Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, School of Chemistry and Materials Science, Heilongjiang University , Harbin 150080, China.
Key Laboratory of Chemical Engineering Process and Technology for High-Efficiency Conversion, College of Heilongjiang Province, School of Chemistry and Materials Science, Heilongjiang University , Harbin 150080, China.
ACS Appl Mater Interfaces. 2016 Oct 5;8(39):25923-25932. doi: 10.1021/acsami.6b06895. Epub 2016 Sep 26.
The low electrocatalytic activity for oxygen reduction reaction (ORR) and the high cost of cathode catalyst in microbial fuel cells (MFCs) are the important factors that limit the practical applications. The metal-free nitrogen (N)-doped partly graphitized carbon (NPGC) as cathode catalyst is prepared at different temperatures (700-1050 °C) by using waste cornstalks as the carbon source and melamine as the N source. Scanning electron microscopy, X-ray diffraction, specific surface areas, and transmission electron microscopy have been used, in parallel with electrochemical activity tests including rotating disk electrode (RDE) and power output, to clarify how the active constituents and structure of NPGC influence the MFCs performance. Carbonization temperature has a significant effect on the porous structure and N-doped defects (pyridinic, pyrrolic, and graphitic N), which correspondingly influence the amount of active sites, ORR activity and long-time running durability in MFCs. The abundant functional oxygen-containing groups in the porous structure (1177.76 m g) of NPGC (1000 °C) contribute to the fast adsorption of molecular O onto the carbon skeleton. The N-induced charge delocalization facilitates the chemisorption of O and cleavage of O-O bonds to effectively enhance the four-electron O reduction on NPGC electrode. The maximum power density of NPGC-1000 is 1122 mW m in MFCs, which is higher than that of Pt/C (988 mW m), and only has a decline of 10.2% after 80 days. This work provides a metal-free, high-efficiency, and cost-effective ORR electrocatalyst for MFCs.
作为阴极催化剂的无金属氮（N）掺杂部分石墨化碳（NPGC），是在不同温度（700-1050°C）下，以废弃玉米秸秆为碳源，三聚氰胺为 N 源制备的。采用扫描电子显微镜、X 射线衍射、比表面积和透射电子显微镜，以及旋转圆盘电极（RDE）和功率输出等电化学活性测试，阐明了 NPGC 的活性成分和结构如何影响 MFCs 的性能。碳化温度对多孔结构和 N 掺杂缺陷（吡啶、吡咯和石墨 N）有显著影响，这相应地影响了活性位点的数量、ORR 活性和在 MFCs 中的长期运行耐久性。NPGC（1000°C）多孔结构中丰富的功能含氧基团（1177.76 m g）有助于分子 O 快速吸附到碳骨架上。N 诱导的电荷离域有利于 O 的化学吸附和 O-O 键的断裂，从而有效地增强了 NPGC 电极上的四电子 O 还原。在 MFCs 中，NPGC-1000 的最大功率密度为 1122 mW m，高于 Pt/C（988 mW m），并且在 80 天后仅下降了 10.2%。这项工作为 MFCs 提供了一种无金属、高效且具有成本效益的 ORR 电催化剂。
