Mugheri Abdul Qayoom, Tahira Aneela, Aftab Umair, Bhatti Adeel Liaquat, Lal Ramesh, Bhatti Muhammad Ali, Memon Ghulam Zuhra, Mallah Arfana Begum, Abassi Mazhar Ali, Nafady Ayman, Ibupoto Zafar Hussain
M. A Kazi Institute of Chemistry University of Sindh Jamshoro, 76080, Sindh Pakistan.
Department of Science and Technology, Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden.
J Nanosci Nanotechnol. 2021 Apr 1;21(4):2660-2667. doi: 10.1166/jnn.2021.19108.
Cobalt oxide has been widely investigated among potential transition metal oxides for the electrochemical energy conversion, storage, and water splitting. However, they have inherently low electronic conductivity and high corrosive nature in alkaline media. Herein, we propose a promising and facile approach to improve the conductivity and charge transport of cobalt oxide Co₃O₄ through chemical coupling with well-dispersed multiwall carbon nanotubes (MWCNTs) during hydrothermal treatment. The morphology of prepared composite material consisting of nanosheets which are anchored on the MWCNTs as confirmed by scanning electron microscopy (SEM). A cubic crystalline system is exhibited by the cobalt oxide as confirmed by the X-ray diffraction study. The Co, O, and C are the only elements present in the composite material. FTIR study has indicated the successful coupling of cobalt oxide with MWCNTs. The chemically coupled cobalt oxide onto the surface of MWCNTs composite is found highly active towards oxygen evolution reaction (OER) with a low onset potential 1.44 V versus RHE, low overpotential 262 mV at 10 mAcm and small Tafel slope 81 mV dec. For continuous operation of 40 hours during durability test, no decay in activity was recorded. Electrochemical impedance study further revealed a low charge transfer resistance of 70.64 Ohms for the composite material during the electrochemical reaction and which strongly favored OER kinetics. This work provides a simple, low cost, and smartly designing electrocatalysts via hydrothermal reaction for the catalysis and energy storage applications.
在潜在的过渡金属氧化物中，氧化钴已被广泛研究用于电化学能量转换、存储和水分解。然而，它们在碱性介质中固有地具有低电子导电性和高腐蚀性。在此，我们提出一种有前景且简便的方法，通过在水热处理过程中与分散良好的多壁碳纳米管（MWCNTs）进行化学偶联，来提高氧化钴Co₃O₄的导电性和电荷传输。通过扫描电子显微镜（SEM）证实，制备的复合材料由锚定在MWCNTs上的纳米片组成。X射线衍射研究证实氧化钴呈现立方晶系。复合材料中仅存在Co、O和C元素。傅里叶变换红外光谱（FTIR）研究表明氧化钴与MWCNTs成功偶联。发现化学偶联在MWCNTs复合材料表面的氧化钴对析氧反应（OER）具有高活性，相对于可逆氢电极（RHE）的起始电位低至1.44 V，在10 mAcm时过电位低至262 mV，塔菲尔斜率小至81 mV dec⁻¹。在耐久性测试中连续运行40小时，未记录到活性衰减。电化学阻抗研究进一步表明，复合材料在电化学反应过程中的电荷转移电阻低至70.64欧姆，这强烈有利于OER动力学。这项工作通过水热反应提供了一种简单、低成本且巧妙设计的电催化剂，用于催化和能量存储应用。
