催化作用
阳极
化学工程
阴极
材料科学
成核
电池(电)
碳纳米管
电化学
双功能
电子转移
无机化学
化学
纳米技术
电极
光化学
有机化学
物理化学
工程类
功率(物理)
物理
量子力学
作者
Jiaqi Niu,Chaoyao Geng,Xiaoqiang Liu,Anthony P. O’Mullane
标识
DOI:10.1016/j.cej.2023.143607
摘要
To improve the kinetics of the ORR/OER at the cathode and inhibit dendrite formation on the anode of a Zn-Air battery (ZAB), a new polyoxometalate (POM) with a basic structrual unit of [Zn{P4Mo6}2] was designed and converted to well-separated Zn/Mo2C catalytic sites on Co, N doped carbon nanotubes (Co-NCNTs) derived from ZIF-67. This conversion was achieved at a relatively low pyrolysis temperature of 600 °C, which circumvented the collapse of catalyst structures, burial of catalytic sites and volatilization of metals. The experimental results demonstrate that the pyrolysis of [Zn{P4Mo6}2] can etch Co-NCNTs-800 to produce a porous structure with an enlarged specific surface area, thus increasing the number of catalytic sites and promoting the transfer of electrons/ions. The high-valence Mo atoms from the POM precursor are inclined to hybridize with O active intermediates produced during ORR/OER, which can improve electron exchange and the ORR/OER performance. Furthermore, the multi-catalytic sites (Zn and Mo2C, etc.) produced from the [Zn{P4Mo6}2] precursor can not only facilitate ORR/OER at the battery cathode, but also inhibit the formation of zinc dendrites by forming a large number of nucleation sites on the battery anode. Accordingly, the ZABs assembled with the POM-derived catalyst exhibit a high open circuit voltage of 1.506 V and a peak power density of 223.54 mW cm−2. Moreover, the assembled all-solid coin cell ZABs also display high capacity and long-term charge–discharge stability. Furthermore, density functional theory calculations demonstrate that the synergy between Zn/Mo2C and Co-NCNTs active sites mainly contributes to the superior ORR/OER catalytic performance.
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