Electronic structure and photocatalytic activity of wurtzite Cu–Ga–S nanocrystals and their Zn substitution

Kandiel, Tarek A.; Anjum, Dalaver H.; Sautet, Philippe; Bahers, Tangui Le; Takanabe, Kazuhiro

doi:10.1039/c5ta01552a

Cited by 34 publications

(22 citation statements)

References 54 publications

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“…These peaks are in good agreement with the structure for the AgGa2In3S8 reference pattern (PDF 01-070-8366), indicating that they have a layered structure with hexagonal crystal packing [17]. For CuGaxIn5-xS8 nanocrystals, where x = 3, major diffraction peaks for CGIS nanocrystals are observed at 2θ values of 28.9, 56.5, and 47.8, indicating the formation of CGIS nanocrystals with zincblende structure [18], whereas at higher gallium content, i.e., where x = 4 and 5, the XRD patterns of the CGIS nanocrystals showed major diffraction peaks at 2θ values of 27.6, 29.2, 31.2, 40.4, 48.8, 52.6, and 57.8, with peak positions well-matched with the powder diffraction data reported for the wurtzite structure [19,20].…”

Section: Resultssupporting

confidence: 77%

Solvent-induced deposition of Cu–Ga–In–S nanocrystals onto a titanium dioxide surface for visible-light-driven photocatalytic hydrogen production

Kandiel

Takanabe

2016

Applied Catalysis B: Environmental

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Highlights Cu-Ga-In-S (CGIS) nanocrystals with different Ga/In ratios were readily synthesized. A unique solvent-induced deposition method was developed for loading CGIS nanocrystals onto a TiO2 surface. The CGIS/TiO2 photocatalyst showed improved visible light activity for hydrogen production. The enhanced activities are explained either by the synergistic effect between CGIS and TiO2 or by the improved dispersion and optical properties.4 Abstract:In this paper, copper-gallium-indium-sulfide (CGIS) nanocrystals with different Ga/In ratios, i.e., CuGaxIn5-xS8, where x = 0, 1, 2, 3, 4 and 5, were synthesized and investigated for visible-lightdriven hydrogen (H2) evolution from aqueous solutions that contain sulfide/sulfite ions. The synthesized CGIS nanocrystals were characterized by diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL). With 1.0 wt.% Ru as a co-catalyst, the H2 evolution rate on CuGa2In3S8(CGIS hereafter) showed the highest activity. The CGIS nanocrystals were deposited onto a TiO2 surface via a unique solvent-induced deposition method. The CGIS/TiO2 photocatalyst showed comparable activity to that obtained using bare CGIS nanocrystals when the photocatalyst amount was sufficient in the photoreactor system, suggesting that TiO2 remains intact in terms of photocatalytic activity. The quantity of CGIS nanocrystals, however, required to achieve the rate-plateau condition at saturation was much lower in the presence of TiO2. The enhanced activities at low CGIS loadings observed in the presence of TiO2 were explained by the improved dispersion of the powder suspension and optical path in the photoreactor. This TiO2 supported photocatalyst lowers the required amount of photocatalyst, which is beneficial from an economic point of view.

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Section: Resultssupporting

confidence: 77%

Solvent-induced deposition of Cu–Ga–In–S nanocrystals onto a titanium dioxide surface for visible-light-driven photocatalytic hydrogen production

Kandiel

Takanabe

2016

Applied Catalysis B: Environmental

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“…[23][24][25][26][27][28][29][30] Density functional theory (DFT) is a useful and powerful technique to obtain the relevant photophysical and optoelectronic parameters of a given photocatalyst. 31,32 In addition to structure determination, DFT calculations can lead to the simulation of several semiconductor properties such as the bandgap, the dielectric constants and band positions, with good accuracy thanks to recently developed functionals such as HSE06. 33 Furthermore, the excitonbinding energy and effective masses of electrons and holes are very important parameters, accessible from calculations, in 2 order to qualify a semiconductor as good photocatalytic material.…”

Section: Introductionmentioning

confidence: 99%

Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity

Bhunia¹,

Melissen

Parida³

et al. 2015

Chem. Mater.

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144

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Developing stable, ubiquitous and efficient water-splitting photocatalyst material that has extensive absorption in the visible-light range is desired for a sustainable solar energy-conversion device. We herein report a triazine-based carbon nitride (CN) material with different C/N ratios achieved by varying the monomer composition ratio between melamine (Mel) and 2,4,6-triaminopyrimidine (TAP). The CN material with a different C/N ratio was obtained through a two-step synthesis protocol: starting with the solution state dispersion of the monomers via hydrogen-bonding supramolecular aggregate, followed by a salt-melt high temperature polycondensation. This protocol ensures the production of a highly crystalline polytriazine imide (PTI) structure consisting of a copolymerized Mel-TAP network. The observed bandgap narrowing with an increasing TAP/Mel ratio is well simulated by density functional theory (DFT) calculations, revealing a negative shift in the valence band upon substitution of N with CH in the aromatic rings. Increasing the TAP amount could not maintain the crystalline PTI structure, consistent with DFT calculation showing the repulsion associated with additional C-H introduced in the aromatic rings. Due to the high exciton binding energy calculated by DFT for the obtained CN, the cocatalyst must be close to any portion of the material to assist the separation of excited charge carriers for an improved photocatalytic performance. The photocatalytic activity was improved by providing a dendritic tipon-like shape grown on a porous fibrous silica KCC-1 spheres, and highly dispersed Pt nanoparticles (<5 nm) were photodeposited to introduce heterojunction. As a result, the Pt/CN/KCC-1 photocatalyst exhibited an apparent quantum efficiency (AQE) as high as 22.1 ± 3% at 400 nm and the silica was also beneficial for improving photocatalytic stability. The results obtained by time-resolved transient absorption spectroscopy measurements were consistent with the improved photocatalytic activity with the slowest carrier recombination for the optimized CN photocatalyst.

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“…The suitability of the ligand assisted colloidal approach as a common method for synthesizing other 2D copper-based quaternary sulfides, i.e., CZGS, which is another important photocatalyst 15 , 50 , 51 , has also been proved. The XRD pattern in Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Single crystalline quaternary sulfide nanobelts for efficient solar-to-hydrogen conversion

Wang

Zhuang

et al. 2020

Nat Commun

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Although solar-driven water splitting on semiconductor photocatalysts is an attractive route for hydrogen generation, there is a lack of excellent photocatalysts with high visible light activity. Due to their tunable bandgaps suitable for superior visible-light absorption, copper-based quaternary sulfides have been the important candidates. Here, we first assessed the preferred facet of wurtzite Cu-Zn-In-S for photocatalytic hydrogen evolution reaction using the relevant Gibbs free energies determined by first principle calculation. We then developed a colloidal method to synthesize single crystalline wurtzite Cu-Zn-In-S nanobelts (NBs) exposing (0001) facet with the lowest reaction Gibbs energy, as well as Cu-Zn-Ga-S NBs exposing (0001) facet. The obtained single crystalline Cu-Zn-In-S and Cu-Zn-Ga-S NBs exhibit superior hydrogen production activities under visible-light irradiation, which is composition-dependent. Our protocol represents an alternative surface engineering approach to realize efficient solar-to-chemical conversion of single crystalline copper-based multinary chalcogenides.

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Electronic structure and photocatalytic activity of wurtzite Cu–Ga–S nanocrystals and their Zn substitution

Abstract: Stoichiometric and gallium-rich wurtzite Cu–Ga–S ternary nanocrystals with and without Zn substitution were synthesized and their electronic structure and photocatalytic activities were investigated.

Cited by 34 publications

References 54 publications

Solvent-induced deposition of Cu–Ga–In–S nanocrystals onto a titanium dioxide surface for visible-light-driven photocatalytic hydrogen production

Solvent-induced deposition of Cu–Ga–In–S nanocrystals onto a titanium dioxide surface for visible-light-driven photocatalytic hydrogen production

Dendritic Tip-on Polytriazine-Based Carbon Nitride Photocatalyst with High Hydrogen Evolution Activity

Single crystalline quaternary sulfide nanobelts for efficient solar-to-hydrogen conversion

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