PDF(Sci-hub)
Abstract：
Developing photoelectrochemical (PEC) sensors based on photocatalytic materials has recently attracted great interest as an emerging technology for environmental monitoring. TiO2 P25 is a well-known highly active photocatalyst, cheap, and produced commercially on a large scale. In the current work, a practical and durable TiO2-based PEC sensor has been fabricated by immobilizing TiO2 P25 nanoparticles at disposable screen-printed carbon substrates using drop-casting method. The fabricated PEC sensor has been applied for the anodic-detection and determination of nitrite (NO2-) ions under UV(A) light (LED, 365 nm) using chronoamperometry (CA) and differential pulse voltammetry (DPV). Linear calibration curves were obtained between the photocurrent responses and the concentrations of NO2- ions in the ranges of 0.1-5.0 and 0.5-10 mg L-1 for CA and DPV, respectively. Surprisingly, the detection limits (sensitivities) of the fabricated sensor towards NO2- ions under light were enhanced by a factor of 4.75 (4.1) and 8.3 (37.4) for CA and DPV, respectively, in comparsion with those measured in the dark. It is found that the photo-excitation of TiO2 facilitates the photooxidation of NO2- ions via the photo-generated holes whereas the photogenerated electrons contribute to the enhanced photocurrent and consequently the enhanced detection limit and sensitivity. The fabricated TiO2-based PEC sensor exhibits a good stability, durability, and satisfying selectivity for NO2- ions determination. These results indicate that the TiO2-based PEC sensor fabricated by utilizing cheap and commercially available components has great potential for being transferred from lab-to-factory.
摘要：
开发基于光催化材料的光电化学（PEC）传感器作为环境监测的新兴技术最近引起了极大的兴趣。TiO2P25是一种众所周知的高活性光催化剂，便宜,并大规模商业化生产。在目前的工作中,一种实用且耐用的基于TiO2的PEC传感器是通过使用滴注法将TiO2P25纳米颗粒固定在一次性丝网印刷的碳基材上而制成的。制造的PEC传感器已用于在UV（A）光（LED，365nm）使用计时电流法（CA）和差分脉冲伏安法（DPV）。对于CA和DPV，光电流响应与NO2-离子浓度之间的线性校准曲线在0.1-5.0和0.5-10mgL-1范围内，分别。令人惊讶的是,对于CA和DPV，制造的传感器在光照下对NO2-离子的检测限（灵敏度）提高了4.75（4.1）和8.3（37.4），分别,与在黑暗中测量的相比。发现TiO2的光激发促进了NO2-离子通过光生空穴的光氧化，而光生电子则有助于增强光电流，从而提高检测极限和灵敏度。制备的TiO2基PEC传感器具有良好的稳定性,耐用性,并满足NO2-离子测定的选择性。这些结果表明，通过利用廉价和市售组件制造的基于TiO2的PEC传感器具有从实验室转移到工厂的巨大潜力。
