Chandrasekaran Sundaram, Hu Rong, Yao Lei, Sui Lijun, Liu Yongping, Abdelkader Amor, Li Yongliang, Ren Xiangzhong, Deng Libo
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, People's Republic of China.
College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, People's Republic of China.
Nanomicro Lett. 2023 Feb 11;15(1):48. doi: 10.1007/s40820-023-01022-8.
Rechargeable zinc-air batteries (ZABs) are a promising energy conversion device, which rely critically on electrocatalysts to accelerate their rate-determining reactions such as oxygen reduction (ORR) and oxygen evolution reactions (OER). Herein, we fabricate a range of bifunctional M-N-C (metal-nitrogen-carbon) catalysts containing M-N coordination sites and M/MC nanoparticles (M = Co, Fe, and Cu) using a new class of γ-cyclodextrin (CD) based metal-organic framework as the precursor. With the two types of active sites interacting with each other in the catalysts, the obtained Fe@C-FeNC and Co@C-CoNC display superior alkaline ORR activity in terms of low half-wave (E) potential (~ 0.917 and 0.906 V, respectively), which are higher than Cu@C-CuNC (~ 0.829 V) and the commercial Pt/C (~ 0.861 V). As a bifunctional electrocatalyst, the Co@C-CoNC exhibits the best performance, showing a bifunctional ORR/OER overpotential (ΔE) of ~ 0.732 V, which is much lower than that of Fe@C-FeNC (~ 0.831 V) and Cu@C-CuNC (~ 1.411 V), as well as most of the robust bifunctional electrocatalysts reported to date. Synchrotron X-ray absorption spectroscopy and density functional theory simulations reveal that the strong electronic correlation between metallic Co nanoparticles and the atomic Co-N sites in the Co@C-CoNC catalyst can increase the d-electron density near the Fermi level and thus effectively optimize the adsorption/desorption of intermediates in ORR/OER, resulting in an enhanced bifunctional electrocatalytic performance. The Co@C-CoNC-based rechargeable ZAB exhibited a maximum power density of 162.80 mW cm at 270.30 mA cm, higher than the combination of commercial Pt/C + RuO (~ 158.90 mW cm at 265.80 mA cm) catalysts. During the galvanostatic discharge at 10 mA cm, the ZAB delivered an almost stable discharge voltage of 1.2 V for ~ 140 h, signifying the virtue of excellent bifunctional ORR/OER electrocatalytic activity.
可充电锌空气电池（ZABs）是一种很有前景的能量转换装置，它严重依赖电催化剂来加速其速率决定反应，如氧还原（ORR）和析氧反应（OER）。在此，我们使用一类新型的基于γ-环糊精（CD）的金属有机框架作为前驱体，制备了一系列含有M-N配位位点和M/MC纳米颗粒（M = Co、Fe和Cu）的双功能M-N-C（金属-氮-碳）催化剂。由于催化剂中两种活性位点相互作用，所制备的Fe@C-FeNC和Co@C-CoNC在低半波（E）电位（分别约为0.917和0.906 V）方面表现出优异的碱性ORR活性，高于Cu@C-CuNC（约0.829 V）和商业Pt/C（约0.861 V）。作为双功能电催化剂，Co@C-CoNC表现出最佳性能，其双功能ORR/OER过电位（ΔE）约为0.732 V，远低于Fe@C-FeNC（约0.831 V）和Cu@C-CuNC（约1.411 V），以及迄今为止报道的大多数高性能双功能电催化剂。同步辐射X射线吸收光谱和密度泛函理论模拟表明，Co@C-CoNC催化剂中金属Co纳米颗粒与原子Co-N位点之间的强电子相关性可以增加费米能级附近的d电子密度，从而有效地优化ORR/OER中中间体的吸附/脱附，导致双功能电催化性能增强。基于Co@C-CoNC的可充电ZAB在270.30 mA cm时表现出162.80 mW cm的最大功率密度，高于商业Pt/C + RuO组合（在265.80 mA cm时约为158.90 mW cm）催化剂。在10 mA cm的恒电流放电过程中，ZAB在约140 h内提供了几乎稳定的1.2 V放电电压，这表明其具有优异的双功能ORR/OER电催化活性。
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