Gas Sensors & Sensing Technology Lab, School of of Electrical Engineering and Computer Science and §School of of Electrical Engineering and Computer Science, Ningbo University , Ningbo 315211, P. R. China.
Development Center, Qingdao National Laboatory for Marine Science and Technology , Qingdao 266237, P. R. China.
ACS Sens. 2017 Oct 27;2(10):1467-1473. doi: 10.1021/acssensors.7b00423. Epub 2017 Sep 20.
Inadequate detection limit and unsatisfactory discrimination features remain the challenging issues for the widely applied electrochemical gas sensors. Quite recently, we confirmed that light-regulated electrochemical reaction significantly enhanced the electrocatalytic activity, and thereby can potentially extend the detection limit to the parts per billion (ppb) level. Nevertheless, impact of the light-regulated electrochemical reaction on response selectivity has been discussed less. Herein, we systematically report on the effect of illumination on discrimination features via design and fabrication of a light-regulated electrochemical sensor array. Upon illumination (light on), response signal to the examined gases (CH, NO, and CO) is selectively enhanced, resulting in the sensor array demonstrating disparate response patterns when compared with that of the sensor array operated at light off. Through processing all the response patterns derived from both light on and light off with a pattern recognition algorithm, a satisfactory discrimination feature is observed. In contrast, apparent mutual interference between NO and CO is found when the sensor array is solely operated without illumination. The impact mechanism of the illumination is studied and it is deduced that the effect of the illumination on the discriminating features can be mainly attributed to the competition of electrocatalytic activity and gas-phase reactivity. If the enhanced electrocatalytic activity (to specific gas) dominates the whole sensing progress, enhancements in the corresponding response signal would be observed upon illumination. Otherwise, illumination gives a negligible impact. Hence, the response signal to part of the examined gases is selectively enhanced by illumination. Conclusively, light-regulated electrochemical reaction would provide an efficient approach to designing future smart sensing devices.
对于广泛应用的电化学气体传感器来说，检测限不足和识别特征不理想仍然是具有挑战性的问题。最近，我们证实，受光调控的电化学反应显著提高了电催化活性，从而有可能将检测限扩展到十亿分之一（ppb）的水平。然而，受光调控的电化学反应对响应选择性的影响讨论较少。在此，我们通过设计和制造受光调控的电化学传感器阵列，系统地报告了光照对识别特征的影响。在光照（光开启）下，对所检测气体（CH、NO 和 CO）的响应信号被选择性地增强，使得传感器阵列在与光关闭时的传感器阵列相比表现出不同的响应模式。通过用模式识别算法处理来自光开启和光关闭的所有响应模式，观察到了令人满意的识别特征。相比之下，当传感器阵列在没有光照的情况下单独运行时，发现 NO 和 CO 之间存在明显的相互干扰。研究了光照的影响机制，并推断光照对识别特征的影响主要归因于电催化活性和气相反应性之间的竞争。如果增强的电催化活性（对特定气体）主导整个传感过程，则在光照下会观察到相应响应信号的增强。否则，光照的影响可以忽略不计。因此，一部分被检测气体的响应信号被光照选择性增强。总之，受光调控的电化学反应为设计未来的智能传感设备提供了一种有效的方法。
