pH-modulated peroxidase-like PtNi nanowires-colorimetric “chemical nose” sensor array for detection and identification of thiophene compounds

Electronic tongue capable of identifying thiophene compounds can promote early-stage environmental pollution monitoring and assist in environmental governance. Herein, a pH-modulated colorimetric sensor array based on PtNi nanowires (NWs) with peroxidase-like activity is designed for discrimination of thiophene compounds. The simplicity of the construction of this sensor array lies in the fact that it is composed of only one nanomaterial-3,3′,5,5′-tetramethylbenzidine (TMB)-H2O2 system at three different pH values, which largely simplifies the programmatic design of the sensor array. Besides, in terms of sensing principle, the adsorption of sulfur from thiophene compounds on PtNi NWs alters the electronic state of their active centers, resulting in different peroxidase-like activities at different pH values. The color variances brought by the changes serve as "fingerprints" to successfully recognize six thiophene compounds as low as 1 µM level. Notably, PtNi NWs show splendid peroxidase-like activity (12.66 U/mg), far outweighing that of Pt NWs (2.62 U/mg), thanks to synergistic catalytic effect of Pt and Ni.