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Article

Facile Synthesis of Urchin-like Hollow Au Crystals for In Situ SERS Monitoring of Photocatalytic Reaction

by
Yuanzhao Wu
,
Mingjie Chen
,
Haohao Bai
,
Binjie Wang
,
Jiye Wang
,
Yazhou Qin
* and
Weixuan Yao
*
Key Laboratory of Drug Prevention and Control Technology of Zhejiang Province, Zhejiang Police College, 555 Binwen Road, Binjiang District, Hangzhou 310053, China
*
Authors to whom correspondence should be addressed.
Crystals 2022, 12(7), 884; https://doi.org/10.3390/cryst12070884
Submission received: 30 April 2022 / Revised: 17 June 2022 / Accepted: 19 June 2022 / Published: 22 June 2022
(This article belongs to the Section Crystalline Metals and Alloys)
Browse Figures
Versions Notes

Abstract

:
Hollow urchin-like Au nanocrystals have been widely studied due to their excellent surface plasmon resonance properties and large specific surface area, but the controllable preparation of hollow urchin-like Au nanocrystals is still a challenge. In this article, we successfully prepared hollow urchin-like Au nanocrystals using HAuCl4·3H2O and AgNO3 as precursors and ascorbic acid as the reducing agent. No surface ligands or polymer stabilizers are required in the preparation process. HAuCl4·3H2O and AgNO3 will first form AgCl cubes, then the reducing agent, ascorbic acid, will reduce the Au3+ in the solution to Au0, and Au0 will be deposited on the pre-formed AgCl cubes to form AgCl@Au nanocrystals. We characterized the morphology of the prepared Au nanocrystals by scanning electron microscopy and found that by increasing the amount of HAuCl4·3H2O in the reaction, the surface morphology of the Au nanocrystals would change from a rough spherical shape to an urchin-like shape. By further increasing the amount of the precursor HAuCl4·3H2O, urchin-like Au will convert into flake-like morphology. The AgCl in the interior was removed with ammonia water, and finally, hollow urchin-like Au crystals were formed. In addition, we used R6G molecule to explore the surface-enhanced Raman spectroscopy (SERS) enhancement effect of prepared Au crystals. The results show that the minimum detectable concentration of R6G reaches 10−8 M. Moreover, we applied hollow urchin-like Au nanocrystals as catalysts and SERS enhancing materials to detect the photocatalytic reaction of 4-NTP. We used a 785 nm laser as both the SERS light source and the catalytic light source to monitor the photocatalytic effect of the laser on 4-NTP in situ by adjusting the laser power.

1. Introduction

In recent years, metal nanocrystals have attracted great interest from researchers due to their unique surface plasmon resonance effect. Especially in the past few decades, people have conducted in-depth research on the electromagnetic properties [1,2,3], optical properties [4,5,6] and catalytic properties [7,8,9] of noble metal nanocrystals. Among them, the morphology and size of noble metal nanocrystals play a crucial role in their physical and chemical properties. Through the unremitting efforts of researchers, a large number of studies have reported on the preparation methods of noble metal nanocrystals with controllable morphology and size, including solvothermal method, electrochemical method and photochemical method. For example, Xia et al. successfully prepared Ag cubes with regular morphology and size by solvothermal method [10]. Sun et al. synthesized Pt nanocrystals with regular THH and TDP morphologies with a high index facet by electrochemical method [11]. Guillermo used femtosecond laser shaping to prepare Au nanorods with super-arrow surface plasma resonance (SPR) [12]. Various noble metal nanocrystals with regular morphology have also been prepared one after another, including low-index facet crystals [13,14,15,16,17], high-index facet crystals [18,19,20,21,22], flower-like crystals [23,24,25], chiral structure [26,27,28,29], porous structure crystals [30,31,32] and urchin-like crystals [33,34,35].
Among them, Au nanocrystals are one of the most studied noble metal nanocrystals due to their excellent chemical stability and surface plasma resonance effect. In particular, Au nanocrystals with an urchin-like structure have broad light absorption and scattering properties compared with spherical Au nanocrystals of a similar size. Urchin-like Au nanoparticle is a type of multipod Au nanocrystals with spines on the surface. By adjusting the size of urchin-like Au nanocrystals, the length of the thorn-like structure on the surface can realize the regulation of light scattering and light absorption characteristics [36]. For example, Xu et al. achieved the preparation of urchin-like Au nanocrystals with two different sizes of 150 and 25 nm by regulating the growth time of seeds, the ratio of precursors in Au/Ag seeds and the number of Au precursors used during growth. The results showed the local surface plasma resonance peak (LSPR) red-shifted with the increase in the length of the thorn-like structure [37]. Studies have shown that there are extremely strong electric fields (hot spots) in the tips and gaps of the spines, which can be used for highly sensitive surface-enhanced Raman detection of trace substances. When the substance to be tested is adsorbed to the hot spots at the tip and gap, its Raman signal can be enhanced by several orders of magnitude [38,39]. In addition, urchin-like Au nanocrystals have tunable SPR bands in the near infrared (NIR) region and dense hot spots at the tip and gap, making them very suitable for detection of biological tissues [40,41]. So far, various methods have been developed for preparing urchin-like Au nanocrystals. For example, Huang et al. prepared urchin-like Au nanocrystals by seed growth method using sodium dodecyl sulfate as a ligand [42]. Adam et al. used HAuCl4, AgNO3 and ascorbic acid to react in polyethylene glycol tert-octylphenyl ether solution at room temperature, and controlled the extent of branching of urchin-like Au nanocrystals by regulating the concentration of ascorbic acid in the reaction [43]. Recently, we adopted the seed growth method, using glutathione adsorbed on the Au seeds as the directing agent to reduce the Au ions in situ to prepare urchin-like Au nanocrystals, realizing the highly sensitive SERS detection of atropine [44]. However, the above methods often require the use of surfactants or polymers as ligands to induce the formation of urchin-like structure, which makes the surface of the prepared nanocrystals adsorb a large number of molecules that will interfere with further use. Therefore, it is necessary to develop a method without ligand to prepare urchin-like Au nanocrystals with clean surfaces. As far as we know, only a small number of studies have reported a method for preparing urchin-like Au nanocrystals without ligands [45,46,47].
In this article, we use chloroauric acid trihydrate and silver nitrate as precursors, and first form AgCl at room temperature. Then, the reducing agent ascorbic acid is added to the solution to reduce Au3+ to Au0. Au0 atoms will be deposited on the pre-formed AgCl particles and eventually form an urchin-like structure. Ammonia water was used to remove the AgCl located inside to obtain hollow sea urchin-shaped Au nanocrystals. We investigated the SERS enhancement effect of the prepared crystals with R6G as the molecule to be tested, and the lowest detection concentration reached 10−8 M. Moreover, we used hollow sea urchin-like Au crystals as bifunctional catalysts and SERS-enhancing materials and used a 785 nm laser as both the SERS light source and the catalytic light source to monitor the photocatalytic effect of the laser on 4-NTP in situ by adjusting the laser power.

2. Materials and Methods

2.1. Materials

Ascorbic acid (AA, 99.0% purity), hydrogen tetrachloroaurate (III) trihydrate (HAuCl4·3H2O, 99% purity), silver nitrate (AgNO3, 99.0% purity), Rhodamine 6G (R6G, AR, 99%), 4-nitrothiophenol (4-NTP, 80%) and ethanol (EG, 99%) were purchased from Aladdin. All the reagents were used as received directly without further purification. Deionized water with resistivity of 18.2 MΩ·cm−1 was collected from the ultrapure water system and used in all the experiments.

2.2. Preparation of Urchin-like Au Crystals

A typical procedure for synthesizing Au crystals was as follows: 100 µL of 0.5 M HAuCl4·3H2O solution and 20 mL deionized water were added to a 50 mL round-bottom flask in turn at room temperature. Then, 10 µL of 0.5 M AgNO3 solution was injected into the mixture and the mixture was stirred for 30 min to make sure of formation of AgCl nanocrystals. After that, 3.0 mL of 0.2 M ascorbic acid solution was added quickly to the above solution and the mixture was continuously stirred for 30 min. The color of the mixture turned from light yellow to dark brown, indicating the formation of the urchin-like Au crystals. After the reaction, the mixture was centrifuged at 5000 rpm for 5 min and the acquired sample was ultrasonically cleaned with deionized water and ethanol twice. Finally, a dark brown colored powder sample was obtained and dispersed in ethanol at room temperature for further characterization and use.

2.3. Characterization and SERS Measurement

The morphology and microstructure of prepared urchin-like Au crystals was characterized by scanning electron microscope (JSM-6700F, 3.0 kV, JEOL, Tokyo, Japan), transmission electron microscope (100 kV, JEM-2100f, JEOL, Tokyo, Japan), high-resolution TEM (JEM-2100f, 200 kV, JEOL, Tokyo, Japan). Raman spectral measurements were conducted with a Confocal Raman microscopy (DXR2xi, Thermo Fisher, Waltham, MA, USA). The SERS spectra of substrates were measured by Raman microscopy with the following parameters: excitation laser wavelength of 785 nm with power of 10 mW and acquisition time of 10 s. A typical SERS detection process is as follows (take R6G for example): 10 μL Au nanocrystals dispersed solution and 50 μL R6G solution (10−6 M) were added in a 1.5 mL centrifuge tube and mixed well for 10 min. After that, the resulting solution was dripped on a clean and transparent glass slide, and then measured the Raman spectra with a 50× objective lens after drying at room temperature. All the Raman spectra obtained from experiment were analyzed using OMNIC for Dispersive Raman software equipped with the equipment for de-baseline processing and the SERS measurements conditions were the same as the above procedure.

2.4. In Situ Monitoring of Photocatalytic Reactions by SERS

First, 100 μL of 0.1 mM 4-NTP and the prepared Au crystals were mixed in the reaction cell and placed in the dark for 30 min to allow 4-NTP molecules to bind through Au-S bonds on the surface of Au particles. The reaction cell was then placed under the laser for testing, and spectra were collected at 1-min intervals. Under the condition that other reaction parameters are kept the same, the 785 nm laser power is adjusted to 1 mW, 5 mW and 20 mW, respectively, to monitor the in-situ photocatalytic process.

3. Results and Discussion

The characterization results of the prepared hollow urchin-like Au nanocrystals are shown in Figure 1. Figure 1A is a scanning electron microscope (SEM) image of the obtained crystals with short thorn structures on the surface prepared when a small amount of HAuCl4 precursor (50 μL) was added. We can see that the crystals have an urchin-like structure as a whole. When the amount of the precursor HAuCl4 was increased to 500 μL, the SEM image of the prepared crystal was shown in Figure 1B. From the figure, we can see that the surface of the crystal has an obvious spike structure. Figure 1C shows the characterization results of the corresponding single-particle crystals by transmission electron microscopy (TEM). We can clearly see that the spike structures are densely distributed on its surface. High resolution transmission electron microscopy (HRTEM) was used to further observe the structure of the synthesized urchin-like Au crystals. As shown in Figure 1D, the lattice spacing is 0.24 nm, indicating that the spines of the Au nanostructures contain {111} planes. We further performed high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) characterization and energy dispersive X-ray spectroscopy (EDS) elemental mapping of the hollow sea urchin-like Au crystals (Figure 1E,F). The HAADF-STEM image of the Au crystal shows a gray area in the center and a brighter area at the edge, which can be attributed to the hollow core and the Au shell, respectively. The EDS mapping (Figure 1F,G) clearly shows that Au is distributed throughout the surface, with only a small amount of silver. EDS elemental spectroscopy further confirmed that the gold crystals were predominantly gold (95.5 wt%), with a small amount of silver (4.5 wt%).
In addition, we investigate the formation process of urchin-like Au crystals. First, during the preparation process, when the AgNO3 solution was added to the HAuCl4 solution, the color of the solution changed from yellow to white opaque, and a white precipitate was collected after centrifugation. Then, we characterized the white precipitate obtained when no reducing agent was added. Figure 2A is the SEM image of the white precipitated particles obtained by mixing the precursor HAuCl4 (10 μL, 0.5 M) with AgNO3 (10 μL, 0.5 M). We can see that the shape is cubic and the size is about 100 nm. We also performed XRD characterization to determine its composition. As shown in Figure 3, its XRD pattern shows the characteristic diffraction peaks of (111), (200), (220), (311), (222), (400) and (420), which are index to the face centered cubic (FCC) structure of AgCl [48]. In addition, we did not observe other impurity peaks, indicating that AgCl crystals are well crystallized, the samples are relatively pure and Au crystals have not yet formed. Furthermore, we can see that the intensity of the (200) peak is much higher than other peaks, which corresponds to the (100) face of the cubic AgCl crystal. The above results indicate that the Cl− in HAuCl4 and Ag+ in AgNO3 first combine to form AgCl cubes. When adding 3.0 mL of 0.2 M reducing agent ascorbic acid to the above solution, we will obtain nanocrystals as shown in Figure 2B. From the figure, we can see that its overall size is smaller than that of the AgCl cube. In this process, we infer that, due to the addition of excessive reducing agent ascorbic acid in the reaction system, AgCl cubic and Au3+ ions in the solution will be reduced. Since AgCl is reduced to Ag, the overall volume is reduced. There is still a small amount of silver in the EDS spectrum (Figure 1G) of the obtained hollow sea urchin-like gold crystals, which also indicates that AgCl is reduced to silver during the reaction. In addition, when Au3+ is reduced to Au0 atom, Au3+ will react with the newly formed Ag through a galvanic replacement reaction. As one Au3+ replaces three Ag0 atoms, thus the volume is further reduced. When we increased the amount of HAuCl4 in the reaction to 50 μL, our slurry prepared crystals as shown in Figure 2C, and we could see that it was spherical as a whole. When the amount of HAuCl4 was further increased to 100 μL, the morphology of the prepared crystals was shown in Figure 2D. Compared with Figure 2C, an obvious short spike structure appeared on the surface. When the amount of HAuCl4 was increased to 200 μL and 500 μL, more long spike structures appeared on the surface of crystal particles (Figure 2E,F). The prepared urchin-like Au crystals are obtained by removing the AgCl located in the center in a bubble bath of ammonia water to obtain hollow urchin-like Au crystals. Figures S1–S3 in Supplementary Materials is the SEM and TEM images of the crystal after removing AgCl, we can see the obvious hollow structure. In addition, the HAADF-STEM of Au crystals prepared with a small amount of Au precursors also indicates the existence of hollow structure (Figure S2). Moreover, we tried to change the concentration of ascorbic acid to explore its growth mechanism. As shown in Figure S3, when a small amount of ascorbic acid (1.0 mL) was added, part of the AgCl in the prepared particles was not reduced. When the ascorbic acid was further reduced (0.5 mL), the reaction solution was still yellow (Au3+), and the obtained particles were AgCl particles and partially reduced AgCl particles. This further confirms our above inference.
Furthermore, we used the prepared hollow urchin-like Au crystals for in situ SERS detection of the photocatalytic reduction of p-nitrothiophenol (4-NTP). We first investigated the SERS-enhanced properties of hollow urchin-like Au crystals. Using hollow urchin-like Au crystals as the SERS substrate material, the SERS test results of R6G molecules with different concentrations are shown in Figure 4, and the lowest detection concentration of R6G reaches 10−8 M. We employed the in situ SERS technique to monitor the conversion of 4-NTP to trans-DMAB using a 785 nm laser as both a photo laser and a probe source. As shown in Figure 5A, the main peaks of the SERS spectrum of 4-NTP include 1083 cm−1, 1112 cm−1, 1341 cm−1 and 1572 cm−1 [49]. Among them, 1083 cm−1 and 1572 cm−1 are vibrational peaks of the benzene ring. The peak at 1112 cm−1 is the stretching vibration peak of C–NO2, and the peak at 1341 cm−1 is the stretching vibration peak of NO2 [44]. When we used a 1 mW 785 nm laser as the catalytic light source, the time-dependent SERS spectra of 4-NTP are shown in Figure 5B. When 1 mW 785 nm laser was used as catalytic light source, the SERS spectrum of 4-NTP changed with time, as shown in Figure 5B. The spectrograms were collected at intervals of 1 minute, and we could see that with the progress of the reaction, new peaks appeared in the spectrogram at the second minute, 1145 cm−1 and 1440 cm−1. A weak peak also appeared at 1392 cm−1 when the reaction lasted for 10 min. Meanwhile, we could also see that SERS peak of 4-NTP still existed. According to previous studies 1145 cm−1, 1392 cm−1 and 1440 cm−1 can be assigned to βCH + vCN, vNN + vCN, and vNN + βCH of trans-DMAB [49]. This process showed that even at low laser power, 785 nm laser still promoted the photocatalytic reaction. When we used a 5 mW 785 nm laser as the catalytic light source, the time-dependent SERS spectra of 4-NTP are shown in Figure 5C. As the reaction proceeded, we could see that the SERS peaks of 4-NTP were basically unchanged, and the SERS peaks (1145 cm−1, 1392 cm−1 and 1440 cm−1) of trans-DMAB increased in intensity. It shows that the increase in laser power will further promote the photocatalytic reaction. When we further increased the laser power to 20 mW, the SERS spectrum of 4-NTP changed with time, as shown in Figure 5D. When we further increased the laser power to 20 mW, the SERS spectra of 4-NTP with time are shown in Figure 5D. We can see that the SERS peaks (1112 cm−1 and 1341 cm−1) of 4-NTP gradually decrease in intensity as the reaction proceeds, and basically disappear when the reaction proceeds for 10 min. The intensities of the SERS peaks (1145 cm−1, 1392 cm−1 and 1440 cm−1) of trans-DMAB increased with the reaction time and reached the highest when the reaction was carried out for 10 min. It is indicated that the photocatalytic reaction is further promoted under the laser power of 20 mW, so that 4-NTP is basically converted into trans-DMAB. The above results show that even at very weak laser power (1 mW), the photocatalytic reaction still inevitably occurs, and as the laser power increases, the photocatalytic reaction rate accelerates. When the laser power at 785 nm reaches 20 mW, it will promote the basic conversion of 4-NTP to trans-DMAB.

4. Conclusions

In conclusion, we developed a method for preparing hollow urchin-like Au crystals, and successfully prepared Au crystals with thorn-like structures of different lengths by regulating the quantity of precursors in the reaction system. Furthermore, we deduced the formation mechanism of urchin-like Au crystals. Using hollow urchin-like Au as catalysts and SERS enhancing materials, we explored the catalytic effect of 785 nm lasers with different powers on p-nitrothiophenol by in-situ SERS technology. The results show that even at 1 mW power, the 785 nm laser can still promote the photocatalytic conversion of p-nitrothiophenol to trans-4,4′-dimercaptoazobenzene on the surface of Au crystals. When the laser power is increased, the photocatalytic reaction is accelerated and the reaction rate is accelerated. When the laser power was increased to 20 mW, p-nitrothiophenol was completely converted to trans-4,4′-dimercaptoazobenzene in about 10 min.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/cryst12070884/s1. Figure S1. SEM image of the crystal after removing AgCl. Figure S2. TEM and HAADF-STEM images of gold crystals obtained when the amount of gold precursor added was 50 μL. Figure S3. SEM images of gold crystals obtained when the amount of 0.2 M ascorbic acid added was 0.5 mL (left) and 1.0 mL (right).

Author Contributions

Methodology, Y.W.; validation, W.Y., B.W. and Y.Q.; resources, W.Y., J.W. and B.W.; data curation, M.C. and H.B.; writing—original draft preparation, Y.W. and Y.Q.; writing-review and editing, B.W. and Y.Q.; supervision, Y.W.; project administration, J.W. and W.Y.; funding acquisition, W.Y. and Y.W. All authors have read and agreed to the published version of the manuscript.

Funding

This work was funded by the key research and development project of Zhejiang Province (2021C03135), National College Students Innovation and Entrepreneurship Training Program (202111483002) and Ningbo Major Special Funding of Science and Technology Innovation 2025 (2020Z010).

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Fu, N.; Sun, L.; Liang, S.; Elhadj, D.; Addad, A.; Wang, S. Enhanced thermoelectric power factor of Bi2Sr2Co2Oy thin films by incorporating Au nanoparticles. Mater. Des. 2016, 89, 791–794. [Google Scholar] [CrossRef]
  2. Yaghmaee, M.S.; Ahmadian Baghbaderani, H. Thermodynamics modeling of cohesive energy of metallic nano-structured materials. Mater. Des. 2017, 114, 521–530. [Google Scholar] [CrossRef]
  3. Ramalingam, B.; Khan, M.M.R.; Mondal, B.; Mandal, A.B.; Das, S.K. Facile synthesis of silver nanocrystals decorated magnetic-chitosan microsphere for efficient removal of dyes and microbial contaminants. ACS Sustain. Chem. Eng. 2015, 3, 2291–2302. [Google Scholar] [CrossRef]
  4. Jin, R. Atomically precise metal nanoclusters: Stable sizes and optical properties. Nanoscale 2015, 7, 1549–1565. [Google Scholar] [CrossRef]
  5. Zhu, L.; Lu, Z.; Zhang, L.; He, N. Seedless synthesis of Au nanorods with tunable plasmonic peaks beyond 1300 nm. Chin. Chem. Lett. 2022, 33, 2491–2495. [Google Scholar] [CrossRef]
  6. Qin, Y.; Wu, Y.; Wang, B.; Wang, J.; Yao, W. Facile synthesis of Ag@Au core-satellite nanowires for highly sensitive SERS detection for tropane alkaloids. J. Alloys Compd. 2021, 884, 161053. [Google Scholar] [CrossRef]
  7. Huang, Z.J.; Li, S.S.; Xu, B.L.; Yan, W.; Yuan, G.Q.; Liu, H.Y. Oxidation etching-induced post-crystallization of palladium nanosheets for efficient catalytic hydrogenation. Small 2021, 17, 2006624. [Google Scholar] [CrossRef]
  8. Yin, J.; Wang, J.; Ma, Y.; Yu, J.; Zhou, J.; Fan, Z. Recent advances in the controlled synthesis and catalytic applications of two-dimensional rhodium nanomaterials. ACS Mater. Lett. 2020, 3, 121–133. [Google Scholar] [CrossRef]
  9. Dong, J.C.; Su, M.; Briega-Martos, V.; Li, L.; Le, J.B.; Radjenovic, P.; Zhou, X.S.; Feliu, J.M.; Tian, Z.Q.; Li, J.F. Direct in situ Raman spectroscopic evidence of oxygen reduction reaction intermediates at high-index Pt (hkl) surfaces. J. Am. Chem. Soc. 2019, 142, 715–719. [Google Scholar] [CrossRef]
  10. Sun, Y.G.; Xia, Y.N. Shape-controlled synthesis of Au and silver nanocrystals. Science 2002, 298, 2176–2179. [Google Scholar] [CrossRef] [Green Version]
  11. Du, J.H.; Sheng, T.; Xiao, C.; Tian, N.; Xiao, J.; Xie, A.Y.; Liu, S.; Zhou, Z.Y.; Sun, S.G. Shape transformation of {hk0}-faceted Pt nanocrystals from a tetrahexahedron into a truncated ditetragonal prism. Chem. Commun. 2017, 53, 3236–3238. [Google Scholar] [CrossRef] [PubMed]
  12. González-Rubio, G.; Díaz-Núñez, P.; Rivera, A.; Prada, A.; Tardajos, G.; González-Izquierdo, J.; Bañares, L.; Llombart, P.; Macdowell, L.G.; Palafox, M.A.; et al. Femtosecond laser reshaping yields Au nanorods with ultranarrow surface plasmon resonances. Science 2017, 358, 640–644. [Google Scholar] [CrossRef] [PubMed]
  13. Li, Y.; Jiang, L.; Zou, Y.; Song, Z.; Jin, S. Highly reproducible SERS sensor based on self-assembled Au nanocubic monolayer film for sensitive and quantitative detection of glutathione. Appl. Surf. Sci. 2021, 540, 148381. [Google Scholar] [CrossRef]
  14. Chen, Z.; Balankura, T.; Fichthorn, K.A.; Rioux, R.M. Revisiting the polyol synthesis of silver nanostructures: Role of chloride in nanocube formation. ACS Nano 2019, 13, 1849–1860. [Google Scholar] [CrossRef] [PubMed]
  15. Swain, S.; Shenoy, B.M.; Bhol, P.; Yadav, S.; Jena, S.R.; Hegde, G.; Altaee, A.; Saxena, M.; Samal, A.K. Facet dependent catalytic activity of Pd nanocrystals for the remedy of organic Pollutant: A mechanistic study. Appl. Surf. Sci. 2021, 570, 150775. [Google Scholar] [CrossRef]
  16. Chiu, C.Y.; Li, Y.; Ruan, L.; Ye, X.; Murray, C.B.; Huang, Y. Platinum nanocrystals selectively shaped using facet-specific peptide sequences. Nat. Chem. 2011, 3, 393–399. [Google Scholar] [CrossRef] [PubMed]
  17. Zhao, M.; Chen, Z.; Shi, Y.; Hood, Z.D.; Lyu, Z.; Xie, M.; Chi, M.; Xia, Y. Kinetically Controlled synthesis of Rhodium nanocrystals with different shapes and a comparison study of their thermal and catalytic properties. J. Am. Chem. Soc. 2021, 143, 6293–6302. [Google Scholar] [CrossRef] [PubMed]
  18. Qin, Y.; Pan, W.; Yu, D.; Lu, Y.; Wu, W.; Zhou, J. Stepwise evolution of Au micro/nanocrystals from an octahedron into a truncated ditetragonal prism. Chem. Commun. 2018, 54, 3411–3414. [Google Scholar] [CrossRef] [PubMed]
  19. Huo, D.; Ding, H.; Zhou, S.; Li, J.; Tao, J.; Ma, Y.; Xia, Y. Facile synthesis of Au trisoctahedral nanocrystals with controllable sizes and dihedral angles. Nanoscale 2018, 10, 11034–11042. [Google Scholar] [CrossRef]
  20. Qin, Y.; Lu, Y.; Yu, D.; Zhou, J. Controllable synthesis of Au nanocrystals with systematic shape evolution from an octahedron to a truncated ditetragonal prism and rhombic dodecahedron. CrystEngComm 2019, 21, 5602–5609. [Google Scholar] [CrossRef]
  21. Niu, W.; Duan, Y.; Qing, Z.; Huang, H.; Lu, X. Shaping Au nanocrystals in dimethyl sulfoxide: Toward trapezohedral and bipyramidal nanocrystals enclosed by {311} facets. J. Am. Chem. Soc. 2017, 139, 5817–5826. [Google Scholar] [CrossRef] [PubMed]
  22. Reddy Satyavolu, N.S.; Peinetti, A.S.; Wang, Y.; Ali, A.S.; Lin, J.W.; Lu, Y. Silver-assisted synthesis of high-indexed palladium tetrahexahedral nanoparticles and their morphological variants. Chem. Mater. 2019, 31, 2923–2929. [Google Scholar] [CrossRef]
  23. Liu, C.; Xu, X.; Hu, W.; Yang, X.; Zhou, P.; Qiu, G.; Ye, W.; Li, Y.; Jiang, C. Synthesis of clean cabbagelike (111) faceted silver crystals for efficient surface-enhanced Raman scattering sensing of papaverine. Anal. Chem. 2018, 90, 9805–9812. [Google Scholar] [CrossRef] [PubMed]
  24. Qin, Y.; Lu, Y.; Pan, W.; Yu, D.; Zhou, J. One-pot synthesis of hollow hydrangea Au nanoparticles as a dual catalyst with SERS activity for in situ monitoring of a reduction reaction. RSC Adv. 2019, 9, 10314–10319. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. Zhang, C.Y.; Hao, R.; Zhao, B.; Fu, Y.Z.; Hao, Y.W.; Liu, Y.Q. Novel synthesis of hierarchical flower-like silver assemblies with assistance of natural organic acids for surface-enhanced Raman spectroscopy. J. Mater. Sci. 2017, 52, 11391–11401. [Google Scholar] [CrossRef]
  26. Lee, H.E.; Ahn, H.Y.; Mun, J.; Lee, Y.Y.; Kim, M.; Cho, N.H.; Chang, K.; Kim, W.S.; Rho, J.; Nam, K.T. Amino-acid-and peptide-directed synthesis of chiral plasmonic Au nanoparticles. Nature 2018, 556, 360–365. [Google Scholar] [CrossRef]
  27. Kim, H.; Im, S.W.; Cho, N.H.; Seo, D.H.; Kim, R.M.; Lim, Y.C.; Lee, H.E.; Ahn, H.Y.; Nam, K.T. γ-Glutamylcysteine and cysteinylglycin directed growth of chiral Au nanoparticles and their crystallographic. analysis. Angew. Chem. Int. Ed. 2020, 59, 2976–12983. [Google Scholar] [CrossRef]
  28. Liu, Z.; Ai, J.; Bai, T.; Fang, Y.; Ding, K.; Duan, Y.; Han, L.; Che, S. Photomagnetic-chiral anisotropy of chiral nanostructured Au films. Chem 2022, 8, 186–196. [Google Scholar] [CrossRef]
  29. González-Rubio, G.; Mosquera, J.; Kumar, V.; Pedrazo-Tardajos, A.; Llombart, P.; Solís, D.M.; Lobato, I.; Noya, E.A.; Guerrero-Martínez, A.; Taboada, J.M.; et al. Micelle-directed chiral seeded growth on anisotropic Au nanocrystals. Science 2020, 368, 1472–1477. [Google Scholar] [CrossRef]
  30. Yin, S.; Wang, Z.; Li, C.; Yu, H.; Deng, K.; Xu, Y.; Li, X.; Wang, L.; Wang, H. Mesoporous Pt@ PtM (M = Co, Ni) cage-bell nanostructures toward methanol electro-oxidation. Nanoscale Adv. 2020, 2, 1084–1089. [Google Scholar] [CrossRef] [Green Version]
  31. Odziomek, M.; Bahri, M.; Boissière, C.; Sanchez, C.; Lassalle-Kaiser, B.; Zitolo, A.; Ersen, O.; Nowak, S.; Tard, C.; Giraud, G.; et al. Aerosol synthesis of thermally stable porous noble metals and alloys by using bi-functional templates. Mater. Horiz. 2020, 7, 541–550. [Google Scholar] [CrossRef]
  32. Yin, S.; Wang, Z.; Liu, S.; Jiao, S.; Tian, W.; Xu, Y.; Li, X.; Wang, L.; Wang, H. Flexible synthesis of Au@ Pd core–shell mesoporous nanoflowers for efficient methanol oxidation. Nanoscale 2021, 13, 3208–3213. [Google Scholar] [CrossRef] [PubMed]
  33. Sun, J.; Wang, J.; Hu, W.; Wang, Y.; Chou, T.; Zhang, Q.; Zhang, B.; Yu, Z.; Yang, Y.; Ren, L.; et al. Camouflaged Au nanodendrites enable synergistic photodynamic therapy and NIR biowindow II photothermal therapy and multimodal imaging. ACS Appl. Mater. Interfaces 2021, 13, 10778–10795. [Google Scholar] [CrossRef] [PubMed]
  34. Gao, J.; Huang, L.; Zhang, Z.; Li, G. Synthesis of sea urchin-shaped Au nanocrystals by double-strand diblock oligonucleotides for surface-enhanced Raman scattering and catalytic application. Nanotechnology 2021, 32, 175501. [Google Scholar] [CrossRef]
  35. Li, J.; Lin, H.; Zhang, X.; Li, M. Seed shape-controlled, facet-selective growth of superspiky Au nanocrystals for biosensing applications. J. Mater. Chem. C 2021, 9, 8694–8704. [Google Scholar] [CrossRef]
  36. Plascencia-Villa, G.; Torrente, D.; Marucho, M.; Jose-Yacaman, M. Biodirected synthesis and nanostructural characterization of anisotropic Au nanoparticles. Langmuir 2015, 31, 3527–3536. [Google Scholar] [CrossRef]
  37. Li, Y.; Zhai, M.; Xu, H. Controllable synthesis of sea urchin-like Au nanoparticles and their optical characteristics. Appl. Surf. Sci. 2019, 498, 143864. [Google Scholar] [CrossRef]
  38. Anker, J.N.; Hall, W.P.; Lyandres, O.; Shah, N.C.; Zhao, J.; Van Duyne, R.P. Biosensing with plasmonic nanosensors. Nat. Mater. 2008, 7, 442–453. [Google Scholar] [CrossRef]
  39. Rodrigues, D.C.; Andrade, G.F.S.; Temperini, M.L.A. SERS performance of Au nanotubes obtained by sputtering onto polycarbonate track-etched membranes. Phys. Chem. Chem. Phys. 2012, 1, 1169–1176. [Google Scholar]
  40. Esenturk, E.N.; Walker, A. Surface-enhanced raman scattering spectroscopy via Au nanostars. J. Raman Spectrosc. 2010, 40, 86–91. [Google Scholar] [CrossRef]
  41. Rodriguez-Lorenzo, L.; Alvarez-Puebla, R.A.; de Abajo, F.J.G.; Liz-Marzán, L.M. Surface enhanced Raman scattering using star-shaped Au colloidal nanoparticles. J. Phys. Chem. C 2010, 114, 7336–7340. [Google Scholar] [CrossRef] [Green Version]
  42. Kuo, C.H.; Huang, M.H. Synthesis of branched Au nanocrystals by a seeding growth approach. Langmuir 2005, 21, 2012–2016. [Google Scholar] [CrossRef] [PubMed]
  43. Blanch, A.J.; Döblinger, M.; Rodríguez-Fernández, J. Simple and rapid high-yield synthesis and size sorting of multibranched hollow Au nanoparticles with highly tunable NIR plasmon resonances. Small 2015, 11, 4550–4559. [Google Scholar] [CrossRef] [PubMed]
  44. Qin, Y.; Wu, Y.; Wang, B.; Wang, J.; Zong, X.; Yao, W. Controllable preparation of sea urchin-like Au NPs as a SERS substrate for highly sensitive detection of the toxic atropine. RSC Adv. 2021, 11, 19813–19818. [Google Scholar] [CrossRef] [PubMed]
  45. Xu, F.; Cui, K.; Sun, Y.; Guo, C.; Liu, Z.; Zhang, Y.; Shi, Y.; Li, Z. Facile synthesis of urchin-like Au submicrostructures for nonenzymatic glucose sensing. Talanta 2010, 82, 1845–1852. [Google Scholar] [CrossRef]
  46. Yuan, H.; Khoury, C.G.; Hwang, H.; Wilson, C.M.; Grant, G.A.; Vo-Dinh, T. Au nanostars: Surfactant-free synthesis, 3D modelling, and two-photon photoluminescence imaging. Nanotechnology 2012, 23, 75102. [Google Scholar] [CrossRef] [Green Version]
  47. Pangdam, A.; Wongravee, K.; Nootchanat, S.; Ekgasit, S. Urchin-like Au microstructures with tunable length of nanothorns. Mater. Des. 2017, 130, 140–148. [Google Scholar] [CrossRef]
  48. Wang, J.; Qin, Y.; Shi, Q.; Wen, L.; Lei, B. Cl-Induced selective fabrication of 3D AgCl microcrystals by a one-pot synthesis method. CrystEngComm 2021, 23, 5116–5123. [Google Scholar] [CrossRef]
  49. Zhang, J.; Winget, S.A.; Wu, Y.; Su, D.; Sun, X.; Xie, Z.; Qin, D. Ag@Au Concave Cuboctahedra: A Unique Probe for Monitoring Au-Catalyzed Reduction and Oxidation Reactions by Surface-Enhanced Raman Spectroscopy. ACS Nano 2016, 10, 2607–2616. [Google Scholar] [CrossRef]
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Figure 1. Characterization of hollow sea urchin-like Au NCs. (A) SEM image of hollow Au NCs with short spines, (B) SEM images of hollow Au NCs with long spines, (C) Single particle TEM image of hollow Au NCs, (D) Corresponding HRTEM image. (E–G) EDS elemental mapping of hollow Au crystals indicating the Au and Ag elemental distribution.
Figure 1. Characterization of hollow sea urchin-like Au NCs. (A) SEM image of hollow Au NCs with short spines, (B) SEM images of hollow Au NCs with long spines, (C) Single particle TEM image of hollow Au NCs, (D) Corresponding HRTEM image. (E–G) EDS elemental mapping of hollow Au crystals indicating the Au and Ag elemental distribution.
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Figure 2. (A) SEM image of AgCl crystals without ascorbic acid. SEM images of Au crystals obtained when different amounts of HAuCl4 were added. (B) 10 μL, (C) 50 μL, (D) 100 μL, (E) 200 μL, (F) 500 μL.
Figure 2. (A) SEM image of AgCl crystals without ascorbic acid. SEM images of Au crystals obtained when different amounts of HAuCl4 were added. (B) 10 μL, (C) 50 μL, (D) 100 μL, (E) 200 μL, (F) 500 μL.
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Figure 3. XRD patterns of AgCl crystals obtained by mixing HAuCl4 and AgNO3.
Figure 3. XRD patterns of AgCl crystals obtained by mixing HAuCl4 and AgNO3.
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Figure 4. Urchin-like Au crystals were used to detect different concentrations of R6G.
Figure 4. Urchin-like Au crystals were used to detect different concentrations of R6G.
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Figure 5. (A) SERS spectrum of 4-NTP. (B–D) Time-dependent SERS spectra of 4-NTPs under the action of 785 nm laser with different powers, (B) 1 mW, (C) 5 mW, (D) 20 mW.
Figure 5. (A) SERS spectrum of 4-NTP. (B–D) Time-dependent SERS spectra of 4-NTPs under the action of 785 nm laser with different powers, (B) 1 mW, (C) 5 mW, (D) 20 mW.
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Wu, Y.; Chen, M.; Bai, H.; Wang, B.; Wang, J.; Qin, Y.; Yao, W. Facile Synthesis of Urchin-like Hollow Au Crystals for In Situ SERS Monitoring of Photocatalytic Reaction. Crystals 2022, 12, 884. https://doi.org/10.3390/cryst12070884

AMA Style

Wu Y, Chen M, Bai H, Wang B, Wang J, Qin Y, Yao W. Facile Synthesis of Urchin-like Hollow Au Crystals for In Situ SERS Monitoring of Photocatalytic Reaction. Crystals. 2022; 12(7):884. https://doi.org/10.3390/cryst12070884

Chicago/Turabian Style

Wu, Yuanzhao, Mingjie Chen, Haohao Bai, Binjie Wang, Jiye Wang, Yazhou Qin, and Weixuan Yao. 2022. "Facile Synthesis of Urchin-like Hollow Au Crystals for In Situ SERS Monitoring of Photocatalytic Reaction" Crystals 12, no. 7: 884. https://doi.org/10.3390/cryst12070884

APA Style

Wu, Y., Chen, M., Bai, H., Wang, B., Wang, J., Qin, Y., & Yao, W. (2022). Facile Synthesis of Urchin-like Hollow Au Crystals for In Situ SERS Monitoring of Photocatalytic Reaction. Crystals, 12(7), 884. https://doi.org/10.3390/cryst12070884

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