Ultrasensitive simultaneous determination of hydroquinone and catechol by Ni3ZnC0.7/Ni porous composites derived from Ni/Zn-MOF

Rational constructing metal-organic frameworks (MOFs) based composite materials with outstanding catalytic capability is vital to accomplish high -performance electrochemical sensors. In this paper, the precursor Ni/ZnMOF was fabricated by a simple one-step solvothermal method, and then the Ni nanoparticle-supported porous microsphere composites (Ni3ZnC0.7/Ni) were obtained by pyrolysis in N2 atmosphere. The physicochemical characteristics of the as-prepared Ni3ZnC0.7/Ni were studied by XRD, SEM, EDS, TEM, FTIR and XPS, and their electrocatalytic activity were tested by Cyclic voltammetry (CV) and differential pulse voltammetry (DPV). On this basis, an electrochemical sensor strategy for the simultaneous determination of hydroquinone (HQ) and catechol (CC) with Ni3ZnC0.7/Ni modified glassy carbon electrode (GCE) was proposed. In addition, they were applied to the electrochemical simultaneous detection of HQ and CC for the first time. Compared with NiC and ZnC modified electrode, the Ni3ZnC0.7/Ni composites modified electrode can significantly enhance electrocatalytic activity and improve the selectivity and sensitivity of the detection of HQ and CC. The performance was due to increasing the active surface area of the modified electrode and the Ni atom has excellent electrocatalytic capability to dihydroxybenzene. The experimental results exhibits that the composite was used to achieve simultaneous detection of HQ and CC in single-component or two-component solutions with satisfactory result. It has a low limit of detections (LOD = 3 sigma/k) (HQ: 0.14 mu M, CC: 0.21 mu M) and a wide detection range (HQ: 0.3-100.0 mu M, CC: 0.5-100.0 mu M). Meanwhile, the constructed sensor has been successfully employed for determination of HQ and CC in Yellow River water and tap water, and obtains good recovery rate. This work develops a new approach for design and engineering of MOF materials for electrochemical sensors and environmental monitoring.