王 为,杨东子
AuthorsHTML:王 为，杨东子
AuthorsListE:Wang Wei,Yang Dongzi
AuthorsHTMLE:Wang Wei，Yang Dongzi
Unit:天津大学化工学院，天津 300350
Unit_EngLish:School of Chemical Engineering and Technology，Tianjin University，Tianjin 300350，China
Abstract_Chinese:金属、氮共掺杂碳材料类催化剂(Metal-N-C，Metal＝Fe、Mn、Co 等)具有良好的氧还原(ORR)催化性 能，成为近年应用于燃料电池正极的非铂类催化剂的研究热点．普遍上，Fe-N-C 类催化剂具有最高的 ORR 催化性 能，但其促进的 Fenton 反应(Fe2＋＋H2O2，ORR 双电子过程的副产物)会导致 PEMFC 结构损坏．因此，使用酞菁锰 (MnPc)为前驱体，通过有机金属气相沉积工艺，合成了一种以单层石墨烯为基体的 Mn-N-C 类催化剂(Mn-N-C/G- 30)．通过热重分析可知，MnPc 分子在 480 ℃下脱 H 形成悬空键而产生的分子间键合作用使其生长为 Mn-N-C/G-30 催化剂．通过 SEM、TEM、XRD 的形貌表征，表明合成 Mn-N-C/G-30 催化剂结构与前驱体酞菁锰完全不同，是一 种新型叶片状纳米材料，且具单晶结构，其晶格间距为 0.315 nm．通过 Raman 和 XPS 的结构表征，证明合成 Mn\u0002N-C/G-30 催化剂结构中形成了不同于 MnPc 中 Mn-N4 配位结构的 Mn-N 活性位点．采用了三电极体系进行电化学 测试．线性伏安扫描测试结果表明，合成 Mn-N-C/G-30 催化剂在 25 ℃、0.1 mol/L 的 KOH 水溶液中的 ORR 起始电 位和在电位 0.88 V 条件下的电流密度分别为 0.97 V 和 1.4 mA/cm2 ，优于 MnPc(0.85 V 和 0.1 mA/cm2)和商业化 Pt/C 催化剂(0.94 V 和 1.3 mA/cm2)的性能(以上电位均相对于氢标电位)．K-L 图的计算结果表明，合成 Mn-N-C/G-30 催 化剂上的 ORR 过程为高效的四电子转移步骤
Abstract_English:The oxygen reduction reaction(ORR)is an important reaction in life processes such as biological respiration and in energy conversion systems such as fuel cells. In proton-exchange membrane(PEM)fuel cells，including direct methanol fuel cells(DMFCs)，ORR is the reaction that occurs at the cathode. Electrocatalysts are used in ORR，which are a specific form of catalysts that function at electrode surfaces or may be the electrode surface itself. Metal and nitrogen co-doped carbon materials catalysts(e.g.，Metal-N-C，Metal＝Fe，Mn，and Co)have good electrocatalytic activity for ORR and has become a research hotspot for using platinum-free catalysts for the cathode of fuel cells. Generally，the Fe-N-C catalyst has the highest ORR catalytic performance，but it promotes Fenton reac\u0002tion(Fe2＋＋H2O2，the by-product of two-electron ORR processes)resulting in structural damage of proton-exchange membrane fuel cells(PEMFC). Therefore，the Mn-N-C catalyst supported by monolayer graphene(Mn-N-C/G- 30)was synthesized by metal-organic chemical vapor deposition process using manganese phthalocyanine as the precursor. Thermogravimetric analysis showed that through intermolecular bonding interaction occurring due to dehydrogenation at 480 ℃，MnPc molecules were eventually transformed into Mn-N-C/G-30 catalyst. The results of morphology characterizations by SEM，TEM，and XRD showed that the synthesized Mn-N-C/G-30 catalyst was a leaf\u0002like nanomaterial with monocrystalline structures，which is completely different from the precursor manganese phthalocyanine and its lattice spacing of 0.315 nm. The results of structure characterizations by Raman and XPS proved that novel Mn-N active sites，which are different from the Mn-N4 coordination of MnPc，were well-distributed in the Mn-N-C/G-30 catalyst. A three-electrode system was used for the electrochemical test. Linear sweep voltammetry results showed that under 25 ℃ and 0.1 mol/L KOH，the onset potential and the current density at 0.88 V of the Mn-N-C/G-30 catalyst were 0.97 V and 1.4 mA/cm2，respectively，better than that of MnPc(0.85 V and 0.1 mA/cm2)and commercial Pt/C(0.94 V and 1.3 mA/cm2). And all the mentioned above voltage is relative to hydrogen electrode. The calculation results of the K-L plot showed that ORR took place as a four-electron process on the surface of Mn-N-C/-G-30 catalyst.
Keyword_Chinese:氧还原催化剂；锰、氮共掺杂；有机金属气相沉积；酞菁锰
Keywords_English:catalyst for oxygen reduction reaction；manganese and nitrogen co-doping；metal-organic chemical vapor deposition；manganese phthalocyanine

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