Pt‐Functionalized Nanoporous TiO₂ Nanoparticles With Enhanced Gas Sensing Performances Toward Acetone

Abstract

A facile hydrothermal method is used to prepare Pt-functionalized nanoporous TiO 2 nanoparticles. These are used as gas-sensing material in sensors, fabricated according to the indirect heating method. Gas-sensing performance of the sensors is investigated by testing their gas response to acetone, which exhibits favorable selectivity, good gas response value, fast response/recovery time, low detection concentration and good long-term stability to acetone. Gas response β was defined as the ratio of R a /R g , where R a and R g are the resistance values of gas sensor exposed in air and objective gas, respectively. Among all these as-prepared gas sensors, the 0.5% Pt-functionalized TiO 2 based gas sensor shows the highest gas response value of 29.51-200 ppm acetone at 300 C, and the gas response value is 5.2 times higher than that (5.67) of pure TiO 2 based gas sensor. It also has excellent selectivity to acetone when comparing with toluene, n-butanol, isopropanol, ethanol, and methanol. The large specific surface area (168.101 m 2 g À1 ) provides enough contacting interface between gas and the as-prepared materials, then the gas molecules could be broken into CO 2 and H 2 O by the active adsorbed oxygen species. The present results of the Ptfunctionalized TiO 2 based gas sensors illustrates their potential application in detecting acetone.

Review: Influences of Semiconductor Metal Oxide Properties on Gas Sensing Characteristics

“…The NMs, such as Ag, Au, Pd, Pt, and Rh NPs loaded/decorated onto the surfaces of semiconducting SnO 2 and TiO 2 enhance the gas sensing performance, due to the creation of new active centers on the MOx surface or changing the electronic structure of material (Epifani et al, 2012). As the alteration of electronic structure changes the electron accumulation due to the different work functions between NMs and semiconducting oxide (Chen et al, 2017), the chemical sensitization relies on effective catalytic properties of NMs (Xing et al, 2018).…”

Fabrication of AgCu/TiO2 nanoparticle-based sensors for selective detection of xylene vapor

“…Studies have revealed that doping TiO 2 with noble metals (e.g., Pt, Au, Pd, and Ag) or transition metals (e.g., Cu, and Zn) enhances the sensing characteristics, as they can regulate the morphology, enable surface reactions, transform the space charge distribution, and hence, advance the gas sensing characteristics. [5][6][7][8] Lupan et al [9] reported role of film thickness and surface functionalization using noble metals nanoclusters on the gas sensing performance of ultra-thin TiO 2 layers. Their TiO 2 ultra-thin films exhibited superior selectivity towards hydrogen gas, without being reliant on their thickness.…”

“…[20] Therefore, appropriate, and selective detection of BTEX vapours, predominantly at minimal concentrations, is very vital, efficient farming with capable conveyance and Page5 storage may be realized. Though several studies exist on the loading of noble metals on various SMOs [1,[6][7][8][9][10][11][12][13][14][15] , however, to the best of our information, no study has been conducted on the gas sensing properties of TiO 2 nanoparticles loaded with AgCu nanoparticles. In the current work, we show that a higher loading of both Ag/Cu switches the conductivity of TiO 2 from p-type to n-type, where such switching is not temperature or gas dependent.…”

Use of nanostructured and modified TiO2 as a gas sensing agent

“…The use of Pt in TiO 2 is also reported as a noble metal that favors the sensitivity of TiO 2 for the detection of other gases [99,100]. Xing et al [101] synthesized via hydrothermal method (5.67). The authors [101] attributed this better performance of the Pt/TiO 2 sensor to the catalytic effect of Pt, which increases the ability to absorb oxygen molecules and accelerate the reaction between adsorbed oxygen species (O x -) and acetone gas molecules, as well as the fact that Pt atoms introduce an intermediate energy level in the bandgap, making it easier for excited electrons to migrate from the valence band to conduction band.…”

“…Xing et al [101] synthesized via hydrothermal method (5.67). The authors [101] attributed this better performance of the Pt/TiO 2 sensor to the catalytic effect of Pt, which increases the ability to absorb oxygen molecules and accelerate the reaction between adsorbed oxygen species (O x -) and acetone gas molecules, as well as the fact that Pt atoms introduce an intermediate energy level in the bandgap, making it easier for excited electrons to migrate from the valence band to conduction band. Abe et al [102] also reported that the introduction of Pt on the surface of TiO 2 favors the detection of gases (hydrogen, carbon monoxide).…”