In this intriguing study, our central focus revolves around efficiency of the Oxygen Evolution Reaction (OER) and methanol oxidation Reaction (MOR) through a captivating approach: harnessing the power of cobalt valence modulation in Cobaltite (CoO), achieved by the enchanting substitution of chromium (Cr). By seamlessly integrating chromium atoms into the crystal lattice of CoO, our ultimate aim is to orchestrate a remarkable transformation in the potential-determining step of the OER, resulting in a symphony of improved catalytic performance. This substitution is done by utilizing simple sol-gel method at low temperatures. This gentle adjustment of cation valence states creates oxygen vacancies on the spinel surface, achieving an ideal ion ratio of Co/Co. The formation of spinel oxides has been confirmed by a comprehensive range of precise physicochemical techniques including, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HRTEM), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET) technique and Raman spectroscopy. The presence of oxygen vacancy has been verified with Electron Paramagnetic Resonance (EPR) spectroscopy. The spinel oxide, CrCoO displays superior activity for OER with current density of 100 mA/cm at the overpotential of only 413 mV. Our findings highlight the significance of cobalt valence control in promoting OER/MOR activity, paving the way for advanced electrocatalytic systems with enhanced energy conversion capabilities.

中文翻译：

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通过铬取代微调 Co3O4 晶格中的钴价：调节析氧和甲醇氧化反应的电荷转移和氧空位


在这项有趣的研究中，我们的中心重点是通过一种迷人的方法来提高析氧反应 (OER) 和甲醇氧化反应 (MOR) 的效率：利用钴矿 (CoO) 中钴价调节的力量，通过迷人的替代来实现铬（Cr）。通过将铬原子无缝集成到 CoO 晶格中，我们的最终目标是在 OER 的潜力决定步骤中精心策划显着的转变，从而提高催化性能。这种取代是通过在低温下利用简单的溶胶-凝胶方法来完成的。这种对阳离子价态的温和调整会在尖晶石表面产生氧空位，从而实现理想的 Co/Co 离子比。尖晶石氧化物的形成已通过一系列精密物理化学技术得到证实，包括傅里叶变换红外光谱 (FTIR)、X 射线衍射分析 (XRD)、X 射线光电子能谱 (XPS)、高分辨率透射电子显微镜(HRTEM)、扫描电子显微镜 (SEM) 结合能量色散 X 射线光谱 (EDS)、Brunauer-Emmett-Teller (BET) 技术和拉曼光谱。氧空位的存在已通过电子顺磁共振（EPR）光谱得到证实。尖晶石氧化物 CrCoO 显示出优异的 OER 活性，电流密度为 100 mA/cm，过电势仅为 413 mV。我们的研究结果强调了钴价控制在促进 OER/MOR 活性方面​​的重要性，为具有增强能量转换能力的先进电催化系统铺平了道路。