Engineering Platinum-Cobalt Nano-alloys in Porous Nitrogen-Doped Carbon Nanotubes for Highly Efficient Electrocatalytic Hydrogen Evolution

Highly efficient electrocatalysts are essential for the production of green hydrogen from water electrolysis. Herein, a metal-organic framework-assisted pyrolysis-replacement-reorganization approach is developed to obtain ultrafine PtCo alloy nanoparticles (sub-10 nm) attached on the inner and outer shells of porous nitrogen-doped carbon nanotubes (NCNT) with closed ends. During the thermal reorganization, the migration of Pt-Co nano-alloys to both surfaces ensures the maximized exposure of active sites while maintaining the robust attachment to the porous carbon matrix. Density functional theory calculations suggest a nearly thermodynamically-neutral free energy of adsorption for hydrogen intermediates and diversified active sites induced by alloying, thus resulting in a great promotion in intrinsic activity towards the hydrogen evolution reaction (HER). Benefiting from the delicate structural design and compositional modulation, the optimized Pt3Co@NCNTelectrocatalyst manifests outstanding HER activity and superior stability in both acidic and alkaline media.

Automated summary

In this study, ultrafine PtCo alloy nanoparticles attached on porous nitrogen-doped carbon nanotubes were synthesized using a metal-organic framework-assisted pyrolysis-replacement-reorganization approach. The resulting electrocatalyst exhibited outstanding activity and stability in the hydrogen evolution reaction due to the unique structure and diversified active sites induced by alloying.