Department of Chemistry, Yangzhou University, Yangzhou 225002, Jiangsu Province, PR China.
J Phys Chem B. 2012 Oct 18;116(41):12567-73. doi: 10.1021/jp3059189. Epub 2012 Oct 5.
Electrochemical oxidation of pyrogallol in a pH 5.0 phosphate buffer was carried out on a reduced graphene oxide/glassy carbon (RGO/GC) electrode. Reduced graphene oxide plays an important role in catalyzing the electrochemical oxidation of pyrogallol. A deep yellow film deposited on the electrode exhibits electroactivity in a wide pH range. On the basis of the experimental results from measurements of (1)H NMR, (13)C NMR, and IR spectra, there are hydroxyl, carbonyl, and aldehyde groups in the product. No visible absorption peak occurs in the UV-vis spectrum of the product, and its molecular weight is lower than that of the dipolymer but higher than that of the monomer. Therefore, the film is neither a polymer nor a dipolymer and is only a product of pyrogallol oxidation with oxygen radicals. No tendency toward the decay of the ESR signal intensity of the electrogenerated film deposited on the RGO/graphite electrode was observed after 210 days. Electrogenerated film was used as a radical source to test the radical scavenging abilities of ascorbic acid, catechin, and catechol in aqueous solutions based on the ESR signal intensity. The result indicates that ascorbic acid and catechin can scavenge the free radicals, but catechol can hardly scavenge the free radicals.
在 pH 5.0 的磷酸盐缓冲液中，通过在还原氧化石墨烯/玻碳（RGO/GC）电极上电化学氧化连苯三酚来实现。还原氧化石墨烯在催化连苯三酚电化学氧化中起着重要作用。沉积在电极上的深黄色薄膜在很宽的 pH 范围内具有电活性。基于（1）H NMR、（13）C NMR 和 IR 光谱的实验结果，产物中存在羟基、羰基和醛基。产物的紫外-可见光谱中没有可见的吸收峰，其分子量低于二聚体但高于单体。因此，该薄膜既不是聚合物也不是二聚体，只是连苯三酚与氧自由基氧化的产物。在 RGO/石墨电极上沉积的电生成膜的 ESR 信号强度在 210 天后没有观察到衰减的趋势。基于 ESR 信号强度，电生成膜被用作自由基源，以测试水溶液中抗坏血酸、儿茶素和邻苯二酚的自由基清除能力。结果表明，抗坏血酸和儿茶素可以清除自由基，但邻苯二酚几乎不能清除自由基。
