Efficient Heterostructures of Ag@CuO/BaTiO₃ for Low-Temperature CO₂ Gas Detection: Assessing the Role of Nanointerfaces during Sensing by Operando DRIFTS Technique

Abstract

Tetragonal BaTiO spheroids synthesized by a facile hydrothermal route using Tween 80 were observed to be polydispersed with a diameter in the range of ∼15-75 nm. Thereon, BaTiO spheroids were decorated with different percentages of Ag@CuO by wet impregnation, and their affinity toward carbon dioxide (CO) gas when employed as sensitive layers in a microsensor was investigated. The results revealed that the metal nanocomposite-based sensor had an exceptional stability and sensitivity toward CO gas (6-fold higher response), with appreciable response and recovery times (<10 s) and higher repeatability (98%) and accuracy (96%) at a low operating temperature of 120 °C, compared to those of pure BaTiO and CuO. Such improved gas-sensing performances even at a very low concentration (∼700 ppm) is attributable to both the chemical and electrical contributions of Ag@CuO forming intermittent nanointerfaces with BaTiO spheroids, exhibiting unique structural stability. The CO-sensing mechanism of CuO/BaTiO nanocomposite was studied by the diffuse reflectance infrared Fourier transform spectroscopy technique that established the reaction of CO with BaO and CuO to form the respective carbonate species that is correlated with the change in material resistance consequently monitored as sensor response.

Self‐Polarized BaTiO3 for Greatly Enhanced Performance of ZnO UV Photodetector by Regulating the Distribution of Electron Concentration

“…Barium titanate (BaTiO 3 , BTO), a well‐known ferroelectric material having high dielectric constant, low dielectric loss, and promising ferroelectric properties, has been exploited in many applications such as gas sensing, waveguide modulators, pressure transducers, capacitors, and memory devices . In addition, BTO film can be prepared by a simple sol–gel spin‐coating method, which is compatible with the preparation of ZnO film.…”

Nanostructured Gas Sensors: From Air Quality and Environmental Monitoring to Healthcare and Medical Applications

“…In another approach, a hybrid heterostructure made of tetragonal n-type BaTiO 3 spheroids decorated with p-type CuO micro-leaves ( Figure 3 i, inset) was synthesized by a simple hydrothermal method [ 49 ], demonstrating an exceptional stability and sensitivity toward CO 2 gas compared to pure BaTiO 3 device ( Figure 3 i). The BaTiO 3 has a large bandgap of 3.1–3.3 eV with a high carrier concentration of up to 7 × 10 21 cm −3 with minimal lattice mismatch with CuO (<2%), making them promising pairs for the formation of hybrid heterostructure [ 50 , 51 ].…”

“…The BaTiO 3 has a large bandgap of 3.1–3.3 eV with a high carrier concentration of up to 7 × 10 21 cm −3 with minimal lattice mismatch with CuO (<2%), making them promising pairs for the formation of hybrid heterostructure [ 50 , 51 ]. The p–n junction formation results in creating electronic interaction and change in work function of sensing materials, which leads to reduction in the energy barrier at the grain boundary of BaTiO 3 and CuO [ 49 ]. This leads to the formation of a smaller depletion layer and subsequently, higher sensing response upon exposure to CO 2 gas molecules.…”

Recent advances in ABO3 perovskites: their gas-sensing performance as resistive-type gas sensors

“…Apart from doping of A and/or B site in ABO 3 perovskites or combination with metal oxides, catalysts loading on these perovskite oxides can provide specific adsorption sites for oxygen adsorption and catalytic centers for oxidation of analyte gases to improve sensors response, speed, selectivity, and operating temperature. Thus far, various perovskite oxides have been loaded with various catalysts such as silver (Ag) [62][63][64], palladium (Pd) [65,66], and Au [67] for gas-sensing applications. These catalysts can physically or chemically interact with the surface of perovskite oxides depending on synthesis conditions and nature of catalysts.…”

“…The introduced defects provided more holes, leading to high charge carrier concentration and enhancement of formaldehyde sensing. Joshi et al [64] prepared Ag@ CuO-decorated BaTiO 3 spheroids by wet impregnation and hydrothermal techniques, and investigated their sensing affinity to CO 2 . Here, intermittent p-n heterojunctions were formed upon co-precipitation of CuO microleaves with BaTiO 3 spheroids.…”