Hydrothermal Synthesis of CaIn₂S₄-Reduced Graphene Oxide Nanocomposites with Increased Photocatalytic Performance

Abstract

A series of CaIn2S4-reduced graphene oxide (RGO) nanocomposites with different RGO contents were fabricated using a facile hydrothermal approach. During the hydrothermal process, the reduction of graphene oxide to RGO, in situ deposition of synthesized CaIn2S4 nanoparticles on RGO nanosheets and formation of chemical-bonding CaIn2S4-RGO nanocomposites were performed simultaneously. Under visible light irradiation, the as-prepared CaIn2S4-RGO nanocomposites showed enhanced photocatalytic performance for rhodamine B degradation and phenol oxidation. The sample with 5 wt % RGO hybridized CaIn2S4 exhibited the highest photocatalytic activity. The enhancement of photocatalytic performance may be related to the increased adsorption/reaction sites, positive shift of the valence band potential, and high separation efficiency of photogenerated charge carriers due to the electronic interaction between CaIn2S4 and RGO. We hope that this work can not only provide an in-depth study on the photocatalytic mechanism of RGO-enhanced activity, but also provide some insights for fabricating efficient and stable RGO-based photocatalysts in the potential applications of purifying polluted water resources.

Two-Dimensional CaIn2S4/g-C3N4 Heterojunction Nanocomposite with Enhanced Visible-Light Photocatalytic Activities: Interfacial Engineering and Mechanism Insight

“…It could be clearly observed that the position of the VB edge of CaIn 2 S 4 and g-C 3 N 4 are located at 1.03 and 1.71 eV, respectively, which are consistent with the previous reports. 26,38 Combined with the calculated band gaps, the conduction band (CB) edge of CaIn 2 S 4 and g-C 3 N 4 are estimated at −0.98 eV and −1.12 eV, respectively. Figure 5a shows the photocatalytic H 2 production activity of g-C 3 N 4 , CaIn 2 S 4 , and CaIn 2 S 4 /g-C 3 N 4 heterojunction nanocomposites with different contents of CaIn 2 S 4 from an aqueous solution containing 0.5 M Na 2 S and 0.5 M Na 2 SO 3 under UV light irradiation (triggered by 12 W UV-LEDs light).…”

“…26,27 The formed two-dimensional heterostructure of the nanocomposite photocatalyst could not only enhance the interfacial contact area between CaIn 2 S 4 and g-C 3 N 4 but also facilitate separation of charge carriers. As such, the CaIn 2 S 4 /g-C 3 N 4 heterojunction nanocomposites exhibited enhanced H 2 evolution and photocatalytic degradation of MO activities under visible-light irradiation in comparison to pristine g-C 3 N 4 and CaIn 2 S 4 .…”

Facile Synthesis of Novel Redox-Mediator-free Direct Z-Scheme CaIn2S4 Marigold-Flower-like/TiO2 Photocatalysts with Superior Photocatalytic Efficiency

“…The XPS results for CIS are in accord with standard reference XPS spectra, and further validate the oxidation state assignments for Ca, In, and S in the CIS marigold flowers as +2, +3, and −2, respectively. 25,26,30 From Figure 5c and Figure S5a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 composites, respectively. A peak related to the 3d 3/2 level of In 3d with a binding energy of 453.26 eV was 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21...…”

“…However, previous reports for CIS have described a mixture of nanoparticles and nanosheet-like morphologies. 25,26,30 Figure 2c shows the spherical morphology of TiO 2 , which was unchanged upon the addition of CIS (Figure 2d the 10%-CIS/TNP composite (Figure 2h), the added CIS appears to exhibit a curved sheet or tube-like structure. It is possible that, while stirring during preparation, some of the thin petals of the microspheres were exfoliated and formed curled sheets, which were subsequently rolled into tube-like structures.…”

Synthesis of g-C3N4/CaIn2S4composites with enhanced photocatalytic activity under visible light irradiation

“…Recent study found that ternary CaIn 2 S 4 , first synthesized using a facile hydrothermal method, can produce hydrogen from pure water without any cocatalysts under visible light irradiation [14]. For example, Ding synthesized the CaIn 2 S 4 Reduced Graphene Oxide Nanocomposites for efficient RhB degradation under visible light irradiation [17]. Among various strategies, the rapid separation-transfer-transformation of photo-generated charge carriers is a key issue which should be addressed [15].…”