Nitrogen-doped carbon nanotubes as an excellent substrate for electroless deposition of Pd nanoparticles with a high efficiency toward the hydrogen evolution reaction

A highly efficient electrocatalyst for the hydrogen evolution reaction was developed using nitrogen-doped carbon nanotubes (N-CNTs) as a substrate for the electroless deposition of Pd nanoparticles (PdNPs). The N-CNTs were prepared with ionic liquid as a precursor through a programmed temperature method. The resulting PdNP@N-CNTs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and electrochemical impedance spectroscopy (EIS). Electrochemical experiments show that the nanocomposite has high electrocatalytic activity toward hydrogen evolution with a current density of 32 mA cm−2 at an overpotential of 100 mV and a low Tafel slope (33 mV/dec) with excellent stability. The high catalytic activity and durability were considered to be due to N atoms incorporated into the carbon skeleton forming numerous active sites for the deposition of small and uniformly distributed Pd nanoparticles. This work provides a new way to prepare highly efficient electrocatalysts for hydrogen evolution.