Boosting chemoselective reduction of 4-nitrostyreneviaphotoinduced energetic electrons fromin situformed Cu nanoparticles on carbon dots

Article abstract of DOI:10.1039/d1gc00409c

Chemoselective hydrogenation of structurally diverse nitroarenes is a challenging process that often requires precious metal catalysts and proceeds in an organic solvent. Herein, a convenient and stable hybrid nanocatalyst combining carbon dots and copper nanoparticles is developed as an ideal alternative for this transformation. The as-prepared nanocatalyst achieves over 99% selectivity for the formation of 4-aminostyrene at 100% conversion of 4-nitrostyrene in an aqueous solvent under visible light irradiation. Compared with other reported catalysts, our presented catalyst shows more superior hydrogenation selectivity and stability as well as lower material cost. This high efficiency could be originated from the nanocatalyst's ability to synergistically control surface hydrogen species released from ammonia borane and energetic “hot” electrons induced by visible light irradiation for the selective reduction reaction. Compared with other reported catalysts, our presented nanocatalyst is better for the realization of energy-saving chemical processes by introducing solar energy.

Full text of DOI:10.1039/d1gc00409c

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Boosting chemoselective reduction of
4-nitrostyrene via photoinduced energetic
electrons from in situ formed Cu nanoparticles on
carbon dots†
Cite this: Green Chem., 2021, 23,
2938
Received 3rd February 2021,
Accepted 22nd March 2021
Yuqi Ren,‡a Caihong Hao,‡a Qing Chang, a Ning Li, a Jinlong Yanga,b and
DOI: 10.1039/d1gc00409c
a
rsc.li/greenchem
Shengliang Hu
*
Chemoselective hydrogenation of structurally diverse nitroarenes can also capture visible light via the localized surface plasmon
is a challenging process that often requires precious metal cata- resonance (LSPR) effect.8,9 Unfortunately, nanometer Cu
lysts and proceeds in an organic solvent. Herein, a convenient and usually suffers from poor chemical stability during catalytic
stable hybrid nanocatalyst combining carbon dots and copper processes. In this context, various substrate-supported Cu
nanoparticles is developed as an ideal alternative for this trans- nanoparticles (CuNPs),8,10–12 such as graphene-supported
formation. The as-prepared nanocatalyst achieves over 99% CuNPs,8 WO2.72-supported CuNPs,10 and Sm2Co17-supported
selectivity for the formation of 4-aminostyrene at 100% conversion CuNPs,11 have been developed to inhibit their oxidation in the
of 4-nitrostyrene in an aqueous solvent under visible light presence of molecular oxygen, and they have been applied for
irradiation. Compared with other reported catalysts, our presented chemoselective hydrogenation of aryl nitro to amine
catalyst shows more superior hydrogenation selectivity and stabi- groups.8,10,11 Nevertheless, these developed catalysts only work
lity as well as lower material cost. This high efficiency could be ori- in organic solvents, exerting huge pressure on the environ-
ginated from the nanocatalyst’s ability to synergistically control ment and cost of manufacturing.13 In contrast, water is of low
surface hydrogen species released from ammonia borane and cost and has relative abundance and ecological advantages. As
energetic “hot” electrons induced by visible light irradiation for the a solvent with many unique properties such as a large temp-
selective reduction reaction. Compared with other reported cata- erature window in which it keeps in the liquid state, high heat
lysts, our presented nanocatalyst is better for the realization of capacity, and extensive hydrogen bonding, water may be also
energy-saving chemical processes by introducing solar energy.
endowed with inherent functions to enhance the rates and
affect the selectivity of organic reactions. Besides, the supports
also possess some unique nanomaterial properties, providing
a synergistic platform for catalytic reaction.10,11 Thus, exerting
external stimuli to improve both selectivity and activity of the
as-prepared heterogeneous catalysts simultaneously is highly
desirable.
Ammonia borane (AB) and borohydrides are regarded as
safe, mild and inexpensive reagents for applications in
reduction processes of modern organic chemistry.14,15
Hydrogen species are released from AB or borohydrides to the
surface of catalysts and then are utilized to reduce nitro-aro-
matics to aromatic amines for the realization of hydrogenation
reaction under ambient conditions.16 When another reducible
functional group, e.g. vinyl group, is present in the structure of
nitro-aromatics, this hydrogenation process becomes complex
since there is competition between two reduction reactions,10
thereby often giving rise to poor selectivity.
Enhancing the selectivity and activity of catalysts is of para-
mount importance for the realization of energy-saving chemi-
cal processes.1,2 For instance, the manufacture of functiona-
lized anilines, which are pivotal intermediates for the pharma-
ceutical, polymer, agrochemical, and fine chemical
industries,1,3,4 highly depends on noble metal catalysts that
can selectively reduce aryl nitro groups without affecting other
easily reducible functionalities.3,5,6 However, these precious
metals possess the disadvantages of high cost and limited
availability. Therefore, using more Earth-abundant alternatives
to catalyze the same reaction is attracting much interest.1,7
Non-noble metal Cu nanostructures are not only cheap but
aResearch Group of New Energy Materials and Devices, North University of China,
Taiyuan 030051, P. R. China. E-mail: hsliang@yeah.net
bState Key Laboratory of New Ceramics and Fine Processing, Tsinghua University,
Beijing 100084, P. R. China
Carbon dots (CDs) are composed of carbon cores that are
surrounded by shells containing surface functional groups and
they have been found to possess excellent optical and lumine-
scence properties, photo-induced electron transfer, and elec-
†Electronic supplementary information (ESI) available: Experimental details,
sample characterization methods, the reduction of 4-NS and other supporting
results. See DOI: 10.1039/d1gc00409c
‡These authors contributed equally to this work.
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tron reservoir properties.17–22 Accordingly, CDs are emerging of both samples, revealing two different sets of diffraction
as ideal nanocatalytic platforms for the transformation of valu- peaks that correspond to cubic phases of Cu (PDF#85-1326)
able organic compounds and artificial photosynthesis under and Cu2O (PDF#78-2076), respectively. The valence states of Cu
mild operating conditions.19–21 In this contribution, we first element in samples were further characterized by X-ray photo-
utilized CDs to directly reduce Cu ions to CuNPs under hydro- electron spectroscopy (XPS). A shift difference in binding
thermal conditions, leading to in situ combination of CDs and energy was observed from both samples (Fig. 1b), indicating
CuNPs (namely CDs@CuNPs). Using the CDs@CuNPs as a the presence of Cu0 in CDs@CuNPs and Cu+ in the contrast
catalyst then catalyzes AB for selective hydrogenation of sample.12,23 All of the above results confirm that the formation
4-nitrostyrene to 4-vinylaniline in aqueous solution under of Cu is attributed to the presence of CDs.
ambient conditions. Under visible light irradiation,
The transmission electron microscopy (TEM) image of the
CDs@CuNPs exhibit significantly enhanced activity and Cu2O sample shows a large structure with micron sizes
selectivity to reduce 4-nitrostyrene to 4-aminostyrene. We have (Fig. 2a). The corresponding high-resolution TEM (HRTEM)
achieved >99% chemoselectivity from 100% conversion within image illustrates the lattice fringe of Cu2O with a spacing dis-
20 min at 298 K under one sun irradiation.
tance of 0.24 nm, which can be assigned to the interplanar
Under the same hydrothermal conditions, a control sample spacing of (111) planes of Cu2O. Differently, the TEM image of
(namely Cu2O) was also synthesized following the same pro- CDs@CuNPs depicts spheroidal shapes assembled from small
cedure and processes as that for CDs@CuNPs but without nanoparticles. By further HRTEM characterization, one can
adding CDs. Fig. 1a shows the X-ray diffraction (XRD) patterns observe the distinct hetero-nanostructure that consists of a
carbon dot with a planar spacing of 0.32 nm and a Cu nano-
particle with a planar spacing of 0.21 nm. The energy-disper-
sive X-ray spectroscopy (EDS) maps exhibit that Cu, C and O
elements are distributed uniformly in the spheroidal shapes.
This implies that numerous hybrid nanoparticles of CDs and
CuNPs constitute a large spheroidal structure.
Catalytic hydrogenation of 4-nitrostyrene (4-NS) may
achieve three typical products, i.e. 4-aminostyrene (4-AS),
4-nitroethylbenzene (4-NE) and 4-ethylbenzenamine (4-EA).2
For chemoselective hydrogenation of 4-nitrostyrene into 4-ami-
nostyrene, the vinyl group is one of the most competitive to
the formation of functional amines. Fig. 3a shows the UV-Vis
absorption spectra of three products as well as 4-NS for com-
Fig. 1 XRD patterns (a) and XPS Cu 2p spectra of samples (b).
Fig. 2 TEM and HRTEM images of Cu2O (a, b) and CDs@CuNPs (c, d), and EDS mappings of CDs@CuNPs (e).
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Fig. 3 UV-Vis absorption spectra: (a) the solution of pure 4-NS (1), 4-AS (2), 4-NE (3) and 4-EA (4); (b) the evolution of 4-NS reduction over
CDs@CuNPs with time under dark conditions; (c and d) the evolution of 4-NS reduction over CDs@CuNPs with time in the absence of EDTA-2Na (c)
and in the presence of EDTA-2Na (d) under illumination; (e and f) the evolution of 4-NS reduction over Cu2O with time under dark conditions (e)
and illumination (f).
parison. Clearly, each molecule is endowed with its own Due to the low hydrogen species release rate from AB in the
characteristic absorption peak. Thus, catalytic transformation ethanol solution, CDs@CuNPs also exhibited a low catalytic
processes of 4-NS and the products formed with time can be activity in the selective reduction of 4-NS when the aqueous
monitored using UV–Vis spectroscopy. The addition of solution was replaced with the mixed solution of water and
CDs@CuNPs to a solution of 4-NS and AB resulted in a ethanol without changing other conditions (Fig. S5†). When
gradual decrease in the 311 nm band, and simultaneous the concentration of AB was held in large excess (Fig. S6†) or
appearance of a peak centered at 273 nm (Fig. 3b) corres- AB was replaced with NaBH4 (Fig. S7†) or N2H4·H2O (Fig. S8†)
ponding to the formation of the 4-AS product. The generation without changing the amount of catalysts, CDs@CuNPs lost
of 4-AS was verified by gas chromatography-mass spectrometry their selective reduction ability or exhibited low catalytic rate
(GC-MS, Fig. S1†). The catalytic reaction was stopped in in the transformation of 4-NS into 4-AS. Similarly, different
12 min. Under visible light irradiation (the corresponding products were formed after the addition of the Cu2O sample to
spectrum shown in Fig. S2†), the characteristic peak at 273 nm a solution of 4-NS and NaBH4 (Fig. S9†). We then chose
increases slightly in absorbance (Fig. 3c), but it enhances 4-nitrophenol (4-NP) as a model molecule to further explore
remarkably with irradiation time after adding ethylenediami- the effect of hydrogen releasing rates on catalytic hydrogen-
netetraacetic acid disodium salt (EDTA-2Na) as
a hole ation. Under the same conditions, the CDs@CuNPs is much
scavenger24,25 (Fig. 3d). The transformation from 4-NS to 4-AS more active than Cu2O for the reduction of 4-NP to 4-amino-
was complete in 20 min (Table 1). Similarly, CDs@CuNPs also phenol (4-AP) in the presence of AB no matter whether irra-
showed good selectivity in the reduction of 4-nitrophenylacety- diated with visible light or not (Fig. S10†). Besides, its activity
lene under the same conditions (Fig. S3†). The control experi- and conversion efficiency in NaBH4 solution become more
ment with Cu2O added to a solution of 4-NS and AB showed superior to those in AB solution while reducing 4-NP to 4-AP
no evidence of the formation of 4-AS (Fig. 3e), but instead (Fig. S11†). According to the above results, both CDs@CuNPs
4-EA. Additionally, the product is unchanged under visible and Cu2O are all active in the reduction of –NO2 and their
light irradiation (Fig. 3f and Table 1).
activities increase with the hydrogen releasing rates. Therefore,
Catalytic hydrogenation of 4-NS could be determined by the we inferred that the selectivity of CDs@CuNPs could be
hydrogen evolution reaction of AB in an aqueous solution that ascribed to its control ability of hydrogen species released by
relies on the activity of the catalyst. First of all, it should be AB. More interestingly, light energy input is able to boost the
noted that CDs@CuNPs can’t reduce 4-NS in the absence of reduction of –NO2 in the styrene structure, while inactivating
AB whether the reaction system is irradiated or not (Fig. S4†). the –CvC group in the presence of hole scavengers.
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Table 1 Selective hydrogenation of 4-NS to 4-AS with different catalystsa
Entry
Catalyst
Reductant
Solvent
T/tb (K min−1
)
Yield (%)
Selectivity (%)
1
2
3
CDs@CuNPs
Cu2O
Cu2O@Cu
AB
AB
AB
H2O
H2O
H2O
298/20
298/20
298/20
>99
0
0
100
0
0
a Reaction conditions: 2 mg of 4-NS, 3 mg of catalyst, 2 mg of AB, 20 mL of H2O, 4 mg of EDTA-2Na, 100 mW cm−2 of light intensity. b Reaction
temperature/reaction time.
tive slope that represents an n-type semiconductor. Clearly, the
MS plot slope of CDs@CuNPs is the smallest one among the
three samples. Based on the below equation,12
Nd ¼ 2ðe0εε0Þꢀ1jdðCꢀ2Þ=dVjꢀ1
ð1Þ
where Nd, e0, ε and ε0 represent the carrier density, the elec-
tron charge, the dielectric constant and the vacuum permittiv-
ity, respectively. The carrier density of CDs@CuNPs was calcu-
lated as 12 × 1021 cm−3, which is dramatically higher than that
of Cu2O@Cu (5.1 × 1021 cm−3). When Nd is beyond 1021 cm−3
,
the collective oscillations of free conduction band (CB) elec-
trons (for n-type semiconductors) could give rise to the LSPR
effect under visible light irradiation. This confirms that the
energetic electrons can be generated from CDs@CuNPs while
being excited by visible light. Fig. S13a† shows the time-depen-
dent UV–Vis absorbance spectra for the selective reduction of
4-NS irradiated with the fixed excitation wavelength at 560
10 nm without adding the EDTA-2Na hole scavenger. The
characteristic absorption peak of 4-AS obtained using the
LSPR frequency of the CDs@CuNPs as the input light source
shows higher intensity than that from visible light irradiation
(Fig. S13b†). Particularly, the intensity of the characteristic
absorption peak increases linearly with the input energy of the
fixed excitation wavelength at 560 10 nm in the presence of
Fig. 4 (a) Adsorption amounts of 4-NS over Cu2O and CDs@CuNPs
versus time at different temperatures; (b) UV-Vis absorption spectra of
Cu2O, Cu2O@Cu and CDs@CuNPs; (c) MS plots of Cu2O, Cu2O@Cu and
CDs@CuNPs; (d) photocurrent responses of Cu2O, Cu2O@Cu and
CDs@CuNPs.
Since the first hydrogenation process is endothermic and EDTA-2Na, indicating the specific role of energetic electrons in
the rate-limiting step,3,10 the affinity of catalysts to 4-NS plays light-mediated selective reduction reactions (Fig. S13c†).
an important role in the catalytic reaction. As shown in Fig. 4a,
Besides the role of LSPR, the Schottky barrier (ϕSB) at the
the adsorption amount of 4-NS on the surface of both catalysts interface of CuNPs and CDs could help trap the transferred
is increased with shaking time at the given initial concen- energetic electrons in the CB of CDs by delaying them from
tration and temperature. After the adsorption reaches a traveling back to CuNPs.26,28 This effectively prolongs their life-
maximum value, it remains constant. More importantly, the times and fosters surface chemical reactions.26,27 Fig. 4d
adsorption reaction can speed up with an increase in reaction shows the photocurrent responses of three samples under
temperature.
visible light irradiation. Due to the presence of interfacial ϕSB,
As demonstrated previously,26,27 the interaction of LSPR the photocurrent response of CDs@CuNPs and Cu2O@Cu
with adsorbate orbitals will make energetic charge carriers does not display a rectangular shape like that of the Cu2O
inject into the adsorbate. Plasmon-generated energized car- sample. Among them, CDs@CuNPs produce the highest
riers provide not only electrons and holes but also thermal photocurrent density under the same conditions, suggesting
energy for the chemical reaction,27 so they can influence the that they possesses a superior ability to suppress the recombi-
energetics of adsorbates and enhance the net reaction rate of nation of photogenerated electron–hole pairs through a hetero-
chemical transformations. As illustrated in Fig. 4b, the absorp- geneous interface of CuNPs and CDs.
tion band at around 560 nm for CDs@CuNPs can be assigned
Particularly, the role of CDs in CDs@CuNPs is unique and
to the LSPR absorption of CuNPs.8 In contrast, the LSPR irreplaceable. For instance, we employed Cu2O@Cu as a con-
absorption at 560 nm is absent in the Cu2O sample, but it is trast catalyst to reduce 4-NS and found its poor selectivity to
observed from the nanocomposite of Cu2O and Cu (named the hydrogenation of –NO2 to –NH2 in the presence of the
Cu2O@Cu, its XRD pattern is shown in Fig. S12†). We then –CvC group under the same conditions as CDs@CuNPs
conducted Mott–Schottky (MS) plots (Fig. 4c), revealing a posi- (Table 1 and Fig. S14†). However, Cu2O@Cu exhibited higher
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activity to reduce 4-NP in contrast to the Cu2O sample facilitates more surface hydrogen species to participate in the
(Fig. S15†). Moreover, the energy level structures of the samples reduction of 4-NS to 4-AS. The EDTA-2Na scavenger not only
were analyzed using their XPS valence band spectra together suppresses the recombination of electrons and holes but also
with their MS plots (Fig. S16†). We found that the introduction impedes the occurrence of the hole-induced oxidation reac-
of CDs can elevate the CB bottom position of catalysts tion. Therefore, CDs@CuNPs offer a desired synergistic effect
(Fig. S17†). This behavior could be helpful for improving the on the surface hydrogen species released from AB and boost-
activity and selectivity in AB-initiated hydrogenation of 4-NS.
ing selective hydrogenation of –NO2 in the styrene structure
Fig. 5a illustrates the catalytic mechanism of CDs@CuNPs through energetic electrons induced by visible light
for chemoselective hydrogenation of 4-NS. There are two cases: irradiation.
the appropriate amount of AB (Case 1) and the excessive
We further performed the stability test of CDs@CuNPs in
amount of AB (Case 2). AB can be catalyzed at the surface of the reaction solution of chemoselective hydrogenation of 4-NS.
CDs@CuNPs to release the surface hydrogen species for invol- The sample was recovered by centrifugation followed by
ving the reduction reaction.16 Concomitantly, 4-NS molecules washing with ethanol and water. The CDs@CuNPs maintain
adsorb onto the unoccupied sites of the surface of their initial selectivity and show only a slight decrease in
CDs@CuNPs. The reduction of 4-NS to 4-AS with the surface activity after five catalytic cycles (Fig. 5b). The high stability
hydrogen species proceeds over the catalyst. For case 1, the also verifies that CDs are able to stabilize CuNPs during selec-
hydrogen species generated on the surface of CDs@CuNPs react tive hydrogenation of 4-NS to 4-AS. Compared with other
preferentially with –NO2 groups in the styrene structure. For reported catalysts,3,4,7,29,30 our presented catalyst shows more
case 2, the excessive hydrogen species will attack vinyl groups superior hydrogenation selectivity and stability as well as lower
simultaneously, thereby making selectivity become poor.
material cost (Table S1†). What’s more, the chemoselective
Under visible light irradiation, LSPR-generated energetic catalytic hydrogenation performance of CDs@CuNPs was
electrons with sufficient energy are transferred to the CB of almost unchanged when simulated AM 1.5G solar light
CDs and then are injected into the unpopulated electronic (100 mW cm−2) replaced visible light as a light source
orbitals of 4-NS.26 The 4-NS adsorbed on the surface of the (Fig. S18†). This indicates that taking advantage of the inex-
catalyst could be moved to a different potential energy haustible solar energy source can effectively drive CDs@CuNPs
surface.27 The forces induced on atoms in the 4-NS result in to fulfill the reactions of selective hydrogenation of nitro-
nuclear motion of atoms or vibration energy, causing the acti- arenes, reducing the pressure of energy consumption and
vation of specific chemical bonds of –NO2.27 This process carbon emission.
In conclusion, we have used CDs as reducing agents for
in situ formation of CuNPs on their surface under hydro-
thermal conditions. The obtained heterogeneous nano-
composites of CDs@CuNPs show a highly active and selective
reduction of nitrostyrene, achieving over 99% selectivity for
the formation of 4-AS at 100% conversion of 4-NS within
20 min of reaction time in the presence of AB under visible light
irradiation. The high efficiency of CDs@CuNPs is originated
from its ability to simultaneously control surface hydrogen
species released from AB and energetic electrons induced by
visible light irradiation for the selective reduction of 4-NS to
4-AS in an aqueous solution. We also found that CDs in
CDs@CuNPs not only stabilize CuNPs, but also prolong the life-
times of energetic electrons to boost the selective activation of
chemical bonds in nitrostyrene. Therefore, this work opens a
novel pathway for the rational design of ideal nanocomposite
catalysts for the realization of energy-saving chemical processes.
Conflicts of interest
The authors declare no conflicts of interest.
Acknowledgements
Fig. 5 (a) Schematic illustration of the catalytic mechanism of
This work was supported by the Specialized Research Fund for
the Sanjin Scholars Program of Shanxi Province, the Program
CDs@CuNPs for chemoselective hydrogenation of 4-NS under visible
light irradiation and (b) the cycling stability of CDs@CuNPs.
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for the Innovative Talents of Higher Education Institutions of 15 F. Fu, C. Wang, Q. Wang, A. M. Martinez-Villacorta,
Shanxi, the Key Research and Development Plan (International
Cooperation) of Shanxi Province (201903D421082), and the
Transformation of Scientific and Technological Achievements
Programs of Higher Education Institutions in Shanxi (TSTAP).
A. Escobar, H. Chong, X. Wang, S. Moya, L. Salmon,
E. Fouquet, J. Ruiz and D. Astruc, J. Am. Chem. Soc., 2018,
140, 10034–10042.
16 S. Wunder, Y. Lu, M. Albrecht and M. Ballauff, ACS Catal.,
2011, 1, 908–916.
17 C. Rosso, G. Filippini and M. Prato, ACS Catal., 2020, 10,
8090–8105.
18 H. Zhao, G. Liu, S. You, F. V. A. Camargo, M. Zavelani-
Rossi, X. Wang, C. Sun, B. Liu, Y. Zhang, G. Han,
A. Vomiero and X. Gong, Energy Environ. Sci., 2021, 14,
396–406.
Notes and references
1 R. V. Jagadeesh, A.-E. Surkus, H. Junge, M.-M. Pohl,
J. Radnik, J. Rabeah, H. Huan, V. Schünemann,
A. Brückner and M. Beller, Science, 2013, 342, 1073–1076.
2 J. Mao, W. Chen, W. Sun, Z. Chen, J. Pei, D. He, C. Lv, 19 H. Yu, R. Shi, Y. Zhao, G. I. N. Waterhouse, L.-Z. Wu,
D. Wang and Y. Li, Angew. Chem., Int. Ed., 2017, 56, 11971–
11975.
3 S. Furukawa, Y. Yoshida and T. Komatsu, ACS Catal., 2014,
4, 1441–1450.
C.-H. Tung and T. Zhang, Adv. Mater., 2016, 28, 9454–9477.
20 M. Han, S. Zhu, S. Lu, Y. Song, T. Feng, S. Tao, J. Liu and
B. Yang, Nano Today, 2018, 19, 201–218.
21 C. Hu, M. Li, J. Qiu and Y.-P. Sun, Chem. Soc. Rev., 2019, 48,
2315–2337.
4 H. Wei, X. Liu, A. Wang, L. Zhang, B. Qiao, X. Yang,
Y. Huang, S. Miao, J. Liu and T. Zhang, Nat. Commun., 22 J. Liu, Y. Liu, N. Liu, Y. Han, X. Zhang, H. Huang,
2014, 5, 5634.
Y. Lifshitz, S.-T. Lee, J. Zhong and Z. Kang, Science, 2015,
347, 970–974.
23 S. Zhang, Y. Ma, H. Zhang, X. Zhou, X. Chen and Y. Qu,
Angew. Chem., Int. Ed., 2017, 56, 8245–8249.
24 S. Hu, W. Yang, N. Li, H. Wang, J. Yang and Q. Chang,
Small, 2018, 14, 1803447.
25 F. Li, Q. Chang, N. Li, C. Xue, H. Liu, J. Yang, S. Hu and
H. Wang, Chem. Eng. J., 2020, 394, 125045.
5 L. Wang, J. Zhang, H. Wang, Y. Shao, X. Liu, Y.-Q. Wang,
J. P. Lewis and F.-S. Xiao, ACS Catal., 2016, 6, 4110–4116.
6 J. Song, Z.-F. Huang, L. Pan, K. Li, X. Zhang, L. Wang and
J.-J. Zou, Appl. Catal., B, 2018, 227, 386–408.
7 S. Chen, L.-L. Ling, S.-F. Jiang and H. Jiang, Green Chem.,
2020, 22, 5730–5741.
8 X. Guo, C. Hao, G. Jin, H.-Y. Zhu and X.-Y. Guo, Angew.
Chem., Int. Ed., 2014, 53, 1973–1977.
9 M. B. Gawande, A. Goswami, F.-X. Felpin, T. Asefa,
26 Y. Zhang, S. He, W. Guo, Y. Hu, J. Huang, J. R. Mulcahy
and W. D. Wei, Chem. Rev., 2018, 118, 2927–2954.
X. Huang, R. Silva, X. Zou, R. Zboril and R. S. Varma, 27 L. Zhou, D. F. Swearer, C. Zhang, H. Robatjazi, H. Zhao,
Chem. Rev., 2016, 116, 3722–3811.
L. Henderson, L. Dong, P. Christopher, E. A. Carter,
P. Nordlander and N. J. Halas, Science, 2018, 362,
69–72.
10 M. Shen, H. Liu, C. Yu, Z. Yin, M. Muzzio, J. Li, Z. Xi, Y. Yu
and S. Sun, J. Am. Chem. Soc., 2018, 140, 16460–16463.
11 Z. Ma, H. Liu and M. Yue, Nano Res., 2019, 12, 3085–3088.
12 F. Li, N. Li, C. Xue, H. Wang, Q. Chang, H. Liu, J. Yang and
S. Hu, Chem. Eng. J., 2020, 382, 122484.
28 Z. Zhang and J. T. Yates, Chem. Rev., 2012, 112, 5520–
5551.
29 A. Corma and P. Serna, Science, 2006, 313, 332–334.
13 X. Wei, M. Zhou, X. Zhang, X. Wang and Z. Wu, ACS Appl. 30 J. Camacho-Bunquin, M. Ferrandon, H. Sohn, D. Yang,
Mater. Interfaces, 2019, 11, 39116–39124.
14 M. Periasamy and M. Thirumalaikumar, J. Organomet.
Chem., 2000, 609, 137–151.
C. Liu, P. A. Ignacio-de Leon, F. A. Perras, M. Pruski,
P. C. Stair and M. Delferro, J. Am. Chem. Soc., 2018, 140,
3940–3951.
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