Engineering electronic band structure of ternary thermoelectric nanocatalysts for highly efficient detection of hydrogen sulfide

Abstract

Colorimetric visual sensor has emerged as an appealing toolkit to monitor distinct molecules owing to its unique merits of naked-eye readout, spatiotemporal selectivity and fast detection. However, the catalytic efficiency of nanozymes and single-signal output remains relatively low or false results. To address this limitation, a high-performance pyroelectric nanocatalyst, PtTeCu nanorods (NRs), with excellent pyroelectric/photothermal conversion performance and peroxidase–mimic activity for hydrogen sulfide (H₂S) detection, is developed by colorimetry, photothermal, and a smartphone triple-signal sensing platform. Shape-controllable binary PtTe NRs are reconstructed by inserting a third element, Cu, which could boost the heterostructure formation of PtTeCu NRs with promoted pyrocatalytic conversion efficiency, thereby displaying superior peroxidase–mimic activity under 808 nm irradiation. Typically, assisted by intrinsic catalytic activity, PtTeCu NRs can oxidize colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to form a blue product of oxidized TMB (oxTMB) with near-infrared (NIR) absorption, endowing NIR-driven colorimetry and photothermal assay with high absorbance intensity at 652 nm utilizing portable UV-Vis instrument and thermometer. Based on the significant inhibition effect of H₂S on oxTMB activity, a robust, simple, portable, accurate and on-site assay with a low limit of detection of 0.42 μM is established by complementary colorimetry, photothermal, and smartphone sensors. This work opens an avenue for the design of high-performance nanozymes by reconstructing binary nanocatalysts and accurate detection in biomedical applications.