Periodate – an alternative oxidant for testing potential water oxidation catalysts
Periodate – an alternative oxidant for testing potential water oxidation catalysts
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高碘酸盐 – 用于测试潜在水氧化催化剂的替代氧化剂
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
C. O’Rourke
中科院分区：
文献类型：
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作者：
A. Mills;David Hazafy;S. Elouali;C. O’Rourke
通过亚当斯技术制备的氧化还原催化剂二氧化钌，即Ru（亚当斯），用作水氧化催化剂，使用氧化剂（i）在0.5 M H2SO 4中的Ce（IV）和（ii）在0.5 M H2SO 4、水和0.1 M KOH中的高碘酸盐。与Ce（IV）一样，高碘酸盐是一种非常强的氧化剂，能够将水氧化成氧气，并且可以在280 nm处容易地进行监测，而Ce（IV）的监测波长为430 nm。更重要的是，与Ce（IV）不同，Ce（IV）在pH 1以上对水解不稳定，高碘酸盐在酸、水和强碱中稳定。高碘酸盐还原动力学的分光光度法研究，以及伴随的水氧化成O2，揭示了在合适的氧化还原催化剂Ru（亚当斯）的存在下，高碘酸盐能够影响水的化学计量氧化，其转化数> 48。仅在水中，后一反应的动力学似乎是扩散控制的，这是由于大的热力学驱动力，其测量是氧化还原电位的差异，即ΔE = 423 mV。随着这一差异的减小，ΔE在酸中为396 mV，在强碱（0.1 M KOH）中为290 mV，动力学变得越来越受活化控制，并且变慢。这些发现简要讨论了关于（i）高碘酸盐作为替代氧化剂在快速筛选仅在近中性和/或碱性条件下稳定的新的潜在水氧化催化剂材料粉末中的可能用途，和（ii）Ru（亚当斯）作为基准催化剂。
The redox catalyst ruthenium dioxide, prepared via the Adams technique, i.e. Ru(Adams), is used as a water oxidation catalyst using the oxidants (i) Ce(IV) in 0.5 M H2SO4 and (ii) periodate in 0.5 M H2SO4, water and 0.1 M KOH. Like Ce(IV), periodate is a very strong oxidant that is able to oxidise water to oxygen and can be readily monitored spectrophotometrically at 280 nm, compared with 430 nm for Ce(IV). More importantly, unlike Ce(IV), which is unstable towards hydrolysis above pH 1, periodate is stable in acid, water and strong alkali. A spectrophotometric study of the kinetics of periodate reduction, and concomitant oxidation of water to O2, reveals that in the presence of a suitable redox catalyst, Ru(Adams) in this work, periodate is able to effect the stoichiometric oxidation of water, with a turnover number > 48. In just water, the kinetics of the latter reaction appear diffusion-controlled, due to the large thermodynamic driving force, a measure of which is the difference in redox potential, i.e. ΔE = 423 mV. As this difference is decreased, ΔE = 396 mV in acid and 290 mV in strong alkali (0.1 M KOH), the kinetics become increasingly activation-controlled and slower. These findings are discussed briefly with regard to the possible use of (i) periodate as an alternative oxidant in the rapid screening of new potential water oxidation catalyst material powders that are stable only under near neutral and/or alkaline conditions, and (ii) Ru(Adams) as a benchmark catalyst.