TY - JOUR

T1 - Materials synthesis, characterization and DFT calculations of the visible-light-active perovskite-like barium bismuthate Ba1.264(4)Bi1.971(4)O4 photocatalyst

AU - Shtarev, D. S.

AU - Shtareva, A. V.

AU - Kevorkyants, R.

AU - Rudakova, A. V.

AU - Molokeev, M. S.

AU - Bakiev, T. V.

AU - Bulanin, K. M.

AU - Ryabchuk, V.K.

AU - Serpone, N.

N1 - Funding Information: The current research was kindly funded by a grant from the Russian Science Foundation (project No. 19-73-10013). R. K., A. V. R., V. K. R. and T. V. B. acknowledge financial support from Saint-Petersburg State University (Pure ID 39054581). A. V. R. thanks the Russian Foundation for Basic Research for a Grant No. 18-03-00855 that supported studies into the photoinduced hydrophilicity of the bismuthate. The authors are further grateful to the staff of the Khabarovsk Innovation and Analytical Center of the Yu. A. Kosygin Institute of Tectonics and Geophysics of the Far Eastern Branch of the Russian Academy of Sciences, and the Resource Centers of the Research Park at the Saint-Petersburg State University: (i) the Center for Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics, (ii) the Center for Physical Methods of Surface Investigation, (iii) the Center for Optical and Laser Materials Research, and the laboratories of (iv) Nanotechnology and (v) Nanophotonics for their valuable assistance in carrying out the research and in providing the needed equipment. One of us (N.S.) is grateful to Prof. Angelo Albini and the staff of the PhotoGreen Laboratory at the University of Pavia, Italy, for their continued hospitality.

PY - 2020/3/14

Y1 - 2020/3/14

N2 - A perovskite-like barium bismuthate of the BaBi 2O 4 class, Ba 1.264(4)Bi 1.971(4)O 4, has been prepared by solid-state synthesis and subsequently characterized by a number of experimental techniques (XPS, DRS, SEM, EDX and Raman spectroscopy), as well as by a DFT computational approach using the GGA Perdew-Burke-Ernzerhof (PBE) density functional to determine the energy band structure. XRD peaks were indexed to a rhombohedral cell (R3m) with parameters close to Ba 0.156Bi 0.844O 1.422 (i.e., to Ba 0.439Bi 2.374O 4), which upon Rietveld refinement gave Ba 1.264(4)Bi 1.971(4)O 4. The Bi-O bond lengths determined from this refinement (1.86 and 2.31 Å) accorded with the bond lengths estimated from Raman spectra (1.97 and 2.26 Å). DFT calculations revealed the bismuthate to display two bandgaps that correspond to lower-energy indirect (2.28 eV) and to higher-energy direct (2.36 eV) electronic transitions in good agreement with the experimental bandgaps of 2.26 eV and 2.43 eV, respectively, from Tauc plots of DRS spectra. Relative to the indirect bandgap energy of 2.26 eV, the energies of the valence band and of the conduction band were, respectively, +1.14 eV and -1.12 eV. The photoactivity of Ba 1.264(4)Bi 1.971(4)O 4 was examined toward the photoreduction of the greenhouse gas CO 2 in aqueous media photoelectrochemically yielding alcohols and alkanes, while in the gas phase in an infrared cell reactor the products were carbon monoxide and alkanes.

AB - A perovskite-like barium bismuthate of the BaBi 2O 4 class, Ba 1.264(4)Bi 1.971(4)O 4, has been prepared by solid-state synthesis and subsequently characterized by a number of experimental techniques (XPS, DRS, SEM, EDX and Raman spectroscopy), as well as by a DFT computational approach using the GGA Perdew-Burke-Ernzerhof (PBE) density functional to determine the energy band structure. XRD peaks were indexed to a rhombohedral cell (R3m) with parameters close to Ba 0.156Bi 0.844O 1.422 (i.e., to Ba 0.439Bi 2.374O 4), which upon Rietveld refinement gave Ba 1.264(4)Bi 1.971(4)O 4. The Bi-O bond lengths determined from this refinement (1.86 and 2.31 Å) accorded with the bond lengths estimated from Raman spectra (1.97 and 2.26 Å). DFT calculations revealed the bismuthate to display two bandgaps that correspond to lower-energy indirect (2.28 eV) and to higher-energy direct (2.36 eV) electronic transitions in good agreement with the experimental bandgaps of 2.26 eV and 2.43 eV, respectively, from Tauc plots of DRS spectra. Relative to the indirect bandgap energy of 2.26 eV, the energies of the valence band and of the conduction band were, respectively, +1.14 eV and -1.12 eV. The photoactivity of Ba 1.264(4)Bi 1.971(4)O 4 was examined toward the photoreduction of the greenhouse gas CO 2 in aqueous media photoelectrochemically yielding alcohols and alkanes, while in the gas phase in an infrared cell reactor the products were carbon monoxide and alkanes.

UR - http://www.scopus.com/inward/record.url?scp=85081724365&partnerID=8YFLogxK

U2 - 10.1039/C9TC06457E

DO - 10.1039/C9TC06457E

M3 - Article

VL - 8

SP - 3509

EP - 3519

JO - Journal of Materials Chemistry C

JF - Journal of Materials Chemistry C

SN - 2050-7526

IS - 10

ER -