MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, The Key Lab of Low-Carbon Chem and Energy Conservation of Guangdong Province, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-Sen University, 135 Xingang West Road, Guangzhou, 510275, China.
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, China.
Adv Mater. 2018 Nov;30(45):e1805268. doi: 10.1002/adma.201805268. Epub 2018 Sep 27.
Carbon composites with embedded metal/metal oxides represent a group of versatile electrochemical catalysts that has attracted extensive research attention. However, the beauty of this concept is marred by the severe carbon evaporation and the aggregation of metal species during their synthetic process, leading to the diminishment in active sites and catalytic durability. To address this issue, this study demonstrates the feasibility of utilizing Al O nanolayer to trap volatile carbon and nitrogen species and alleviate the aggregation of Co species during the pyrolysis of the Zn/Co-ZIFs (ZIF = zeolitic imidazolate framework). With the confinement effect of an Al O nanolayer, the derived Co O -embedded N-doped porous carbon grown on carbon cloth presents outstanding bifunctional catalytic activity with a small potential difference of 787 mV between the half-wave potential of the oxygen reduction reaction and an overpotential at 10 mA cm of the oxygen evolution reaction. More impressively, an advanced flexible rechargeable zinc-air battery in all-solid-state configuration is assembled, which achieves the maximum power density of 72.4 mW cm and good cycling stability. The insights produced in this work will provide guidance for the rational design of metal/carbon hybrid catalysts and low-cost renewable energy systems.
具有嵌入式金属/金属氧化物的碳复合材料代表了一类多功能电化学催化剂，引起了广泛的研究关注。然而，这个概念的美妙之处却被其在合成过程中严重的碳蒸发和金属物种聚集所破坏，导致活性位点和催化耐久性的降低。为了解决这个问题，本研究展示了利用 Al O 纳米层来捕获挥发性碳和氮物种以及缓解 Zn/Co-ZIFs（ZIF = 沸石咪唑酯骨架）热解过程中 Co 物种聚集的可行性。在 Al O 纳米层的限制作用下，衍生的 Co O 嵌入 N 掺杂多孔碳在碳布上生长，表现出出色的双功能催化活性，氧还原反应的半波电位和析氧反应 10 mA cm 过电位之间的电位差仅为 787 mV。更令人印象深刻的是，组装了具有全固态构型的先进柔性可充电锌空气电池，其最大功率密度达到 72.4 mW cm，并且具有良好的循环稳定性。本工作提供的见解将为金属/碳混合催化剂和低成本可再生能源系统的合理设计提供指导。
