Yan Jianhua, Wang Ying, Zhang Yuanyuan, Xia Shuhui, Yu Jianyong, Ding Bin
Key Laboratory of Textile Science & Technology, College of Textile, Donghua University, Shanghai, 201620, China.
Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China.
Adv Mater. 2021 Feb;33(5):e2007525. doi: 10.1002/adma.202007525. Epub 2020 Dec 18.
Designing stable and efficient electrocatalysts for both oxygen reduction and evolution reactions (ORR/OER) at low-cost is challenging. Here, a carbon-based bifunctional catalyst of magnetic catalytic nanocages that can direct enhance the oxygen catalytic activity by simply applying a moderate (350 mT) magnetic field is reported. The catalysts, with high porosity of 90% and conductivity of 905 S m , are created by in situ doping metallic cobalt nanodots (≈10 nm) into macroporous carbon nanofibers with a facile electrospinning method. An external magnetic field makes the cobalt magnetized into nanomagnets with high spin polarization, which promote the adsorption of oxygen-intermediates and electron transfer, significantly improving the catalytic efficiency. Impressively, the half wave-potential is increased by 20 mV for ORR, and the overpotential at 10 mA cm is decreased by 15 mV for OER. Compared with the commercial Pt/C+IrO catalysts, the magnetic catalyzed Zn-air batteries deliver 2.5-fold of capacities and exhibit much longer durability over 155 h. The findings point out a very promising strategy of using electromagnetic induction to boost oxygen catalytic activity.
设计低成本、用于氧还原反应和析氧反应（ORR/OER）的稳定高效电催化剂具有挑战性。在此，报道了一种磁性催化纳米笼碳基双功能催化剂，通过简单施加适度（350 mT）的磁场可直接增强氧催化活性。这些催化剂通过简便的电纺丝方法将金属钴纳米点（≈10 nm）原位掺杂到大孔碳纳米纤维中制备而成，孔隙率高达90%，电导率为905 S m 。外部磁场使钴磁化成为具有高自旋极化的纳米磁体，促进氧中间体的吸附和电子转移，显著提高催化效率。令人印象深刻的是，ORR的半波电位提高了20 mV，OER在10 mA cm 时的过电位降低了15 mV。与商业Pt/C+IrO催化剂相比，磁催化锌空气电池的容量提高了2.5倍，并且在超过155小时的时间内表现出更长的耐久性。这些发现指出了一种利用电磁感应提高氧催化活性的非常有前景的策略。
