Romano R L, Damaceno L P, Magalhães D V, Parmananda P, Varela H
São Carlos Institute of Chemistry, University of São Paulo, 13560-970 São Carlos, SP, Brazil.
Department of Mechanical Engineering, University of São Paulo, 13560-970 São Carlos, SP, Brazil.
Chaos. 2022 Aug;32(8):083139. doi: 10.1063/5.0098339.
The catalytic electro-oxidation of some small organic molecules is known to display kinetic instabilities, which reflect on potential and/or current oscillations. Under oscillatory conditions, those systems can be considered electrocatalytic oscillators and, therefore, can be described by their amplitude, frequency, and waveform. Just like mechanical oscillators, the electrocatalytic ones can be coupled and their dynamics can be changed by setting different coupling parameters. In the present work, we study the unidirectional coupling of electrocatalytic oscillators, namely, those comprehending the catalytic electro-oxidation of methanol and formic acid on polycrystalline platinum in acidic media under potentiostatic control. Herein, we explore two different scenarios (the coupling of compositionally identical and non-identical oscillators) and investigate the effects of the master's identity and of the coupling constant on the slave's dynamics. For the master (methanol)-slave (methanol) coupling, the oscillators exhibited phase lag synchronization and complete phase synchronization. On the other hand, for the master (formic acid)-slave (methanol) coupling, the oscillators exhibited complete phase synchronization with phase-locking with a 2:3 ratio, complete phase synchronization with phase-locking with a 1:2 ratio, phase lag synchronization, and complete phase synchronization. The obtained results suggest that both the master's identity and the coupling constant (sign and magnitude) are parameters that play an important role on the coupled systems, in such a way that even for completely different systems, synchronization could emerge by setting a suitable coupling constant. To the best of our knowledge, this is the first report concerning the electrical coupling of hidden N-shaped-negative differential resistance type systems.
已知一些小分子有机化合物的催化电氧化会表现出动力学不稳定性，这反映在电势和/或电流振荡上。在振荡条件下，这些系统可被视为电催化振荡器，因此，可以用它们的振幅、频率和波形来描述。就像机械振荡器一样，电催化振荡器可以耦合，并且可以通过设置不同的耦合参数来改变它们的动力学。在本工作中，我们研究了电催化振荡器的单向耦合，即在恒电位控制下，在酸性介质中多晶铂上甲醇和甲酸的催化电氧化。在此，我们探索了两种不同的情况（组成相同和不同的振荡器的耦合），并研究了主振荡器的特性和耦合常数对从振荡器动力学的影响。对于主（甲醇）-从（甲醇）耦合，振荡器表现出相位滞后同步和完全相位同步。另一方面，对于主（甲酸）-从（甲醇）耦合，振荡器表现出完全相位同步且锁相比例为2:3、完全相位同步且锁相比例为1:2、相位滞后同步以及完全相位同步。所得结果表明，主振荡器的特性和耦合常数（符号和大小）都是对耦合系统起重要作用的参数，以至于即使对于完全不同的系统，通过设置合适的耦合常数也可能出现同步。据我们所知，这是关于隐藏N形负微分电阻型系统电耦合的首次报道。
