Scanning electrochemical microscopy of Belousov-Zhabotinsky reaction: how confined oscillations reveal short lived radicals and auto-catalytic species.
Scanning electrochemical microscopy of Belousov-Zhabotinsky reaction: how confined oscillations reveal short lived radicals and auto-catalytic species.
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Belousov-Zhabotinsky 反应的扫描电化学显微镜：受限振荡如何揭示短命自由基和自催化物质。
DOI：
10.1021/acs.analchem.5b01238
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发表时间：
2015
影响因子：
7.4
通讯作者：
F. Kanoufi
中科院分区：
文献类型：
--
作者：
T. Stockmann;Jean‐Marc Noël;S. Ristori;C. Combellas;A. Abou;F. Rossi;F. Kanoufi
封装在人造囊泡内的振荡化学反应已被证明可以作为活细胞的有力类比，用于研究化学通讯和形态发生。然而，人们对限制对此类系统反应性的影响知之甚少。在此，使用扫描电化学显微镜 (SECM) 对不同的绝缘表面（例如玻璃、硅烷化玻璃或 PTFE）研究了本体溶液（使用铁蛋白作为催化剂，丙二酸作为有机底物）中限制对 Belousov-Zhabotinsky (BZ) 振荡反应的影响。观察到尖端-基底距离~12-15 μm 时 BZ 反应振幅意外增加。通过模拟不同的反应机制，从简单的 EC' 催化到更复杂的 Oregonator 甚至 11 反应方案，结果表明这种行为揭示了氧化还原催化过程的干预，特别是在微摩尔浓度下间接检测到的短寿命的高活性自由基中间体 BrO2(•)。对EC'机制的重新检查表明，从SECM到绝缘基底的均相催化路线已得到证实并具有动力学特征，在许多系统中具有广阔的潜力。更具体地说，对于 BZ 反应的复杂化学情况，可以从振荡的包络曲线来理解其机制，该包络曲线是在没有振荡（没有有机底物）的情况下进行评估的。
Oscillating chemical reactions, encapsulated within artificial vesicles have been demonstrated as a powerful analogy of living cells for the investigation of chemical communication and morphogenesis. However, little is understood with regards to the influence of confinement on the reactivity of such systems. Herein, the effect of confinement on the Belousov-Zhabotinsky (BZ) oscillating reaction in bulk solution, (employing ferroin as a catalyst and malonic acid as the organic substrate) is investigated using scanning electrochemical microscopy (SECM) toward different insulating surfaces such as glass, silanized glass, or PTFE. An unexpected increase in the amplitude of the BZ reaction at a tip-substrate distance of ∼12-15 μm is observed. By simulating different reaction mechanisms, from simple EC' catalysis to more sophisticated Oregonator or even an 11-reaction scheme, it is shown that such behavior reveals the intervention of redox catalysis processes and particularly the short-lived highly reactive radical intermediate BrO2(•) indirectly detected at micromolar concentrations. The reinspection of the EC' mechanism shows that the homogeneous catalysis route is confirmed and kinetically characterized from SECM toward an insulating substrate, with promising potentiality in many systems. More specifically to the complex chemical case of BZ reactions, the mechanism is understood from the envelope curves of the oscillations, which are assessed in the absence of the oscillation (absence of organic substrate).
影响因子：
4
作者：
Luo, Tianzhi;Srivastava, Vasudha;Robinson, Douglas N.
通讯作者：
Robinson, Douglas N.