Heteroatoms doped carbon decorated with tiny amount Pt nanoparticles as a bifunctional catalyst for hydrogen and chlorine generation from seawater

N and P doped carbon nanoparticles decorated with tiny amounts of Pt nanoparticles (-6.0 wt%) were synthesized and investigated for the catalytic performances to hydrogen and chlorine generation from fresh and sea water. First, the synthesized aminophenol resin spheres were pyrolyzed, followed by microwave irradiation with a Pt compound and additional phosphorization. The SEM image of Pt decorated NPC (Pt/NPC) reveals - 200 nm nanoparticles of carbon decorated with -10.9 nm of Pt particles. Voltammograms for hydrogen production with the catalyst exhibited overpotentials of 33 mV in acidic and 25 mV in alkaline media at a current density of 10 mA/cm2. In the case of chlorine production, the catalyst displayed comparable activity to commercial Pt/C with a high selectivity of 99% at 100 mV overpotential. In seawater electrolysis, the catalyst presented low hydrogen and chlorine evolution overpotentials of 116 mV and 190 mV respectively, at a current density of 50 mA/cm2. The synergy between heteroatoms doped carbon and highly crystalized Pt nanoparticles by phosphorization provides extra active sites and causes the downshift of the d-band center of Pt particles by the interaction to negatively charged P doped carbon. Based on the DFT calculation, the electronic state of doped carbon modulated by electronegativity variations between C and N, P dopants, resulted in a reduced bandgap, which can facilitate charge transfer for the catalytic reaction. This different kinds of heteroatom doping strategy is one way to design the decoration of low content metal particles for enhanced catalytic activity of carbon materials.

Automated summary

N and P doped carbon nanoparticles decorated with tiny amounts of Pt nanoparticles were synthesized and investigated for their catalytic performances in hydrogen and chlorine generation from both fresh and sea water. The synergistic effect between heteroatoms doped carbon and highly crystallized Pt nanoparticles by phosphorization provides extra active sites, leading to enhanced catalytic activity. This different kind of heteroatom doping strategy can be a promising approach for designing low content metal particles decoration on carbon materials for improved catalytic activity.