Preparation And Properties Of Co - Doped Carbon Nanometer Oxygen Reduction Catalyst

In this thesis, nitrogen, germanium and phosphorus, germanium co-doped carbon materials(carbon nanotubes and graphene) were prepared by a two-step calcined process, which were used for the fuel cell cathode catalyst for the oxygen reduction reaction(ORR). The electrocatalytic performance and structure of the prepared carbon materials were tested and characterized by electrochemical measurement, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The prepared co-doped carbon materials show excellent ORR catalytic properties, such as high current density, positive onset potential, more tolerant to fuel crossover and long-term durability. The ORR catalytic synergistic effect has also been verified by calculating the work function based on density functional theory(DFT). Section Ⅰ:Nitrogen, germanium co-doped carbon nanotubes and graphene The germanium-doped carbon materials(Ge-CNTs and Ge-graphene) were firstly prepared by carbonizing the mixture of carboxyethyl germanium sesquioxide and carbon materials at 600 °C with the atmosphere of N2. And then the prepared solid mixtures were also heated at 600 °C in NH3 atmosphere, which obtained the nitrogen, germanium co-doped carbon materials(N-Ge-CNTs and N-Ge-graphene). In this paper, N-Ge-CNTs and N-Ge-graphene with different Ge content were also prepared, and we found that nitrogen, germanium co-doped carbon materials(N-Ge-CNTs-2 and N-Ge-graphene-2), which contain the 2 wt% carboxyethyl germanium sesquioxide addition, possess the outstanding ORR performance. Section Ⅱ:Phosphorus, germanium co-doped carbon nanotubes and grapheneThe phosphorus, germanium co-doped carbon materials(Ge-P-CNTs and Ge-P-graphene) were prepared by calcineing the germanium-doped carbon materials(Ge-CNTs and Ge-graphene) with quantitative triphenylphosphine at 600 °C in the atmosphere of N2. Similarly, Ge-P-CNTs and Ge-P-graphene with different Ge content were prepared, and we also found that phosphorus, germanium co-doped carbon materials(Ge-P-CNTs-2 and Ge-P-graphene-2), which contain the 2 wt% carboxyethyl germanium sesquioxide addition, possess the excellent ORR performance.In summary, nitrogen, phosphorus or germanium, germanium co-doping can effectively improve ORR catalytic activity of carbon nanomaterials. The ORR catalytic synergistic effect has also been verified by calculating the work function based on density functional theory(DFT).