Modak Arindam, Phutela Ankita, Kundu Aniruddha, Das Srijib, Bhasin Vidha, Bhattacharyya Dibyendu, Bhattacharya Saswata
Amity Institute of Applied Science (AIAS), Amity University, Noida, Uttar Pradesh 201313, India.
Department of Physics, Indian Institute of Technology Delhi (IITD), Delhi 110016, India.
J Phys Chem Lett. 2025 Jan 30;16(4):1051-1065. doi: 10.1021/acs.jpclett.4c03361. Epub 2025 Jan 22.
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are considered to be the most important processes in metal-air batteries and regenerative fuel cell devices. Metal-organic polymers are attracting interest as promising precursors of advanced metal/carbon electrocatalysts because of their hierarchical porous structure along with the integrated metal-carbon framework. We developed carbon-coated CNTs with Ni/Fe and Cu/Fe as active sites. Experimental observations from X-ray photoelectron spectroscopy and X-ray absorption analysis suggest that C@CNT[Ni] outperforms C@CNT[Cu] in the ORR and OER, which is further supported by density functional theory calculations. C@CNT[Ni] exhibits a higher onset potential (0.99 V vs RHE) and a smaller Tafel slope (40.2 mV decade) compared to those of C@CNT/[Cu] in an alkaline electrolyte (0.94 V vs RHE and 46.5 mV decade, respectively). Such circumstances are attributed to the alloying effect between Ni and Fe in C@CNT[Ni], in contrast to the existing copper iron oxide phase in C@CNT/[Cu]. It is noteworthy that C@CNT[Ni] also displayed an improved OER, demanding its bifunctional property. As a proof of concept, C@CNT[Ni] was utilized in zinc-air batteries, which shows a high energy efficiency of ∼60%, a small charge-discharge voltage gap of 0.78 V, and excellent cycling performance (∼120 h) at 5 mA cm and 25 °C. This protocol expands the utility of novel metal-organic hyper-cross-linked polymer-derived bimetallic electrocatalysts for clean energy research.
氧还原反应（ORR）和析氧反应（OER）被认为是金属空气电池和再生燃料电池装置中最重要的过程。金属有机聚合物因其具有分级多孔结构以及集成的金属 - 碳框架，作为先进金属/碳电催化剂的有前景的前体而受到关注。我们开发了以Ni/Fe和Cu/Fe作为活性位点的碳包覆碳纳米管。X射线光电子能谱和X射线吸收分析的实验观察表明，在ORR和OER中，C@CNT[Ni]的性能优于C@CNT[Cu]，密度泛函理论计算进一步支持了这一点。在碱性电解质中，与C@CNT/[Cu]相比（分别为0.94 V vs RHE和46.5 mV/decade），C@CNT[Ni]表现出更高的起始电位（0.99 V vs RHE）和更小的塔菲尔斜率（40.2 mV/decade）。这种情况归因于C@CNT[Ni]中Ni和Fe之间的合金化效应，而C@CNT/[Cu]中存在铜铁氧化物相。值得注意的是，C@CNT[Ni]的OER也有所改善，这要求其具有双功能特性。作为概念验证，C@CNT[Ni]被用于锌空气电池中，该电池在5 mA/cm²和25°C下显示出约60%的高能量效率、0.78 V的小充放电电压差以及出色的循环性能（约120小时）。该方案扩展了新型金属有机超交联聚合物衍生的双金属电催化剂在清洁能源研究中的应用。
