Ultrathin MoSe2 three-dimensional nanospheres as high carriers transmission channel and full spectrum harvester toward excellent photocatalytic and photoelectrochemical performance
Graphical abstract
Ultrathin MoSe2 three-dimensional nanospheres show excellent photocatalytic and photoelectrochemical performance.
Introduction
New energy materials are those that convert renewable energy into electricity. Among these renewable energy sources, hydrogen energy is an ideal energy source. Hydrogen is rich in energy and can be converted from solar energy, bioenergy, chemical energy and et al. Moreover, hydrogen energy has high energy density and green pollution free, and is expected to be widely used in new energy vehicles and personal electronic equipment[1]. There are many ways to obtain hydrogen. Photocatalysis is an efficiency approach. Solar energy is the most ideal source of hydrogen energy, and photocatalysts can convert solar energy to hydrogen energy. After the photocatalyst absorbs solar energy, it excites electron-hole pairs, which can reduce hydrogen ions into hydrogen. This transformation is green and pollution-free, and it does not consume other energy sources[[2], [3], [4]]. So much of the research on hydrogen energy materials is now focused on the development of highly efficient photocatalysts.
The earliest and most widely used photocatalyst was TiO2. TiO2 has many advantages, such as high photocatalytic activity and chemical stability, large crust content, no pollution and no toxicity[[5], [6], [7], [8]]. However, the disadvantages of TiO2 are also obvious: the large band gap (3.0–3.2 eV) result in no absorption of visible light and the internal resistance is high so that carrier transport is difficult[[9], [10], [11], [12], [13], [14], [15]]. Therefore, the hydrogen production efficiency of TiO2 is not high, and it is more suitable for photocatalytic degradation. In response to these circumstances, many narrow bandgap semiconductors have also been studied for photocatalytic hydrogen production[16]. A lot of recent studies are metal sulfides. Metal sulfides have two advantages over metal oxides. One is that the band gap is generally narrow, so that the visible light absorption efficiency is high, and the internal resistance is small result in high carrier mobility. Second, many metal sulfides have a two-dimensional structure and a large specific surface area, which is suitable for use as a catalytic reaction[[17], [18], [19], [20]]. We also did a lot of metal sulfides for photocatalysis research in the early stage[[21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31]]. Metal selenide also has two major advantages of metal sulfides. Otherwise, as the metalloid character of selenium is weaker than that of sulfur, the metal selenide has weaker ionic bond which causes narrower band gap and higher absorbance of visible light. Moreover, the carriers’ mobility of metal selenide will also be much higher than that of metal sulfide due to the narrower band gap which can lead to better performance. Among them, MoSe2 is a two-dimensional material with a band gap of only 1.7 eV, which can absorb ultraviolet light and visible light in the whole band and has good photoelectrochemical performance[[32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47]]. However, the existing chemically synthesized MoSe2 two-dimensional nanosheets are generally thicker, reaching 6–10 molecular layers, resulting in a low specific surface area[[48], [49], [50], [51], [52]]. If a thinner MoSe2 nanosheet can be obtained, its photoelectrochemical performance can be further improved.
We synthesized the ultrathin MoSe2 nanospheres by a solvothermal method. This MoSe2 nanosphere is actually constructed by some pleated ultrathin MoSe2 two-dimensional nanosheets, and the microscopic appearance is like a lot of small balls gathered together. Compared with ordinary hydrothermally synthesized flower-like MoSe2 two-dimensional nanosheets, this MoSe2 nanosphere has a thickness of only 2–3 molecular layers, which is much lower than the thickness of 6–8 molecular layers of ordinary MoSe2 nanosheets, so it has a large specific surface area. Its photocatalytic activity is 17 times than ordinary MoSe2 nanosheets, and the enhancement of photocurrent is twice. The results confirmed that the ultrathin MoSe2 nanospheres have excellent photocatalytic and photoelectrochemical properties and are suitable for photocatalytic hydrogen production.
Section snippets
Synthesis of samples
- 1)
Preparation of MoSe2 nanoflowers (MSF). MoSe2 nanoplates were prepared by a simple hydrothermal progress. First, 2 mmol Na2MoO4·H2O were dissolved in 30 mL deionized water and the mixed solution was marked as A solution. Then 4 mmol Se powder and 8 mmol NaBH4 were dispersed in 30 mL deionized water. The solution was heated to 80 °C and continuously stirred until the Se powder was completely dissolved. The solution contained Se and NaBH4 was marked as solution B. Secondly, solution A and B were
Structure and morphology
The XRD spectra of the two MoSe2 samples are shown in Fig. 2. The four main diffraction peaks can be distinguished on the two MoSe2 spectra. The positions of the four diffraction peaks correspond to the standard pattern of hexagonal MoSe2 (JCPDS No. 29–0914). The four peaks correspond to (002), (100), (103), and (110) peaks, respectively[35,47]. Otherwise, there are two low peaks at 26.6 and 65.6° can be identified as (004) and (200) peaks. It is worth noting that although the peak positions
Conclusion
MoSe2 ultrathin nanospheres with three-dimensional network structure (MSS) were prepared by improved solvothermal method. These MoSe2 nanospheres are only 10 nm in size and actually composed of ultra-thin MoSe2 nanosheets with a thickness of only 2–3 molecular layers. Compared with the MoSe2 nanosheets (6–8 molecular layer thicknesses) of the three-dimensional flower structure (MSF) prepared by ordinary hydrothermal method, the MSS are thinner resulting in higher specific surface area of 5
Acknowledgements
This work was supported by Chinese National Natural Science Foundation (No. 51602086, 51702073, 61602142 and 61072015), Zhejiang Provincial Natural Science Foundation of China (No. Y20B030030).
References (61)
- et al.
TiO2 photocatalysis and related surface phenomena
Surf Sci Rep
(2008) - et al.
Photocatalytic study of a novel crystal facets sensitive heterojunction between Sb8O11Cl2 and anatase TiO2 with different exposed facets
Dyes Pigments
(2019) - et al.
Enhanced photocatalytic activities of three-dimensional graphene-based aerogel embedding TiO2 nanoparticles and loading MoS2 nanosheets as Co-catalyst
Int J Hydrogen Energy
(2014) - et al.
Highly sensitive and selective ammonia gas sensors based on PbS quantum dots/TiO2 nanotube arrays at room temperature
Sens Actuators B Chem
(2016) - et al.
Synthesis and photocatalytic property of V2O5@TiO2 core-shell microspheres towards gaseous benzene
Catal Today
(2019) - et al.
Excellent photoelectrochemical activity of Bi2S3 nanorod/TiO2 nanoplate composites with dominant {001} facets
J Solid State Chem
(2020) - et al.
Controllable fabrication of CuO nanostructure by hydrothermal method and its properties
Appl Surf Sci
(2014) - et al.
Enhanced visible-light photocatalytic hydrogen evolution activity of Er3+:Y3Al5O12/PdS-ZnS by conduction band co-catalysts (MoO2, MoS2 and MoSe2)
Int J Hydrogen Energy
(2016) - et al.
Curved surface TiO2 nanodrums coupled with MoS2 as heterojunction photocatalysts with enhancing photocatalytic activity
Mater Lett
(2018) - et al.
A study of constructing heterojunction between two-dimensional transition metal sulfides (MoS2 and WS2) and (101), (001) faces of TiO2
Appl Surf Sci
(2018)
Novel 3D/2D heterojunction photocatalysts constructed by three-dimensional In2S3 dandelions and ultrathin hexagonal SnS2 nanosheets with excellent photocatalytic and photoelectrochemical activities
Appl Surf Sci
MnS coupled with ultrathin MoS2 nanolayers as heterojunction photocatalyst for high photocatalytic and photoelectrochemical activities
J Alloy Comp
SnS2 nanosheets coupled with 2D ultrathin MoS2 nanolayers as face-to-face 2D/2D heterojunction photocatalysts with excellent photocatalytic and photoelectrochemical activities
J Alloy Comp
Crystal face regulating MoS2/TiO2(001) heterostructure for high photocatalytic activity
J Alloy Comp
Constructing two-dimension MoS2/Bi2WO6 core-shell heterostructure as carriers transfer channel for enhancing photocatalytic activity
Mater Res Bull
Anatase TiO2 nanosheets with coexposed {101} and {001} facets coupled with ultrathin SnS2 nanosheets as a face-to-face n-p-n dual heterojunction photocatalyst for enhancing photocatalytic activity
Appl Surf Sci
Construction of network-like and flower-like 2H-MoSe2 nanostructures coupled with porous g-C3N4 for noble-metal-free photocatalytic H-2 evolution under visible light
Appl Catal B Environ
MoSe2 nanosheets perpendicularly grown on graphene with Mo-C bonding for sodium-ion capacitors
Nano Energy
Synthesis of nitrogen-doped MoSe2 nanosheets with enhanced electrocatalytic activity for hydrogen evolution reaction
Int J Hydrogen Energy
Boosting electrocatalytic activity of ultrathin MoSe2/C composites for hydrogen evolution via a surfactant assisted hydrothermal method
Int J Hydrogen Energy
A novel co-electrodeposited Co/MoSe2/reduced graphene oxide nanocomposite as electrocatalyst for hydrogen evolution
Int J Hydrogen Energy
TiO2 nanoparticles modified with 2D MoSe2 for enhanced photocatalytic activity on hydrogen evolution
Int J Hydrogen Energy
Fabrication of nanostructured CuO films by electrodeposition and their photocatalytic properties
Appl Surf Sci
Hydrogen production by molecular photocatalysis
Chem Rev
Semiconductor-based photocatalytic hydrogen generation
Chem Rev
Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting
Chem Soc Rev
Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting
Chem Soc Rev
Composite titanium dioxide nanomaterials
Chem Rev
Understanding TiO2 photocatalysis: mechanisms and materials
Chem Rev
Upconversion-P25-graphene composite as an advanced sunlight driven photocatalytic hybrid material
J Mater Chem
Cited by (19)
A novel Ni<inf>0.85</inf>Se/MoSSe heterojunction demonstrated omnipotent boosting catalytic ability in photocatalysis, photoelectrochemistry and electrocatalysis
2023, International Journal of Hydrogen EnergyStudy on the behavior of single oxygen bubble regulated by salt concentration in photoelectrochemical water splitting
2023, International Journal of Hydrogen EnergyPhotoelectrocatalytic nitrogen fixation with V<inf>o</inf>-BiOBr/TiO<inf>2</inf> heterostructured photoelectrode as photocatalyst
2022, International Journal of Hydrogen EnergyCitation Excerpt :Among them, Rct/2 represents the arc radius in high frequency region. The smaller the radius of arc, the lower the Rct value, implying the stronger electron transfer ability and the more favorable for the photoelectric reaction [52]. Compared with the BiOBr/TiO2, the electrochemical polarization resistance of the Vo-BiOBr/TiO2 is further reduced.
Photoelectrochemical degradation of Methylene blue from solution using BiOBr/Bi<inf>2</inf>S<inf>3</inf>/TiO<inf>2</inf>/GO photoanode
2022, Environmental Nanotechnology, Monitoring and ManagementCitation Excerpt :These include instances such as platinum cathode (Shao et al., 2020), stainless steel (Olvera-Rodríguez et al., 2019), and graphite (Liu et al., 2019). Due to their conductivity and effective electron transfer, anodes such as FTO (Zhang et al., 2018) and ITO (Zhang et al., 2020) were also employed. Photocatalysts were stabilized on the anodes through various procedures such as deep coating (Xia et al., 2018), hydrothermal (Han and Jia, 2016), chemical deposition (Shao et al., 2020), and spin coating (Sharma et al., 2019).