Cuprous oxide nanocubes for simultaneous electrochemical detection and photocatalytic degradation of para-chloronitrobenzene

Abstract

Para-chloronitrobenzene (PCNB) is a widely used nitro-aromatic compound as well as a highly hazardous environmental contaminant. Hence, sensing of PCNB at low concentration, and its eradication still remain challenging. Therefore, this research reports fabrication of cuprous oxide (Cu2O) nanocubes (NCs, 35–45 nm) using a very simple in-situ nucleation method. Such synthesized Cu2O NCs were utilized for fabricating Cu2O NCs/Au electrode to detect PCNB in aqueous samples, and further for PCNB degradation based on photo-catalysis. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) approaches were utilized to examine the effects of various parameters like coating amount, scan rate, pH and analyte concentration. Further, the estimation of analytical parameters through amperometry revealed appreciable electrode sensitivity (4.53 µA µM−1 cm−2), wide linear range (8.0–40.0; 40.0–285.7 µM) and nanomolar limit of detection (24.3 nM) for PCNB at neutral pH. The Cu2O NCs/Au sensor demonstrates remarkable reusability and proffers selective PCNB detection with reproducible results in lab samples and real water. Apart from efficient sensing of PCNB, the Cu2O NCs also catalyzed the photodegradation of PCNB and resulted in ∼ 92% and ∼ 68.5% degradation after 120 min exposure under UV-LED and visible light (500 W), respectively, in neutral pH water samples. Additionally, the Cu2O NCs also offer efficient detection and degradation of PCNB in real water samples. Further, the assessment of phytotoxicity of the Cu2O NCs, reveal their environmentally benign nature. Thus, the Cu2O NCs can be utilized for simple, safe, cost-effective, and label-free PCNB sensor-fabrication as well as for remediation of PCNB from aqueous medium.