In-situ growth of Ni nanoparticle-encapsulated N-doped carbon nanotubes on carbon nanorods for efficient hydrogen evolution electrocatalysis

Searching for inexpensive, efficient and durable electrocatalysts with earth-abundant elements toward the hydrogen evolution reaction (HER) is of vital importance for the future sustainable hydrogen economy, yet still remains a formidable challenge. Herein, a facile template-engaged strategy is demonstrated for the direct in-situ growth of Ni nanoparticles and N-doped carbon nanotubes on carbon nanorod substrates, forming a hierarchically branched architecture (abbreviated as Ni@N-C NT/NRs hereafter). The elaborate construction of such unique hierarchical structure with tightly encapsulated Ni nanoparticles and open configuration endows the as-fabricated Ni@N-C NT/NRs with abundant well-dispersed active sites, enlarged surface area, reduced resistances of charge transfer and mass diffusion, and reinforced mechanical robustness. As a consequence, the optimal Ni@N-C NT/NR catalyst demonstrates superior electrocatalytic activity with relatively low overpotential of 134 mV to deliver a current density of 10 mA·cm^-2 and excellent stability for HER in 0.1 M KOH, holding a great promise for practical scalable H₂ production. More importantly, this work offers a reliable methodology for feasible fabrication of robust high-performance carbon-based hierarchical architectures for a variety of electrochemical applications.