Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Sep 2;13(17):2481.
doi: 10.3390/nano13172481.

Microwave-Assisted Synthesis of Pt/SnO2 for the Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol

Izabela Đurasović  1 , Goran Štefanić  1 , Goran Dražić  2 , Robert Peter  3 , Zoltán Klencsár  4 , Marijan Marciuš  5 , Tanja Jurkin  6 , Mile Ivanda  1 , Sándor Stichleutner  4 , Marijan Gotić  1
Affiliations

Microwave-Assisted Synthesis of Pt/SnO2 for the Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol

Izabela Đurasović et al. Nanomaterials (Basel). .

Abstract

In this study, we present a new approach for the synthesis of Pt/SnO2 catalysts using microwave radiation. Pt(IV) and Sn(IV) inorganic precursors (H2PtCl6 and SnCl4) and ammonia were used, which allowed the controlled formation of platinum particles on the anisotropic SnO2 support. The synthesized Pt/SnO2 samples are mesoporous and exhibit a reversible physisorption isotherm of type IV. The XRD patterns confirmed the presence of platinum maxima in all Pt/SnO2 samples. The Williamson-Hall diagram showed SnO2 anisotropy with crystallite sizes of ~10 nm along the c-axis (< 00l >) and ~5 nm along the a-axis (< h00 >). SEM analysis revealed anisotropic, urchin-like SnO2 particles. XPS results indicated relatively low average oxidation states of platinum, close to Pt metal. 119Sn Mössbauer spectroscopy indicated electronic interactions between Pt and SnO2 particles. The synthesized samples were used for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of excess NaBH4. The catalytic activity of the Pt/SnO2 samples for the reduction of 4-NP to 4-AP was optimized by varying the synthesis parameters and Pt loading. The optimal platinum loading for the reduction of 4-NP to 4-AP on the anisotropic SnO2 support is 5 mol% with an apparent rate constant k = 0.59 × 10-2 s-1. The Pt/SnO2 sample showed exceptional reusability and retained an efficiency of 81.4% after ten cycles.

Keywords: 119Sn Mössbauer; 4-nitrophenol; SnO2; XPS; catalyst; microwave synthesis; platinum.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Figures

Figure 1
Figure 1
XRD patterns of samples SP0, SP1, SP3, SP5, SP10, and SP15.
Figure 2
Figure 2
Williamson-Hall plot of the most prominent well-separated diffraction lines of the SnO2 phase in samples SP0, SP1, SP3, SP5, SP10, and SP15.
Figure 3
Figure 3
SEM images of samples SP1 (a), SP3 (b), SP5 (c), SP10 (d), and SP15 (e) at low magnification were taken with a backscatter detector. Some of the bright spots in sample SP1 (a) corresponding to PtNPs are marked with arrows as an example, while the bright spots in the other samples are not marked.
Figure 4
Figure 4
SEM image of sample SP5. A detail shows urchin-like anisotropic particles.
Figure 5
Figure 5
SEM-EDS results of sample SP1. EDS analyses were taken from two different marked sites showing the platinum-rich region (upper panel) and SnO2-rich region (lower panel).
Figure 6
Figure 6
STEM DF image at low magnification (a); STEM BF image at higher magnification with a SAED image in inset, the powder patterns are indexed to SnO2 (cassiterite) (b); a high-resolution image of SnO2 with an FFT image in the (-11-1) zone (inset) (c); a high-resolution image of several SnO2-NPs with clearly visible lattice fringes (d).
Figure 7
Figure 7
STEM image of sample SP3 (a) and corresponding EDXS elemental mapping images of Sn L edge (b), Pt M edge (c), O K edge (d), and overlay of Sn L, Pt M, and O K edges (e).
Figure 8
Figure 8
Displays nitrogen (N2) gas adsorption (red line, squares) and desorption (blue line, triangles) isotherms for the synthesized samples, along with calculated BET surface areas. The accompanying pore volume distribution offers insights into material porosity.
Figure 9
Figure 9
XPS spectra measured around Sn 3d and Pt 4f core levels of synthesized samples.
Figure 10
Figure 10
Room temperature 119Sn Mössbauer spectra (dots) of the samples SP0–SP15 along with the envelope (solid line) of the Lorentzian quadrupole doublet fitted to it. The fit residual is drawn below the spectra.
Figure 11
Figure 11
119Sn isomer shift (δ) depicted as a function of Pt molar concentration of the samples SP0 to SP15, with vertical error bars indicating the standard statistical error (±1σ).
Figure 12
Figure 12
Time-dependent catalytic reduction process of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) using platinum-decorated SnO2 (SP1 to SP15) samples. The insets present the ln(At/A0) plot against reaction time, showcasing the calculated rate constant values (kapp in s–1) derived from the slopes of the linear segments.
Figure 13
Figure 13
Recyclability (reusability) test of sample SP5 for 10 cycles.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Chen W., Cao J., Yang J., Cao Y., Zhang H., Jiang Z., Zhang J., Qian G., Zhou X., Chen D., et al. Molecular-level insights into the electronic effects in platinum-catalyzed carbon monoxide oxidation. Nat. Commun. 2021;12:6888. doi: 10.1038/s41467-021-27238-z. - DOI - PMC - PubMed
    1. Jeyaraj M., Gurunathan S., Qasim M., Kang M., Kim J. A Comprehensive Review on the Synthesis, Characterization, and Biomedical Application of Platinum Nanoparticles. Nanomaterials. 2019;9:1719. doi: 10.3390/nano9121719. - DOI - PMC - PubMed
    1. Papandrew A.B., Chisholm C.R.I., Elgammal R.A., Özer M.M., Zecevic S.K. Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH2PO4. Chem. Mater. 2011;23:1659–1667. doi: 10.1021/cm101147y. - DOI
    1. Liu D., Li X., Chen S., Yan H., Wang C., Wu C., Haleem Y.A., Duan S., Lu J., Ge B., et al. Atomically dispersed platinum supported on curved carbon supports for efficient electrocatalytic hydrogen evolution. Nat. Energy. 2019;4:512–518. doi: 10.1038/s41560-019-0402-6. - DOI
    1. Haneda M., Watanabe T., Kamiuchi N., Ozawa M. Effect of platinum dispersion on the catalytic activity of Pt/Al2O3 for the oxidation of carbon monoxide and propene. Appl. Catal. 2013;142:8–14. doi: 10.1016/j.apcatb.2013.04.055. - DOI

LinkOut - more resources