Abstract

It is shown that the use of aqueous electrolytes based on salts of various aromatic carboxylic acids in the course of electrochemical exfoliation of graphite allows producing multilayered graphene (MLG) and protects it from the negative oxidative action of oxygen-containing radicals, in particular, ^∙OH radicals formed at water electrolysis on the graphite anode. It is shown that the electrochemically synthesized MLG can be used for the formation of noble-metal-free carbonized nanocomposite Co–N–C electrocatalysts of the oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER). Such poly-2,6-diaminopyridine-based catalysts in aqueous 0.5 М H₂SO₄ are shown to surpass their acetylene black-based analogues as regards their functional characteristics in ORR and HER and also are highly tolerant with respect to CO and methanol in the course of oxygen reduction. Based on experimental data, it is concluded that the predominant active centers in Co–N–C electrocatalysts based on MLG and acetylene black are of the different nature and that the same active centers are involved in ORR and HER.

中文翻译：

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多层石墨烯的电化学合成及其在Co-N–C电催化剂中的氧还原和氢释放

摘要

结果表明，在石墨的电化学剥落过程中使用基于各种芳香族羧酸盐的水性电解质可以生产多层石墨烯（MLG）并保护其免受含氧自由基的负氧化作用，特别是^∙ OH自由基在水电解时在石墨阳极上形成。结果表明，电化学合成的MLG可用于氧还原反应（ORR）和氢释放反应（HER）的无贵金属碳化纳米复合Co-N-C电催化剂的形成。这种在0.5МH ₂ SO ₄水溶液中的聚2,6-二氨基吡啶基催化剂在ORR和HER中的功能特性方面，它们被证明超过了基于乙炔黑的类似物，并且在氧气还原过程中对CO和甲醇具有很高的耐受性。根据实验数据，可以得出结论，基于MLG和乙炔黑的Co-N-C电催化剂中主要的活性中心具有不同的性质，并且ORR和HER涉及相同的活性中心。