生物质不同部位制备炭基催化剂及其电催化氧还原性能

Preparation and investigation of carbon-based electrocatalysts from different parts of biomass for oxygen reduction reaction

  • 摘要: 炭基氧还原催化剂因其具有成本低、导电性能好,结构可调控、电化学稳定性好等特点在电催化氧还原领域应用广泛。本研究以不同结构(叶、茎)的生物质(苋菜)为原料,通过一步热解法制备炭材料,结合X射线衍射仪、拉曼光谱、X射线光电子能谱以及线性扫描伏安法等物理化学特性分析所制备材料的电催化氧还原反应性能。结果表明,相对于茎源炭,叶源炭(比表面积为732.31 m2/g)的杂原子掺杂更为丰富,特别是其较高的P、S和N共掺杂,尤其是石墨氮和吡啶氮的总含量明显提升。这也使得其在较宽的pH区间(酸性、中性、碱性溶液)表现出优异的氧还原活性(起始还原电位:0.529、0.215、−0.046 V(vs. SCE))。这表明生物质原料自身特性对热解后炭材料的组成、形貌和结构有较大影响,叶源生物炭因其具有更为丰富的杂原子掺杂使得其在催化燃料电池氧还原领域具有广阔的应用前景。

     

    Abstract: Carbon-based oxygen reduction catalysts are widely used in catalyzing the oxygen reduction reaction (ORR) due to their low cost, good electrical conductivity, controllable pore structure and good electrochemical stability. In this paper, carbon materials were prepared from different parts of biomass (leaves and stems) through one-step pyrolysis method. The performance of the obtained catalysts was analyzed by X-ray diffraction (XRD), Raman, X-ray Photoelectron Spectroscopy (XPS) and Linear Sweep Voltammetry (LSV). The results demonstrate that compared with the stem carbon, the leaf carbon contains high contents of P, S and N, especially quaternary-N and pyridinic-N, which are responsible for the high performance in the ORR with onset potentials of 0.529, 0.215 and −0.046 V (vs. SCE) in wide ranges of pH (acid, alkali and neutral solutions, respectively). This indicates that biomass based carbon material especially leaf based shows a great application potential for catalyzing ORR in fuel cells.

     

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