Preparation And Electrochemical Application Of Heteroatom Doped Nanocarbons

Hydrogen as clean, secure and renewable energy carrier, can meet the growing demand for energy. Electrochemical reduction of water to hydrogen is a promising way for industrial application. Recently, metal-free doped carbon materials were massively studied due to their advantages of low cost and simple synthesis relative to commercially available precious metal catalyst. Considering the utilization of overwhelming metals in synthetic procedures, but identifying the real responsible sites of these metal-free doped carbons and the intrinsic role of the input metals remains unclear. To solve the concerns, the essay is summarized as following aspects:1, By using a one-step annealing method, nitrogen doped carbon was synthesized and further applied in hydrogen evolution reaction. Ethylenediamine-tetraacetic acid was used as a carbon source, while melamine and KOH played roles of nitrogen source and activating agent, respectively. We systematically researched the influence of pyrolysis temperature on the electrochemical activity of doped carbons. It showed that nitrogen doping can act as active site of electrocatalysis. A combination of nitrogen doping and graphitization is the key for excellent performance.2, To further improve the activity of nanocarbon materials and research the influence of the induced transitional metal on the structure of carbon material and electrochemical activity, transitional metal coordinated nitrogen doped porous carbons were synthesized and applied as electrocatalysts towards hydrogen evolution reaction. Types of nitrogen, defects density of carbon materials, morphology, content and the form of metallic residue were discussed when different kinds of transitional metal sources were induced. Among them, cobalt coordinated nitrogen doped porous nanocarbon showed the highest activity in electrolytes over the range of pH 0 to pH 14. In acid electrolyte, it exhibited superior performance towards hydrogen evolution reaction, with an onset potential of-90 mV, while tafel slope was calculated to be 122 mV dec-1.3, By adjusting the cobalt precursor, we investigated the relationship between the content of residue cobalt and catalytic activity. Remaining metallic sites were revealed to be extremely stable in acid electrolyte and act as intrinsic active sites. In this work, we studied the effect of metallic residue towards the electrochemical activity. The metal-N/Cx configurations were the main electrochemically catalytically active species.