NCs) through tailoring their electronic and geometry properties by means of alloying and surface overcoating. Alloying Pt with Cu enhances the catalytic efficiencies for the acidic hydrogen evolution reaction (HER). Subsequent surface overcoating of PtCu nanostructures with carbon nanoshells endows a decreased mass activity towards the HER catalysis compared to the uncoated counterparts, this can be mainly associated with annealing-induced sintering of small metal nanoparticles and the surface site-blockage of metal active sites. These results indicate that breaking activity-stability trade-off remains to be challenging for efficient HER catalysis on carbon-supported PtCu nanostructures. Our case study on the limitations of fabricating PtCu nanodendrites with varied loadings of carbon nanoshells on the surface demonstrates the necessity to explore the design of advanced and high-performing metal-based catalysts.