Oxides of p-block metals (e.g., indium oxide) and semimetals (e.g., antimony oxide) are of broad practical interest as transparent conductors and light absorbers for solar photoconversion due to the tunability of their electronic conductivity and optical absorption. Comparatively, these oxides have found limited applications in solar-to-hydrogen photocatalysis primarily due to their high electronegativity, which impedes electron transfer for converting protons into molecular hydrogen. We have shown recently that inserting s-block metal cations into p-block oxides is effective at lowering electronegativities while affording further control of band gaps. Here, we explain the origins of this dual tunability by demonstrating the mediator role of s-block metal cations in modulating orbital hybridization while not contributing to frontier electronic states. From this result, we carry out a comprehensive computational study of 109 ternary oxides of s- and p-block metal elements as candidate photocatalysts for solar hydrogen generation. We downselect the most desirable materials using band gaps and band edges obtained from Hubbard-corrected density-functional theory with Hubbard parameters computed entirely from first principles, evaluate the stability of these oxides in aqueous conditions, and characterize experimentally four of the remaining materials, synthesized with high phase uniformity, to assess the accuracy of computational predictions. We thus propose seven oxide semiconductors, including CsIn3O5, Sr2In2O5, and KSbO2 which, to the extent of our literature review, have not been previously considered as water-splitting photocatalysts.
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Porous silaphosphorene, silaarsenene and silaantimonene: a sweet marriage of Si and P/As/Sb
Inspired by the recent experimental realization of pnictogen–silicon analogues of benzene and great interest in silicene, phosphorene and their heavier counterparts, herein we designed three planar porous 2D nanomaterials, namely porous silaphosphorene (pSiP), silaarsenene (pSiAs) and silaantimonene (pSiSb), and systematically investigated their stability, and electronic and optical properties, as well as their potential as photocatalysts for water splitting. Porous silaphosphorene, silaarsenene and silaantimonene monolayers are all thermodynamically, dynamically and thermally stable, and the aromaticity in each six-membered Si 3 P 3 /Si 3 As 3 /Si 3 Sb 3 ring plays an important role in their enhanced stability. They are all semiconductors with direct band gaps of 1.93, 1.57 and 0.95 eV (HSE06) and have comparable carrier mobility to MoS 2 . Their good stability and exceptional electronic and optical properties make them promising candidates for applications in solar cells and other optoelectronics fields. Moreover, the suitable band edge alignments of pSiP and pSiAs monolayers endow them with potential applications as photocatalysts for water splitting.
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- Award ID(s):
- 1736093
- NSF-PAR ID:
- 10076510
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 6
- Issue:
- 8
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 3738 to 3746
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C7TA10466A
