Heteroatom-doped Carbon Nanomaterials And Composites With High Electrocatalytic Activity For Oxygen Reduction And Hydrogen Evolution Reaction By Using Spark Plasma Sintering

In the face of the lack of sustainable and renewable energy sources as well as environmental pollution caused by fossil fuels, the development of alternative, clean, green and sustainable energy sources has become an urgent need. Pt-based materials are known to be the most active catalysts for oxygen reduction reaction(ORR) at the cathode in FCs.However, despite the considerable research efforts in Pt-based catalysts,large-scale commercialization is still restricted mainly by their high cost,poor durability and slow electron-transfer kinetics. In recent years, the researchers have been interested in the application of carbon nanomaterials in fuel cells, hydrogen evolution materials and supercapacitor because of their great conductivity and large specific surface area. But there is no method which could synthesize doped-carbon nanomaterials effectively and controllably because of the chemical inertness of carbon nanomaterials. Spark plasma sintering(SPS)has many greater advantages comparerd to other preparation of heteroatom-doped carbon nanomaterials such as fast heating rate, short sintering time, low sintering temperature, uniform grain size, control the structure of nanomaterials, high density, simple operation, reliable safety,good reproducibility, low cost and so on. Therefore, In this dissertation,we describe a new method of synthesis of the heteroatom-doped carbon nanomaterials with graphene as carbon source and urea, B2O3 and sulfur power as doping agent respectively. Meanwhile, we studied the oxygen reduction reaction performance of the heteroatom(nitrogen, boron,sulfur)-doped grapheneMany research have been focused on W2C as one of the most promising earth-abundant electrocatalysts for hydrogen evolution reaction.Nevertheless, the preparation of phase pure W2C represents a formidable challenge. Here we develop a method to synthesize MWCNTs/W2C composite materials by SPS. The followings are main content:(1) The heteroatom(nitrogen, boron, sulfur)-doped graphene were synthesized by using spark plasma sintering(SPS). Urea, B2O3 and sulfur power and graphene were used as doping agent and carbon source respectivley. The collected materials were characterized using the analysis method such as Raman, TEM, SEM, XRD and XPS. The electrocatalytic activities for ORR were investigated by using CV, LSV and chronoamperometry measurement in 0.1 M KOH.(2) MWCNTs/W2C composite materials were synthesized using SPS, in which MWCNTs were used as carbon source and ammonium paratungstat were used as W source. The morphology and structure were charactered by SEM, TEM, and XRD. The electrocatalytic activities for HER were investigated using LSV and chronoamperometry measurement in 0.1 M H2SO4.