Buffer Assists Electrocatalytic Nitrite Reduction by a Cobalt Macrocycle Complex
Buffer Assists Electrocatalytic Nitrite Reduction by a Cobalt Macrocycle Complex
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DOI：
10.1021/acs.inorgchem.2c00909
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发表时间：
2022-08-10
影响因子：
4.6
通讯作者：
Smith, Jeremy M.
中科院分区：
文献类型：
--
作者：
Braley, Sarah E.;Kwon, Hyuk-Yong;Smith, Jeremy M.
这项工作报告了一个综合的实验和计算研究的活化，否则催化惰性的钴配合物，[Co（TIM）-Br 2]+，水溶液中的亚硝酸盐还原。磷酸盐缓冲液的存在导致有效的电催化，快速还原为铵发生接近热力学势和高法拉第效率。在中性pH下，增加缓冲液浓度增加催化电流，同时降低过电位，尽管高浓度具有抑制作用。控制电位电解和旋转环盘电极实验表明，[Co（TIM）Br-2]（+）与羟胺沿着直接从亚硝酸盐中生成铵。机制研究暗示了磷酸盐缓冲液的重要作用，特别是作为质子穿梭，虽然高缓冲液浓度抑制催化。这些结果表明缓冲剂在氮氧化物转化电催化剂设计中的作用。
This work reports a combined experimental and computational study of the activation of an otherwise catalytically inactive cobalt complex, [Co(TIM)-Br2]+, for aqueous nitrite reduction. The presence of phosphate buffer leads to efficient electrocatalysis, with rapid reduction to ammonium occurring close to the thermodynamic potential and with high Faradaic efficiency. At neutral pH, increasing buffer concentrations increase catalytic current while simultaneously decreasing overpotential, although high concentrations have an inhibitory effect. Controlled potential electrolysis and rotating ring-disk electrode experiments indicate that ammonium is directly produced from nitrite by [Co(TIM)Br-2](+), along with hydroxylamine. Mechanistic investigations implicate a vital role for the phosphate buffer, specifically as a proton shuttle, although high buffer concentrations inhibit catalysis. These results indicate a role for buffer in the design of electrocatalysts for nitrogen oxide conversion.