SnO₂(β-Bi₂O₃)/Bi₂Sn₂O₇ nanohybrids doped with Pt and Pd nanoparticles: applications in visible light photocatalysis, electrical conductivity and dye-sensitized solar cells

Abstract

Bi2O3-SnO2 nanocomposites formed at a nominal molar ratio of 3 : 1 and loaded with Pd/Pt nanoparticles synthesized by a sol gel-hydrothermal method with the aid of a template were thoroughly characterized by X-ray diffraction, TEM-EDX, N2 sorptiometry, diffuse reflectance UV-Vis, FTIR, photoluminescence and electrical conductivity. It has been shown that Pd and Pt stimulate the existence of β-Bi2O3 and SnO2, respectively together with the key component Bi2Sn2O7. The photocatalytic results indicate that Pd/β-Bi2O3-Bi2Sn2O7 revealed a remarkable performance for the degradation of methylene blue (MB) dye as compared to the Pt/SnO2-Bi2Sn2O7 and Bi2O3-SnO2 samples in both the UV and visible regions. The enhanced photocatalytic activity of the Pd/β-Bi2O3-Bi2Sn2O7 nanocomposite is primarily attributed to the broad contact between the β-Bi2O3 and Bi2Sn2O7 phases, which indicates high mesoporosity and heterojunction structures resulting in separation efficacy between photo-induced electron-hole pairs. Specifically, the photosensitive β-Bi2O3 is easily excited and released electrons to be accepted by Bi2Sn2O7 and Pd that might be deposited in the interlayer between β-Bi2O3 and Bi2Sn2O7. The degradation mechanism of MB over Pd/β-Bi2O3-Bi2Sn2O7 in the visible region showed that the dye degradation proceeds through evolution of ˙O2(-) and ˙OH radicals as evaluated using photoluminescence and free radical trapping experiments. An insight into the electrical properties including the dielectric constant and impedance of the materials indicates that Pd/β-Bi2O3-Bi2Sn2O7 has the highest conductivity based on increasing the ionic transport and defects at the β-Bi2O3/Bi2Sn2O7 heterojunction. This material displayed an improved photocurrent response of a higher power conversion efficiency, exceeding that of Pt/SnO2-Bi2Sn2O7 and SnBi3 by 50% and 250%, respectively, in dye-sensitized solar cells. Picosecond-resolved photoluminescence (PL) and polarization gated PL anisotropy measurements were combined to clarify the process of FRET from the excited Pd/β-Bi2O3-Bi2Sn2O7 to SD N719. This indicates that the latter structure can be proposed as a multifunctional candidate for use in dye-sensitized solar cells, as an electrical material and as an efficient photocatalyst based on its versatile structure.

In2O3/Bi2Sn2O7 heterostructured nanoparticles with enhanced photocatalytic activity

“…Hence, rational design of heterojunction photocatalysts with appropriate band edges has been observed to be one of the most efficient ways to reduce the electron-hole recombination rate [23][24].…”

Rapid reduction of nitroarenes photocatalyzed by an innovative Mn3O4/α-Ag2WO4 nanoparticles

“…Whereas, the bands at 1628 cm −1 and 3400 broad cm −1 are related respectively, to water molecules stretching vibrations and hydrated free O-H groups 36 www.nature.com/scientificreports/ band structures of valence band and conduction band; apart from the individual analogue. This is expected to alter the behaviors of photo-generated charge carriers as well as the excitation processes 30,31 . The shift of the OH stretching band into lower wavenumbers (3388 cm −1 ) besides its broadening is correlated to strengthening of the hydrogen bonding interaction.…”

“…Apparently, neither Ag 2 WO 4 nor Mn 3 O 4 is employed in nitroarenes photoreduction unlike metal oxides supported noble metals [27][28][29][30][31] , which use to suffer a rapid decrease in the activity due to metal aggregation and leachability in addition to the noble metal high prices that limits its usage on a large-scale.…”

“…Based on the above knowledge, there are yet no articles devoted on the combination of Mn 3 O 4 with Ag 2 WO 4 to configure their impact on the photocatalytic reduction of nitroarenes under visible light illumination. The heterojunction based on Ag 2 WO 4 /Mn 3 O 4 is expected to possess an excellent candidate capable of nullifying the photocorrosion of Ag 2 WO 4 ; based on the electron transfer from Mn 4+ /Mn 3+ and Mn 3+ /Mn 2+ moieties manipulated by structural changes 30,31 , amplify light harvesting as well as expanding the charges separation. In the present study, we have successfully utilized ultrasonication-deposition-precipitation route to fabricate Mn 3 O 4 /Ag 2 WO 4 nano-composite in the absence of any stabilizing agents with no agglomeration and high performance towards nitroarenes photo-reduction.…”

Effect of platinum doping on the structural and electrical properties of SnO2thin films

“…where [49] Accordingly, there was a slight increase in the lattice constant of S003 compared to pure SnO 2 , which indicates that some of the Pt 4C ions (with ionic radius 7.7 nm) incorporate into the Sn 4C sites of the SnO 2 (7.2 nm) lattice. [50]…”