Effective synergy between palladium nanoparticles and nitrogen-doped porous carbon fiber for hydrogen evolution reaction

Abstract

Efficient and stable electrocatalysts are essential for generating continuous and clean hydrogen energy through electrochemical water splitting. Palladium (Pd) has been widely used in various catalytic reactions due to its unique electronic structures and chemical properties. Herein, we reported a facile synthesis strategy to homogeneously embed Pd nanoparticles in nitrogen-doped porous carbon fibers (Pd-PCNFs) through three successive processes of pre-oxidation, carbonization, and etching. The porous carbon fiber not only acts as a support matrix for highly dispersed Pd nanoparticles to avoid sintering in the high temperature process, but also provides efficient ion penetration and mass transport during the hydrogen evolution reaction (HER) process. More importantly, Raman and X-ray photoelectron spectroscopy (XPS) characterization confirmed the effective synergy between Pd nanoparticles and N-doped porous carbon fibers, which will help enhance the intrinsic electrocatalytic activity of Pd nanoparticles. Consequently, Pd-PCNFs-800 obtained by annealing at 800 °C exhibit significantly enhanced and stable electrocatalytic activity with an onset potential of 0 mV (0.5 M H2SO4) and 40 mV (1 M KOH). It is noteworthy that the catalytic activity of Pd-PCNFs-800 is close to or better than commercial 10% Pd/C in different electrolytes. Impressively, in alkaline media, the activity of Pd-PCNFs-800 is even superior to commercial Pt/C at large current densities (>48.6 mA cm−2). This work provides a novel perspective to design and enrich the applications of Pd-based catalysts supported on carbon substrates.