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
. 2020 Mar 19;11(1):1443.
doi: 10.1038/s41467-020-15262-4.

Two-dimensional gersiloxenes with tunable bandgap for photocatalytic H2 evolution and CO2 photoreduction to CO

Fulai Zhao  1 , Yiyu Feng  2   3 , Yu Wang  1 , Xin Zhang  1 , Xuejing Liang  1 , Zhen Li  1 , Fei Zhang  1 , Tuo Wang  4   5 , Jinlong Gong  4   5 , Wei Feng  6   7   8
Affiliations

Two-dimensional gersiloxenes with tunable bandgap for photocatalytic H2 evolution and CO2 photoreduction to CO

Fulai Zhao et al. Nat Commun. .

Abstract

The discovery of graphene and graphene-like two-dimensional materials has brought fresh vitality to the field of photocatalysis. Bandgap engineering has always been an effective way to make semiconductors more suitable for specific applications such as photocatalysis and optoelectronics. Achieving control over the bandgap helps to improve the light absorption capacity of the semiconductor materials, thereby improving the photocatalytic performance. This work reports two-dimensional -H/-OH terminal-substituted siligenes (gersiloxenes) with tunable bandgap. All gersiloxenes are direct-gap semiconductors and have wide range of light absorption and suitable band positions for light driven water reduction into H2, and CO2 reduction to CO under mild conditions. The gersiloxene with the best performance can provide a maximum CO production of 6.91 mmol g-1 h-1, and a high apparent quantum efficiency (AQE) of 5.95% at 420 nm. This work may open up new insights into the discovery, research and application of new two-dimensional materials in photocatalysis.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Crystal structures of CaGe2−2xSi2x and gersiloxenes.
a Schematic illustration of topotactic deintercalation of CaGe2−2xSi2x to gersiloxenes (GeH)1-x(SiOH)x (x < 0.5) or (GeH)1-xSix(OH)0.5Hx−0.5 (x ≥ 0.5) (Ca, blue; Ge, green; H, white; O, red; Si, yellow). b XRD patterns of the topotactic deintercalation products gersiloxenes with varying x (x = 0.1, 0.3, 0.5, 0.7, 0.9), GeH and Si6H3(OH)3. XRD, X-ray diffraction. Source data are provided as a Source Data file.
Fig. 2
Fig. 2. Morphology and structural characterization of gersiloxenes.
a–e Low-magnification TEM images, f–j HRTEM micrograph, and k–o electron diffraction patterns of gersiloxenes sheets. a, f, k, x = 0.1; b, g, l, x = 0.3; c, h, m, x = 0.5; d, i, n, x = 0.7; e, j, o, x = 0.9. TEM transmission electron microscopy, HRTEM high-resolution transmission electron microscopy.
Fig. 3
Fig. 3. Thickness characterization of gersiloxenes.
AFM images and corresponding height profiles of gersiloxenes nanosheets. a x = 0.1. b x = 0.3. c x = 0.5. d x = 0.7. e x = 0.9. AFM atomic force microscope. Source data are provided as a Source Data file.
Fig. 4
Fig. 4. Chemical structural characterization of gersiloxenes.
a FTIR and b Raman spectra of gersiloxenes with different x values, GeH and Si6H3(OH)3. c–f XPS spectra of gersiloxenes (x = 0.1, 0.3, 0.5, 0.7, 0.9), GeH and Si6H3(OH)3. c XPS survey spectra. High-resolution XPS spectra of d Ge3d e Si2p, and f O1s. Oads represents the adsorbed O at vacancy sites. FTIR Fourier transform infrared, XPS X-ray photoelectron spectroscopy. Source data are provided as a Source Data file.
Fig. 5
Fig. 5. Optical properties and energy band structure of gersiloxenes.
a UV–vis diffuse reflectance spectra and b Tauc plots of gersiloxenes (x = 0.1, 0.3, 0.5, 0.7, 0.9), GeH and Si6H3(OH)3. c The optical images of GeH, Si6H3(OH)3, and gersiloxenes with x = 0.1, 0.3, 0.5, 0.7, 0.9. d Energy band structure of gersiloxenes with different x values and GeH and Si6H3(OH)3 for CO2 reduction to CO and H2 evolution. VB valence band, CB conduction band. Source data are provided as a Source Data file.
Fig. 6
Fig. 6. Photocatalytic performance and electrochemical characterization.
a, b Time-dependent photocatalytic hydrogen evolution (a) and HERs (b) of gersiloxenes with x = 0.1−0.9, GeH and Si6H3(OH)3. c Photostability for H2 production of the gersiloxene with x = 0.5 (HGeSiOH). d, e Time-dependent photocatalytic CO evolution (d) and COERs (e) of gersiloxenes with x = 0.1−0.9, GeH and Si6H3(OH)3. f Time-dependent photocatalytic CO evolution for 10 h. g–i PL spectra (g), EIS Nyquist plots (h) and transient photocurrent responses (300 W xenon lamp) (i) of gersiloxenes with x = 0.1−0.9, GeH and Si6H3(OH)3. HERs, H2 evolution rates. COERs CO evolution rates, PL photoluminescence, EIS electrochemical impedance spectroscopy. Source data are provided as a Source Data file.
Fig. 7
Fig. 7. The DFT calculations on adsorption energies.
a, b Optimized geometric structures and binding energies for H2O (a) and CO2 (b) adsorption on HGeSiOH, Si6H3(OH)3, and GeH monolayers.
See this image and copyright information in PMC

References

    1. Luo B, Liu G, Wang L. Recent advances in 2D materials for photocatalysis. Nanoscale. 2016;8:6904–6920. doi: 10.1039/C6NR00546B. - DOI - PubMed
    1. Ong WJ, Tan LL, Ng YH, Yong ST, Chai SP. Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesis and environmental remediation: are we a step closer to achieving sustainability? Chem. Rev. 2016;116:7159–7329. doi: 10.1021/acs.chemrev.6b00075. - DOI - PubMed
    1. Li Y, Li YL, Sa B, Ahuja R. Review of two-dimensional materials for photocatalytic water splitting from a theoretical perspective. Catal. Sci. Technol. 2017;7:545–559. doi: 10.1039/C6CY02178F. - DOI
    1. Putri LK, Ong WJ, Chang WS, Chai SP. Heteroatom doped graphene in photocatalysis: a review. Appl. Surf. Sci. 2015;358:2–14. doi: 10.1016/j.apsusc.2015.08.177. - DOI
    1. Sun Z, Martinez A, Wang F. Optical modulators with 2D layered materials. Nat. Photonics. 2016;10:227–238. doi: 10.1038/nphoton.2016.15. - DOI