Journal of Chemistry
Volume 2020 (2020), Article ID 4150439, 7 pages
https://doi.org/10.1155/2020/4150439

Research Article

Facile Fabrication of SrTiO₃@MoS₂ Composite Nanofibers for Excellent Photodetector Application

Jinghong Li,¹ Lun Zhang,¹ Di Wang,² Ran Wang,¹ Xiujuan Liu,³ and Jingxin Zhou¹

¹Hebei Key Laboratory of Applied Chemistry, Heavy Metal Deep-Remediation in Water and Resource Reuse Key Lab of Hebei Province, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
²School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
³The First Hospital of Qinhuangdao City, Qinhuangdao 066000, China

Correspondence should be addressed to Jingxin Zhou; zhoujingxin@ysu.edu.cn

Received 31 May 2020; Accepted 29 June 2020; Published 23 July 2020

Academic Editor: Peizhi Guo

Copyright © 2020 Jinghong Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Molybdenum disulfide (MoS₂), as a kind of transition metal dichalcogenide, has been widely studied for its excellent compatibility with most of inorganic nanomaterials. Nevertheless, its microscale and agglomeration limit the performance severely. Therefore, the special structure of V-MoS₂ has drawn a lot of interest, which can not only reduce the size of MoS₂ nanosheets but also improve the valence electron structure of the materials. In this work, SrTiO₃@MoS₂ composite nanofibers were synthesized by the simple electrospinning and hydrothermal method, and it was applied as a novel material for photodetector. SEM, TEM, EDX, XRD, I-T curves, and EIS analysis were used to study the structure and properties of the prepared SrTiO₃@MoS₂ composite nanofibers. Simulating under sunlight at a potential of 1.23 V, the prepared composite materials exhibited a superior photoelectric performance of photocurrent density of 21.4 μA and a resistance of 2.3 Ω. These results indicate that the composite of SrTiO₃ nanofiber adhered with V-MoS₂ has a stable composite structure, good electrical conductivity, and photoelectric sensitivity and is a suitable material for photodetectors. This work provides new ideas for the preparation of self-assembled materials and their application in photodetectors.

1. Introduction

As we all know, water pollution, greenhouse effect, and fumes are hazardous to human beings, but few people notice that potential light pollution is also threatening our health [1–4]. Light is everywhere in our life; in fact, proper sunlight is useful for our health. However, excessive light may damage our eyesight, affect our emotions, and even induce cancer [5]. The light pollution mainly originated from assimilation lighting and massive use of architectural glass, particularly in the developed region. To solve this problem, photodetector has been widely studied as optoelectronic devices [6–8].

As a member of semiconductors, transition metal dichalcogenides (TMDCs) have shown perfect properties of its special band structure, fairly physical character, and superconductive performance [9, 10]. Within all kinds of materials of TMDCs, molybdenum disulfide (MoS₂) has attracted more and more attention due to its special structure, excellent compatibility with abundant nanoscale materials, and attractive price [11]. Therefore, MoS₂ has been used in many fields such as nano-electronic devices and optoelectronics. However, the performance of MoS₂ was limited by the lamellae stacking and the lack of active sites [12]. Recently, vertical MoS₂ (V-MoS₂) has been reported frequently in the field of photoelectricity [13]. The photoelectric performance of MoS₂ nanosheets has been improved by building a V-MoS₂ structure at the nanoscale and changing MoS₂ from a multilayer structure to a single-layer structure. Moreover, high-quality V-MoS₂ structure has a stable reproducible optoelectronic performance and is easy to fabricate. In addition, V-MoS₂ with a single-layer structure can form Mo-O bonds, which can further improve the sensitivity of the photodetector [14–16]. However, many efforts have been made to construct the V-MoS₂ structure, but most of them are still unsatisfactory for their poor performance and instability.

In this work, porous SrTiO₃ nanofibers embedded with MoS₂ nanosheets were constructed through electrospinning and hydrothermal method, which showed a V-MoS₂ structure [17–20]. The porous nanofibers can provide a stable substrate for delamination of MoS₂ to form a vertical monolayer structure. The prepared MoS₂-based material exhibited a sensitive optoelectronic performance through current density curves and Nyquist EIS plots characterization [21–23].

2. Materials and Methods

2.1. Materials

PVP (molecular weight = 1 300 000), thioacetamide (C₂H₅NS), tetrabutyl titanate (TBOT; C₁₆H₃₆O₄Ti), acetic acid (C₂H₄O₂), 2-methoxyethanol (C₃H₈O₂), strontium acetate (C₄H₆O₄Sr), sodium molybdate (Na₂MoH₄O₆), thioacetamide (C₂H₅NS), Pluronic F127, and hexadecyl trimethylammonium bromide (CTAB) were purchased from Aladdin Reagent Co, Ltd. All chemical reagents were of analytical grade (AR) and used without any further purification. The ultrapure water used throughout the experiments was extracted from a Milli-Q Millipore All Filter system (Millipore Co, Bedford, MA, USA).

2.2. Synthesis of Porous SrTiO3 Nanofibers

In brief, tetrabutyl titanate (TBOT) and strontium acetate were dissolved in 10 mL acetic acid at a mass ratio of 1.6 : 1. The mixture was vigorous stirred for 15 min until the solution transformed to transparent, and it was named solution A. Then, PVP, Pluronic F127, and CTAB were put into 6 mL 2-methoxyethanol at a mass ratio of 1 : 0.5 : 0.7 with vigorous stirring for 15 min, which has been deeply explored in previous work to ensure the proper ratio of these reagents [17]. When the mixture became transparent viscous liquid, solution A was dropped to the liquid slowly and stirred overnight. Next, the mixture was put into syringe and applied a 15 kV electric voltage at the distance of 20 cm. The ejected rate was set 0.5 ml h–1 to obtain the nanofiber membrane. Then, the prepared membrane was under pyroprocessing at 700°C for 3 h at a ramp rate of 2°C min⁻¹ to obtain the porous SrTiO₃ nanofibers.

2.3. Synthesis of SrTiO3@MoS2 2D Structure

Typically, C₂H₅NS and Na₂MoO₄·2H₂O with a mass ratio of 3 : 5 were dissolved in 15 mL ultrapure water. Then, 150 mg porous SrTiO₃ nanofibers were put into the solution. The mixed solution was then shifted to a 50 mL hydrothermal reactor and heated at 220°C for 24 h. Ultimately, the SrTiO₃@MoS₂ 2D structure was obtained through filtration separation and vacuum drying [24].

2.4. Photo(electro)chemical Measurements

8 mg SrTiO₃@MoS₂ sample and 1 mg acetylene black were transferred to a 25 mL beaker with 10 mL absolute alcohol, and then, 10 μL PTFE was dropped into the mixture with vigorous stirring. The mixed solution was ultrasonic treated for about 30 min and shaken well at last 2 min. After that, the beaker was put into a vacuum drying oven to evaporate the alcohol for 3 h and then transferred the sediment to the nickel foam. Finally, put the nickel foam into a vacuum oven at 100°C overnight and obtain the working electrodes. The photo (electro) chemical test was performed using a CHI660 electrochemical workstation with a standard three-electrode system with a graphene rod, an Ag/AgCl electrode, and nickel foam, respectively. All the measurements were tested in 1 M KOH aqueous solution under simulated solar light, which was provided by a 300 W Xe lamp. The change in the current density curve with time was tested at a potential of 1.23 V under light on/off condition [25]. The electrochemical impedance spectroscopy (EIS) tests were measured in a frequency range from 100 kHz to 0.1 Hz with an amplitude of 5 mV at η = −0.24 V [26–30].

2.5. Characterizations

X-ray diffraction (XRD) analyses of the as-prepared samples were investigated with an X-ray diffractometer (SmartLab, Rigaku, Akishima, Japan). The morphologies of prepared samples were obtained by using transmission electron microscopy (TEM) (HT7700, Hitachi High Technologies Corporation, Ibaraki, Japan) and field-emission scanning electron microscopy (SEM, S-4800II, Hitachi, Japan). Elemental map results were investigated with an Oxford Link-ISIS X-ray EDXS microanalyzer at 200 kV with SEM. All the ultrapure water used in the experiment was purified in a Milli-Q Millipore All Filter system (Millipore Co, Bedford, MA, USA).

3. Results and Discussion

3.1. Characterization of SrTiO3@MoS₂

The morphologies of as-prepared materials were obtained by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Figure 1(a) shows the SEM image of electrospun nanofibers before calcined, which mainly consisted of PVP, F127, and other ions. The diameter of nanofibers is approximately 1–3 μm and evenly distributed with a network structure. Figure 1(b) shows the image of nanofibers after being calcined at 700°C, and the surface of fibers becomes rough and shows many pores. It can be clearly observed that the diameter of fiber reduced to about 300 nm with 10–20 nm aperture gap uniform distributes on the surface. This special morphology is mainly caused by the synergistic effect of F127 and CTAB, which has been studied systematically in the earlier works. This special structure can greatly increase the surface area of SrTiO₃ NFs and provide suitable sites for loading MoS₂ [31–36]. In addition, the pores in the nanofibers can magnify the contact area between electrodes and electrolytes and optimize the structure of valence electron transmission. Figure 1(c) exhibits the result of SrTiO₃@MoS₂ composite nanofibers. It can be found that the triangular MoS₂ nanosheets firmly embed in the aperture gap of SrTiO₃ nanofibers to form a V-MoS₂ structure. TEM is carried out to further explore the structure of MoS₂ on SrTiO₃@MoS₂ hybrids, as shown in Figures 1(d)–1(f). From Figure 1(d), the diameter of as-spun nanofibers is about 200 nm, which corresponds to the SEM images. As shown in Figure 1(e), it can be observed that the calcined nanofibers are highly porous due to the different electron penetrability of various positions [37–46]. Figure 1(f) shows the composite nanofibers of SrTiO₃@MoS₂, and it can be clearly seen that the MoS₂ nanosheets and porous nanofibers combine tightly. Furthermore, the sample was under ultrasonic treatment for about 15 min before TEM operation, and the MoS₂ nanosheets were still adhered in the nanofibers. This phenomenon can convincingly demonstrate the stability of SrTiO₃@MoS₂ composite nanomaterials. The mesoporous structure in NFs provided an excellent adhesion environment to form the V-MoS₂ structure [47].

(a)

(b)

(c)

(d)

(e)

(f)

Figure 1: SEM images of (a) nanofibers before calcination, (b) porous SrTiO₃ NFs, and (c) SrTiO₃@MoS₂ composite nanofibers. TEM images of (d) nanofibers before calcination, (e) porous SrTiO₃ NFs, and (f) SrTiO₃@MoS₂ composite nanofibers.

The elemental map is one of the most commonly used techniques to observe the morphology of elements distribution. The SEM mapping of bare SrTiO₃ nanofibers and SrTiO₃@MoS₂ hybrids is shown in Figure 2. Figures 2(a)–2(d) illustrate that the elemental map of SrTiO₃ nanofibers includes Ti, Sr, and O elements. The distribution of elements matches well with the shape of nanofibers, which indicate that the porous SrTiO₃ nanofibers have been successfully prepared. Figures 2(e)–2(j) show the presence of Ti, Sr, O, Mo, and S elements on the surface of SrTiO₃@MoS₂ hybrids, proving that the MoS₂ nanosheets have been successfully adhere to the nanofibers.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)

Figure 2: SEM image of (a) porous SrTiO₃ nanofibers with (b–d) Ti/S/Sr elemental mapping and SEM image of (e) SrTiO₃@MoS₂ composite nanofibers with (f–j) Mo/S/Ti/S/Sr/O elemental mapping and (k) EDX images of SrTiO₃@MoS₂ composite nanofibers.

The crystallographic structure of the prepared materials is shown in Figure 3, illustrated by the XRD profiles. The porous SrTiO₃ nanofibers and pure MoS₂ are precisely indexed to the JCPDS 35-0734 and JCPDS 37-1492, respectively. For 2D SrTiO₃@MoS₂ composite nanofibers, the XRD peaks of SrTiO₃ appeared at 23°, 32°, 40°, 47°, 52°, 58°, 68°, and 77° can be assigned to the (100), (110), (111), (200), (210), (211), (220), and (310) planes, respectively. Nevertheless, the peaks of MoS₂ are very weak or deviated in the composite XRD patterns. The V-MoS₂ delaminated in the porous nanofibers may be due to the crystalline form changed. Interestingly, we can see some heteropeaks in the composite XRD patterns, and we discovered that the heteropeaks can fit well with the elemental sulfur. Thus, we inferred that not all the thioacetamide transferred to the MoS₂, a small amount of thioacetamide transferred to elemental S and adhered to the nanofibers, and causes some heteropeaks.

Figure 3: XRD patterns of pure MoS₂ nanosheets, porous SrTiO₃ nanofibers, and SrTiO₃@MoS₂ composite nanofibers.

In order to illustrate the high photoelectric conversion capacity of the SrTiO₃@MoS₂ composite nanofibers, the mechanism illustration is shown in Figure 4. Under simulate sunlight illumination, the porous SrTiO₃ nanofibers produce photogenerated electrons, and the holes were left in the nanofibers. For the pure SrTiO₃, the electrons and holes will recombine quickly and decrease the photoelectric performance immensely. However, after composing the V-MoS₂, the conduction band position of SrTiO₃ is much higher than MoS₂. The photogenerated electrons will transfer to MoS₂ and restrain the recombine of electrons and holes, which make the electrons more mobile and promote the photoelectric performance. Therefore, the V-MoS₂ structure can enlarge the surface area of materials and increase the active sites. In addition, the particular structure can retard the recombination of electrons and holes and then enhance the prolong of photoelectrons.

Figure 4: Schematic diagram of the photoelectric conversion mechanism of SrTiO₃@MoS₂ composite nanofibers.

3.2. Optoelectronic Performance Test

Photocurrents and the electrochemical impedance spectroscopy (EIS) were used to explore the photoelectric conversion sensitivity and electronic transmission rate of the as-prepared samples. Figure 5(a) shows the I-T curves tested in the condition of the on-off cycle simulated sunlight for the pure SrTiO₃ nanofibers and SrTiO₃@MoS₂ heterostructure. The result of SrTiO₃@MoS₂ indicates the photocurrent density is 21.4 μA, which is nearly twice higher than the pure SrTiO₃ nanofibers (10.1 μA). These results can prove that the adhering of MoS₂ improves the conductivity of materials and promotes the electron transfer rate. In addition, the V-MoS₂ nanosheets can increase the surface area of nanofibers and improve the photosensitivity and the separation of photo-induced carriers. It is also worth noting that photocurrent curves show a regular rectangle shape, indicating the stability of composite materials. The EIS results in Figure 5(b) were applied to confirm the conductivity of the prepared composite. Moreover, the Rct of SrTiO₃@MoS₂ is lower than that of porous SrTiO₃ nanofibers, indicating that the V-MoS₂ on the nanofibers can accelerate the interfacial transfer and separation of charge carriers and then improve the optoelectronic performance. The use of MoS₂ to improve the performance of materials can be included in two reasons: first, the MoS₂ improves the electronic orbital structure of the SrTiO₃ and prolongs the life of photoelectrons. Then, constructing the structure of V-MoS₂ enlarges the surface area of materials, which means a larger contact area between electrodes and electrolytes.

(a)

(b)

Figure 5: (a) The current density curves as a function of the time for SrTiO₃ and SrTiO₃@MoS₂ at 1.23 V in 1 M KOH electrolyte; (b) Nyquist plots of samples at –0.24 V versus RHE measured from EIS in the frequency range from 100 kHz to 0.1 Hz.

4. Conclusions

In summary, new SrTiO₃@MoS₂ composite materials were successfully synthesized. The structure and morphologies of the prepared composite were studied by SEM, TEM, EDX, XRD, I-T curves, and EIS analysis. The large surface area of the obtained SrTiO₃ NFs can provide suitable sites for loading MoS₂. Under simulate sunlight at a potential of 1.23 V, the prepared composite materials exhibited a superior photoelectric performance of photocurrent density of 21.4 μA and a resistance of 2.3 Ω. This study provides new clues for the preparation of MoS₂-based composite materials and is widely used in the field of photodetector.

Data Availability

The experimental data used to support the findings of this study are included in the manuscript. The other data are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that there are no conflicts of interest.

Acknowledgments

The authors greatly appreciate the financial supports of National Natural Science Foundation of China (no. 21872119), Qinhuangdao Science and Technology Support Project (no. 201602A112), Science and Technology Support Project of Department of Health of Hebei Province (no. 20171246), and Project of Human Resources and Social Security Department of Hebei Province (no. A2017002075).

References

S. Shi, Z. Sun, and Y. H. Hu, “Synthesis, stabilization and applications of 2-dimensional 1T metallic MoS₂,” Journal of Materials Chemistry A, vol. 6, no. 47, pp. 23932–23977, 2018.

J. Kou, Y. Liu, Y. Zhu, and J. Zhai, “Progress in piezotronics of transition-metal dichalcogenides,” Journal of Physics D: Applied Physics, vol. 51, no. 49, p. 493002, 2018.

Y. Fang, Y. Ge, C. Wang, and H. Zhang, “Mid-infrared photonics using 2D materials: status and challenges,” Laser and Photonics Reviews, vol. 14, no. 1, Article ID 1900098, 2020.

R. Hany, M. Cremona, and K. Strassel, “Recent advances with optical upconverters made from all-organic and hybrid materials,” Science and Technology of Advanced Materials, vol. 20, no. 1, pp. 497–510, 2019.

B. Rahmati, I. Hajzadeh, R. Karimzadeh, and S. M. Mohseni, “Facile, scalable and transfer free vertical-MoS2 nanostructures grown on Au/SiO2 patterned electrode for photodetector application,” Applied Surface Science, vol. 455, pp. 876–882, 2018.

S. Ni, F. Guo, D. Wang et al., “Optimal Sr-Doped Free TiO₂@SrTiO₃ heterostructured nanowire arrays for high-efficiency self-powered photoelectrochemical UV photodetector applications,” Crystals, vol. 9, no. 3, p. 134, 2018.

X. Lu, P. Jiang, and X. Bao, “Phonon-enhanced photothermoelectric effect in SrTiO₃ ultra-broadband photodetector,” Nature Communications, vol. 10, no. 1, p. 138, 2019.

W. Yang, Y. Zhang, Y. Zhang, W. Deng, and X. Fang, “Transparent Schottky photodiode based on AgNi NWs/SrTiO₃ contact with an ultrafast photoresponse to short-wavelength blue light and UV-shielding effect,” Advanced Functional, Materials, vol. 29, no. 46, Article ID 1905923, 2019.

X. Cui, Y. Wang, G. Jiang et al., “A photonic crystal-based CdS-Au-WO₃ heterostructure for efficient visible-light photocatalytic hydrogen and oxygen evolution,” RSC Advances, vol. 4, no. 30, pp. 15689–15694, 2014.

S. Zhou, Y. Liu, J. Li et al., “Facile in situ synthesis of graphitic carbon nitride (g-C₃N₄)-N-TiO₂ heterojunction as an efficient photocatalyst for the selective photoreduction of CO₂ to CO,” Applied Catalysis B: Environmental, vol. 159, pp. 20–29, 2014.

X. Cui, Y. Wang, G. Jiang et al., “The encapsulation of CdS in carbon nanotubes for stable and efficient photocatalysis,” Journal of Materials Chemistry, vol. 2, no. 48, pp. 20939–20946, 2014.

X. Cui, G. Jiang, M. Zhu et al., “TiO₂/CdS composite hollow spheres with controlled synthesis of platinum on the internal wall for the efficient hydrogen evolution,” International Journal of Hydrogen Energy, vol. 38, no. 22, pp. 9065–9073, 2013.

J. Xiong, J. Li, J. Shi et al., “Metallic 1T-MoS₂ nanosheets in-situ entrenched on N, P, S-codoped hierarchical carbon microflower as an efficient and robust electro-catalyst for hydrogen evolution,” Applied Catalysis B: Environmental, vol. 243, pp. 614–620, 2019.

J. Liu, L. Zhang, N. Li, Q. Tian, J. Zhou, and Y. Sun, “Synthesis of MoS₂/SrTiO₃ composite materials for enhanced photocatalytic activity under UV irradiation,” Journal of Materials Chemistry A, vol. 3, no. 2, pp. 706–712, 2015.

L. Wang, X. Liu, J. Luo et al., “Self-optimization of the active site of molybdenum disulfide by an irreversible phase transition during photocatalytic hydrogen evolution,” Angewandte Chemie International Edition, vol. 56, no. 26, pp. 7610–7614, 2017.

H. Zhou, Y. Liu, L. Zhang, H. Li, H. Liu, and W. Li, “Transition metal-doped amorphous molybdenum sulfide/graphene ternary cocatalysts for excellent photocatalytic hydrogen evolution: synergistic effect of transition metal and graphene,” Journal of Colloid and Interface Science, vol. 533, no. 3, pp. 287–296, 2019.

Y. Fu, X. Chen, X. Mou, Z. Ren, X. Li, and G. Han, “A dual-color luminescent localized drug delivery system with ratiometric-monitored doxorubicin release functionalities,” ACS Biomaterials Science & Engineering, vol. 2, no. 4, pp. 652–661, 2016.

H. Bai, Z. Liu, and D. D. Sun, “Facile fabrication of TiO₂/SrTiO₃ composite nanofibers by electrospinning for high efficient H₂ generation,” Journal of the American Ceramic Society, vol. 96, no. 3, pp. 942–949, 2013.

Z. Cao, C. Wang, and J. Chen, “Synthesis and photocatalytic property of p–n junction YMnO₃/SrTiO₃ composites,” Materials Research Express, vol. 5, no. 11, Article ID 115512, 2018.

D. Hou, X. Hu, W. Ho, P. Hu, and Y. Huang, “Facile fabrication of porous Cr-doped SrTiO3 nanotubes by electrospinning and their enhanced visible-light-driven photocatalytic properties,” Journal of Materials Chemistry A, vol. 3, no. 7, pp. 3935–3943, 2015.

C. Grandclément, A. Piram, M.-E. Petit et al., “Biological removal and fate assessment of diclofenac using Bacillus subtilis and brevibacillus laterosporus strains and ecotoxicological effects of diclofenac and 4′-Hydroxy-diclofenac,” Journal of Chemistry, vol. 2020, Article ID 9789420, 12 pages, 2020.

J. Zhao, P. Zhang, J. Fan, J. Hu, and G. Shao, “Constructing 2D layered MoS₂ nanosheets-modified Z-scheme TiO₂/WO₃ nanofibers ternary nanojunction with enhanced photocatalytic activity,” Applied Surface Science, vol. 430, pp. 466–474, 2018.

H. Hou, F. Gao, L. Wang et al., “Superior thoroughly mesoporous ternary hybrid photocatalysts of TiO₂/WO₃/g-C₃N₄ nanofibers for visible-light-driven hydrogen evolution,” Journal of Materials Chemistry A, vol. 4, no. 17, pp. 6276–6281, 2016.

L. Zhang, J. Yin, K. Wei et al., “Fabrication of hierarchical SrTiO₃@MoS₂ heterostructure nanofibers as efficient and low-cost electrocatalysts for hydrogen-evolution reactions,” Nanotechnology, vol. 31, no. 20, Article ID 205604, 2020.

X. Yue, S. Yi, R. Wang, Z. Zhang, and S. Qiu, “Well-controlled SrTiO3@Mo2C core-shell nanofiber photocatalyst: boosted photo-generated charge carriers transportation and enhanced catalytic performance for water reduction,” Nano Energy, vol. 47, pp. 463–473, 2018.

Y. Li, N. Luo, Z. Tian et al., “H₂O₂-free photo-Fenton degradation of organic pollutants on thermally exfoliated g-C₃N₄,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 586, Article ID 124190, 2020.

M. Yang, R. Liu, H. Chen, H. Li, and P. Guo, “Synthesis of self-assembled nickel cobaltite microspheres and their electrocapacitive behavior in aqueous electrolytes,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 587, Article ID 124329, 2020.

J. Sun, M. Yang, Y. Gong, H. Li, and P. Guo, “Synthesis of Pd₃Pb colloidal nanocrystal assembly and their electrocatalytic activity toward ethanol oxidation,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 586, Article ID 124224, 2020.

X. Yang, Z. Tian, Y. Chen, H. Huang, and J. Hu, “One-pot calcination preparation of graphene/g-C₃N₄-Co photocatalysts with enhanced visible light photocatalytic activity,” International Journal of Hydrogen Energy, vol. 45, no. 23, pp. 12889–12902, 2020.

L. Ge, M. Zhang, R. Wang et al., “Fabrication of CS/GA/RGO/Pd composite hydrogels for highly efficient catalytic reduction of organic pollutants,” RSC Advances, vol. 10, no. 26, pp. 15091–15097, 2020.

J. Yin, F. Zhan, T. Jiao et al., “Facile preparation of self-assembled MXene@Au@CdS nanocomposite with enhanced photocatalytic hydrogen production activity,” Science China Materials, vol. 63, 2020.

J. Yin, Q. Liu, J. Zhou et al., “Self-assembled functional components-doped conductive polypyrrole composite hydrogels with enhanced electrochemical performances,” RSC Advances, vol. 10, no. 18, pp. 10546–10551, 2020.

R. Wang, X. Yan, B. Ge et al., “Facile preparation of self-assembled black phosphorus-dye composite films for chemical gas sensors and surface-enhanced Raman scattering performances,” ACS Sustainable Chemistry & Engineering, vol. 8, no. 11, pp. 4521–4536, 2020.

K. Ma, R. Wang, Y. Rao, W. Zhao, S. Liu, and T. Jiao, “Langmuir-Blodgett films of two chiral perylene bisimide-based molecules: aggregation and supramolecular chirality,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 591, Article ID 124563, 2020.

Y. Feng, J. Yin, S. Liu, Y. Wang, B. Li, and T. Jiao, “Facile synthesis of Ag/Pd nanoparticle-loaded poly(ethylene imine) composite hydrogels with highly efficient catalytic reduction of 4-nitrophenol,” ACS Omega, vol. 5, no. 7, pp. 3725–3733, 2020.

Y. He, R. Wang, C. Sun et al., “Facile synthesis of self-assembled NiFe layered double hydroxide-based azobenzene composite films with photoisomerization and chemical gas sensor performances,” ACS Omega, vol. 5, no. 7, pp. 3689–3698, 2020.

J. Song, C. Yuan, T. Jiao et al., “Multifunctional antimicrobial biometallohydrogels based on amino acid coordinated self-assembly,” Small, vol. 16, no. 8, Article ID 1907309, 2020.

C. Cai, R. Wang, S. Liu et al., “Synthesis of self-assembled phytic acid-mxene nanocomposites via a facile hydrothermal approach with elevated dye adsorption capacities,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 589, Article ID 124468, 2020.

Y. Xu, R. Wang, Y. Zheng et al., “Facile preparation of self-assembled Ni/Co phosphates composite spheres with highly efficient her electrocatalytic performances,” Applied Surface Science, vol. 509, Article ID 145383, 2020.

R. Geng, J. Yin, J. Zhou et al., “In situ construction of Ag/TiO₂/g-C₃N₄ heterojunction nanocomposite based on hierarchical co-assembly with sustainable hydrogen evolution,” Nanomaterials, vol. 10, no. 1, p. 1, 2020.

F. Zhan, J. Yin, J. Zhou et al., “Facile preparation and highly efficient catalytic performances of Pd-Cu bimetallic catalyst synthesized via Seed-mediated method,” Nanomaterials, vol. 10, no. 1, p. 6, 2020.

Y. Feng, R. Wang, J. Yin et al., “Facile synthesis of Cu₂O nanoparticle-loaded carbon nanotubes composite catalysts for reduction of 4-Nitrophenol,” Current Nanoscience, vol. 16, no. 4, pp. 611–618, 2020.

J. Zhao, J. Yin, J. Zhong et al., “Facile preparation of a self-assembled Artemia cyst shell-TiO₂-MoS₂ porous composite structure with highly efficient catalytic reduction of nitro compounds for wastewater treatment,” Nanotechnology, vol. 31, no. 8, p. 85603, 2020.

Y. Meng, J. Yin, T. Jiao et al., “Self-assembled copper/cobalt-containing polypyrrole hydrogels for highly efficient ORR electrocatalysts,” Journal of Molecular Liquids, vol. 298, Article ID 112010, 2020.

J. Yin, F. Zhan, T. Jiao et al., “Highly efficient catalytic performances of nitro compounds via hierarchical PdNPs-loaded MXene/polymer nanocomposites synthesized through electrospinning strategy for wastewater treatment,” Chinese Chemical Letters, vol. 31, no. 4, pp. 992–995, 2020.

K. Ma, R. Wang, T. Jiao et al., “Preparation and aggregate state regulation of co-assembly graphene oxide-porphyrin composite Langmuir films via surface-modified graphene oxide sheets,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 584, Article ID 124023, 2020.

X. Xu, Y. Liu, W. Fu et al., “Poly(N-isopropylacrylamide)-based thermoresponsive composite hydrogels for biomedical applications,” Polymers, vol. 12, no. 3, p. 580, 2020.