Abdelwahab Abdalla, Carrasco-Marín Francisco, Pérez-Cadenas Agustín F
Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University, Beni-Suef 62511, Egypt.
Carbon Materials Research Group, Department of Inorganic Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva s/n, ES18071 Granada, Spain.
Materials (Basel). 2019 Jul 31;12(15):2446. doi: 10.3390/ma12152446.
A total of two carbon xerogels doped with cobalt and nickel were prepared by the sol-gel method. The obtained carbon xerogels underwent further surface modification with three binary metal oxides namely: nickel cobaltite, nickel ferrite, and cobalt ferrite through the hydrothermal method. The mesopore volumes of these materials ranged between 0.24 and 0.40 cm/g. Moreover, there was a morphology transformation for the carbon xerogels doped with nickel cobaltite, which is in the form of nano-needles after the hydrothermal process. Whereas the carbon xerogels doped with nickel ferrite and cobalt ferrite maintained the normal carbon xerogel structure after the hydrothermal process. The prepared materials were tested as electrocatalysts for oxygen reduction reaction using 0.1 M KOH. Among the prepared carbon xerogels cobalt-doped carbon xerogel had better electrocatalytic performance than the nickel-doped ones. Moreover, the carbon xerogels doped with nickel cobaltite showed excellent activity for oxygen reduction reaction due to mesoporosity development. NiCoO/Co-CX showed to be the best electrocatalyst of all the prepared electrocatalysts for oxygen reduction reaction application, exhibiting the highest electrocatalytic activity, lowest onset potential E of -0.06 V, and the lowest equivalent series resistance (ESR) of 2.74 Ω.
通过溶胶 - 凝胶法总共制备了两种掺杂钴和镍的碳干凝胶。所获得的碳干凝胶通过水热法用三种二元金属氧化物，即钴酸镍、镍铁氧体和钴铁氧体进行进一步的表面改性。这些材料的中孔体积在0.24至0.40 cm/g之间。此外，掺杂钴酸镍的碳干凝胶发生了形态转变，水热过程后呈纳米针状。而掺杂镍铁氧体和钴铁氧体的碳干凝胶在水热过程后保持正常的碳干凝胶结构。使用0.1 M KOH将制备的材料作为氧还原反应的电催化剂进行测试。在所制备的碳干凝胶中，掺杂钴的碳干凝胶比掺杂镍的具有更好的电催化性能。此外，由于中孔的发展，掺杂钴酸镍的碳干凝胶对氧还原反应表现出优异的活性。在所有制备的用于氧还原反应的电催化剂中，NiCoO/Co-CX是最好的电催化剂，表现出最高的电催化活性、最低的起始电位E为 -0.06 V以及最低的等效串联电阻（ESR）为2.74Ω。
