Band gap tailoring and photosensitivity study of Al-doped SnO2 nanocrystallites prepared by sol–gel technique

Panda, Binod Bihari; Tripathy, Debakanta; Maity, N. P.

doi:10.1007/s10854-022-09167-9

Cited by 2 publications

(1 citation statement)

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“…Powder X-ray diffraction (PXRD) of the nanomaterials was conducted using a Rigaku diffractometer (40 kV and 40 mA) equipped with Cu Kα radiation (λ = 1.54 Å) at a scanning rate 4°/min and within a 2θ range of 10–110°. The average crystallite sizes ( D ) of Pd, Ag, and Pd x Ag y in Pd 100 /FA, Pd 87.5 Ag 12.5 /FA, Pd 75 Ag 25 /FA, Pd 50 Ag 50 /FA, Pd 25 Ag 75 /FA, Pd 12.5 Ag 87.5 /FA, and Ag 100 /FA were evaluated using the Debye–Scherrer equation D = K λ/(β cos θ), where K is the Scherrer constant (0.89), λ is the X-ray wavelength (0.154 nm), β is the full-width at half-maxima of the diffraction peak, and θ is the diffraction angle. − Advanced PHI-5000 Versa-probe setup was used to perform an X-ray photoelectron spectroscopic (XPS) study. The binding energies were referenced to the adventitious C 1s peak at 284.8 eV .…”

Section: Methodsmentioning

confidence: 99%

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles

Maity,

Mishra,

Barman

et al. 2023

ACS Omega

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Fly ash (FA)-supported bimetallic nanoparticles (Pd x Ag y /FA) with varying Pd:Ag ratios were prepared by coprecipitation of Pd and Ag involving in situ reduction of Pd(II) and Ag(I) salts in aqueous medium. All the supported nanoparticles were thoroughly characterized with the aid of powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), electron microscopy (field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM)), and elemental analyses, which include inductively coupled plasma-optical emission spectroscopy (ICP-OES) and energy-dispersive X-ray spectroscopy (EDS). A gradual broadening and shifting of PXRD peaks, ascribable to Ag, to higher angles with an increase in the Pd:Ag ratio affirms the alloying of interface between Pd and Ag nanoparticles. The coexistence of Pd and Ag was further confirmed by EDS elemental mapping as well as by the presence of bimetallic lattices on the FA surface, as evident from the high-resolution TEM analysis. The dependency of crystallite size and average size of bimetallic nanoparticles on Ag loading (mol %) was elucidated with the help of a combination of PXRD and TEM studies. Based on XPS analysis, the charge transfer phenomenon between contacting Pd−Ag sites could be evident from the shifting of 3d core electron binding energy for both Pd and Ag compared with monometallic Pd and Ag nanoparticles. Following a pseudo-first-order reaction kinetics, all the nanocatalysts were able to efficiently reduce 4-nitrophenol into 4-aminophenol in aqueous NaBH4. The superior catalytic performance of the bimetallic nanocatalysts (Pd x Ag y /FA) over their monometallic (Pd100/FA and Ag100/FA) analogues has been demonstrated. Moreover, the tunable synergistic effect of the bimetallic systems has been explored in detail by varying the Pd:Ag mol ratio in a systematic manner which in turn allowed us to achieve an optimum reaction rate (k = 1.050 min–1) for the nitrophenol reduction using a Pd25Ag75/FA system. Most importantly, all the bimetallic nanocatalysts explored here exhibited excellent normalized rate constants (K ≈ 6000–15,000 min–1 mmol–1) compared with other supported bimetallic Pd–Ag nanocatalysts reported in the literature.

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Section: Methodsmentioning

confidence: 99%

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles

Maity,

Mishra,

Barman

et al. 2023

ACS Omega

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Impact of Copper Doping on Nanocrystalline SnO<sub>2</sub> Thin Films Synthesized by Sol-Gel Coating and Chemical Bath Deposition for Gas Sensor Applications

AL-Jawad,

Rasheed,

Ibrahim

et al. 2024

JNanoR

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This work focuses on the preparation of pure nanocrystalline SnO2 and SnO2:Cu thin films on cleaned glass substrates utilizing a sol-gel spin coating and chemical bath deposition (CBD) procedures. The primary aim of this study is to investigate the possible use of these thin films in the context of gas sensor applications. The films underwent annealing in an air environment at a temperature of 500 ◦C for duration of 60 minutes. The thickness of the film that was deposited may be estimated to be around 300 nm. The investigation included an examination of the structural, optical, electrical, and sensing characteristics, which were explored across various preparation circumstances, specifically focusing on varied concentrations of Cu-doping (2, 4, and 6 wt.%). The deposited films were analyzed by several techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical absorption spectroscopy. The films generated by the spin coating method had a tetragonal rutile structure, while the films created via the chemical bath deposition (CBD) technique displayed both tetragonal rutile and orthorhombic structures. The spin coating technique was used to make films of several weight percentages (0, 2, 4, and 6 wt.%). The resulting crystallite sizes were examined and found to be 23 nm, 18 nm, 14 nm, and 10.5 nm, respectively. Similarly, films made using the chemical bath deposition (CBD) method exhibited crystallite sizes of 22, 13.9, 9.3, and 8.15 nm, respectively. The obtained findings from atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses indicate a consistent trend whereby, as the concentration of Cu-doped material rises, there is a decrease in the average grain size. The transmittance and absorbance spectra were examined within the wavelength range of 300 to 1000 nm. The films generated by both approaches exhibit a significant level of light transmission throughout the visible spectrum. The bandgap energy of spin coating and CBD films decreases with increasing Cu-doped concentrations; the values were (3.88, 3.8, 3.68, and 3.63) eV and (3.8, 3.78, 3.66, and 3.55) eV, respectively. The electrical characteristics of the films include direct current (DC) electrical conductivity, which indicates the presence of two activation energies, Ea1 and Ea2. These activation energies exhibit an upward trend when the concentration of Cu doping is increased. The films were examined for their ability to detect carbon monoxide (CO) gas at a concentration of about 50 ppm at normal room temperature conditions. The sensitivity of the films to carbon monoxide (CO) gas was assessed at various time intervals and temperatures. The results indicated that the film generated using spin coating exhibited a notably high sensitivity at a temperature of 200 °C, while the film prepared using the chemical bath deposition (CBD) approach had heightened sensitivity at a temperature of 150 °C. Keywords: Spin coating, SnO2 thin films, CBD, AFM, XRD, gas sensor.

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Band gap tailoring and photosensitivity study of Al-doped SnO2 nanocrystallites prepared by sol–gel technique

Cited by 2 publications

References 62 publications

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles

Impact of Copper Doping on Nanocrystalline SnO<sub>2</sub> Thin Films Synthesized by Sol-Gel Coating and Chemical Bath Deposition for Gas Sensor Applications

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Band gap tailoring and photosensitivity study of Al-doped SnO2 nanocrystallites prepared by sol–gel technique

Cited by 2 publications

References 62 publications

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported PdxAgy Bimetallic Nanoparticles

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported PdxAgy Bimetallic Nanoparticles

Impact of Copper Doping on Nanocrystalline SnO<sub>2</sub> Thin Films Synthesized by Sol-Gel Coating and Chemical Bath Deposition for Gas Sensor Applications

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Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles

Tuning Pd-to-Ag Ratio to Enhance the Synergistic Activity of Fly Ash-Supported Pd_xAg_y Bimetallic Nanoparticles