Preparation And Properties Of Carbon - Based Non - Noble Oxygen Reduction Catalysts

Replacing the rare and precious platinum(Pt) electrocatalysts with low-cost and efficient the cathode oxygen reduction reaction(ORR) electrocatalysts is essential for polymer-electrolyte membrane fuel cells(PEMFCs). Engineering the non-precious catalysts materials with optimized composition and fine nanostructure, which providing new opportunities for enhancing ORR performance. This paper develops novel non-noble metal catalyst with an effective pre-assembled catalyst precursor by weak interactions(electrostatic and hydrogen bonding), then calcined at a high temperature. The prepared catalyst material exhibited excellent ORR catalytic performance. This synthetic mechanism enlighten the future design of nanostructured materials as an alternation for precious metal based catalysts for highly efficient ORR, which makes it a promising in the large-scale commercial production. This study contains the following parts:1. Nitrogen doped carbon nanotubes encapsulated cobalt nanoparticles(Co@N-CNTs) catalyst for oxygen reduction reaction. A nitrogen doped carbon nanotubes encapsulated cobalt nanoparticles(Co@N-CNTs) catalyst was prepared by assembling the precursors of melamine and cobalt nitrate hexahydrate, followed by gradient temperature carbonization in the presence of glucose as a reducing agent. The as prepared Co@N-CNTs composite exhibited superior electroactivity and long-term stability toward ORR in both alkaline and acidic solution.2. A carbon nanosheets with carbon nanoparticles and codoped with nitrogen and phosphorus catalyst for oxygen reduction reaction. We developed a simple template-free approach to nanosheets carbon with carbon nanoparticles codoped with nitrogen and phosphorus by pyrolysis of a self-assembled melamine and phytic acid. The pyrolyzed N-P/CNS-1000 exhibited excellent ORR activity in a nearly four-electron pathway with an better onset potential and limiting current density, comparable to commercial Pt/C catalyst. Furthermore, the hybrid exhibited superior methanol tolerance and long-term stability in alkaline solution. This synthetic mechanism enlighten the future design of metal-free catalysts as an alternation for metal based catalysts for highly efficient ORR.