Superhydrophobic Air-Breathing Cathode for Efficient Hydrogen Peroxide Generation through Two-Electron Pathway Oxygen Reduction Reaction
Superhydrophobic Air-Breathing Cathode for Efficient Hydrogen Peroxide Generation through Two-Electron Pathway Oxygen Reduction Reaction
复制标题
超疏水呼吸空气阴极通过双电子途径氧还原反应高效生成过氧化氢
DOI：
10.1021/acsami.9b09942
复制
发表时间：
2019
影响因子：
9.5
通讯作者：
Li Nan
中科院分区：
文献类型：
--
作者：
Zhao Qian;An Jingkun;Wang Shu;Qiao Yujie;Liao Chengmei;Wang Cong;Wang Xin;Li Nan
碳基材料通过双电子途径的氧还原反应（ORR）的电催化为原位制备过氧化氢（H2 O2）提供了巨大的潜力。本文通过调节石墨/炭黑/聚四氟乙烯（PTFE）杂化催化剂层（CL）中PTFE的含量来调节催化剂的介观结构和亲水/疏水性，旨在提高双电子ORR活性，从而有效地产生H2 O2。PTFE 0.57作为唯一一种引发接触角为141.11°的超疏水化学发光材料，在25 mA cm-2时获得了最高的H2 O2产率（3005 ± 58 mg L-1h-1）和最高的电流效率（CE）（84%）（20 mA cm-2）。旋转环盘电极（RRDE）的结果表明，在CL中的PTFE含量越少，电子转移越少，对双电子ORR的选择性越好。PTFE含量最低的PTFE 0. 57在25 mA cm-2时H2浓度最高（2 μmol L-1），但随着PTFE含量的增加，CE呈负相关下降，说明H2 O2分解反应是主要的副反应。高PTFE含量增加了CL的亲水性，因为过量的H+和不充分的O2扩散，导致H2 O2分解成H2O。同时，CLs的电活性表面积随着PTFE含量的增加而降低，从PTFE 0.57的0.0041 m2 g-1降低到PTFE 4.56的0.0019 m2 g-1。此外，CL中PTFE含量的增加导致总阻抗增加（从PTFE 0.57的14.5 Ω增加到PTFE 4.56的18.3 Ω），进一步阻碍了电子传递和ORR活性。
Electrochemical catalysis of carbon-based material via two-electron pathway oxygen reduction reaction (ORR) offers great potential for in situ hydrogen peroxide (H2O2) production. In this work, we tuned catalyst mesostructure and hydrophilicity/hydrophobicity by adjusting polytetrafluoroethylene (PTFE) content in graphite/carbon black/PTFE hybrid catalyst layer (CL), aimed to improving the two-electron ORR activity for efficient H2O2generation. As the only superhydrophobic CL with initiating contact angles of 141.11°, PTFE0.57obtained the highest H2O2yield of 3005 ± 58 mg L–1h–1(at 25 mA cm–2) and highest current efficiency (CE) of 84% (at 20 mA cm–2). Rotating ring disk electrode (RRDE) results demonstrated that less PTFE content in CLs results in less electrons transferred and better selectivity toward two-electron ORR. Though the highest H2concentration (2 μmol L–1at 25 mA cm–2) was monitored from PTFE0.57which contained the lowest PTFE, the CE decreased inversely with increasing content of PTFE, which proved that the H2O2decomposition reaction was the major side reaction. Higher PTFE content increased the hydrophilicity of CL for excessive H+and insufficient O2diffusion, which induced H2O2decomposition into H2O. Simultaneously, the electroactive surface area of CLs decreased with higher PTFE content, from 0.0041 m2g–1of PTFE0.57to 0.0019 m2g–1of PTFE4.56. Besides, higher PTFE content in CL leads to the increase of total impedance (from 14.5 Ω of PTFE0.57to 18.3 Ω of PTFE4.56), which further hinders the electron transfer and ORR activity.