Electrocatalytic activity of a new, pristine and graphene-modified NiCo₂O₄–NiO catalysts towards oxygen reduction reaction (ORR) was gauged. Linear sweep voltammetry attests that NiCo₂O₄–NiO (NCO) catalyst, obtained by a facile synthesis route based on a self-assembling co-templated by diethanolamine (DEA) and tripropylamine (TPA), shows conspicuous catalytic activity towards ORR. The catalytic activity of NCO was tentatively ascribed to the presence of the cubic spinel NiCo₂O₄ and of a small amount of NiO, as a secondary phase (evidenced by XPS and XRD) which most likely enables the formation of efficient active sites and enhances the conductivity of the material. After mixing the NCO with reduced graphene oxide (rGO), the catalytic activity of the new composite NiCo₂O₄–NiO-rGO (NCO-rGO) was significantly improved. Electrochemical results reveal that the presence of graphene facilitates a more efficient mass transport, supplies more accessible active sites, and provides higher stability and better resistance to deactivation during ORR. The synthesis route herein developed for preparing NCO material might be successfully used for large-scale applications due to its outstanding features, such as low cost, easy availability, and straightforward control of the phase composition.

Graphical Abstract

测量了一种新的，原始的和石墨烯改性的NiCo ₂ O ₄ -NiO催化剂对氧还原反应（ORR）的电催化活性。线性扫描伏安法证明，通过基于二乙醇胺（DEA）和三丙胺（TPA）共同模板化的自组装的简便合成路线获得的NiCo ₂ O ₄ -NiO（NCO）催化剂具有显着的ORR催化活性。NCO的催化活性暂时归因于立方尖晶石NiCo ₂ O _4的存在作为第二相（由XPS和XRD证明），以及少量的NiO，最有可能使形成有效的活性位点并增强材料的电导率。将NCO与还原的氧化石墨烯（rGO）混合后，新型复合NiCo ₂ O ₄的催化活性–NiO-rGO（NCO-rGO）得到了显着改善。电化学结果表明，石墨烯的存在促进了更有效的质量传输，提供了更多可及的活性位点，并在ORR过程中提供了更高的稳定性和更好的抗失活性。本文开发的用于制备NCO材料的合成路线由于其杰出的特性（例如低成本，易获得性以及相组成的直接控制）而可以成功地用于大规模应用。

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