Laser illumination-induced dramatic catalytic activity change on Au nanospheres

Ye, Zhongju; Wei, Lin; Xiao, Lehui; Wang, Jianfang

doi:10.1039/c9sc01666j

Cited by 26 publications

(47 citation statements)

References 42 publications

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“…According to the experimental measurement, the number of pixels occupied by the rectangular light spot was 2161 at the central cross section and the calculated T was 16 mm. Therefore, according to Equation (12), it could be calculated that the divergence angle of the rectangular light spot was about 23 • , which is basically consistent with the average divergence angle calculated by the theoretical Equations (1)- (3).…”

Section: Methodssupporting

confidence: 82%

“…Lasers have been widely applied in many fields, such as medical treatment [1,2], laser illumination [3,4], laser detection [5,6] and satellite communication [7,8]. However, the intensity distribution of a laser is usually in a Gaussian profile, which is always required to be converted into a flat-top profile so as to achieve the desired effect, e.g., laser welding [9,10], an optical system of exposure machine [11], laser drilling [12,13] and laser projection [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

et al. 2020

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The miniaturized and integrated microlens array (MLA) can effectively achieve the beam homogenization, compactness and miniaturization of laser systems. When the high-coherence laser beam is homogenized by means of using the MLA, interference fringes will occur in the homogenized light spot due to the periodicity of the MLA, which seriously affects the uniformity of the homogenized light spot. To solve this problem, a novel random microlens array (rMLA) structure was proposed for the purpose of achieving beam homogenization. The coherence in the homogenization process is suppressed by means of breaking the periodicity of the MLA. The homogenized light spot with a high energy utilization is then obtained accordingly. In the fabrication process, a clever method of combining chemical etching with lithography technology is performed to fabricate a honeycomb rMLA and a rectangular rMLA. The experimental results show that the energy utilization rate of the two types of the rMLAs is about 90%, and the uniformity of the homogenized light spots generated by the honeycomb rMLA and the rectangular rMLA are more than 80% and 85%, respectively. Meanwhile, fully cost-effective fabrication is possible to be realized.

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Section: Methodssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

et al. 2020

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“…5-7 and demonstrated in Figure 3C and Table 1. [28][29][30] , plasmon-induced changes of nanocatalysts itself (morphology and active site rearrangement) [31][32] and hot carriers facilitated reactant-catalyst interaction. [33][34][35] We carried out several control experiments to measure the surface temperature of Au NRs during laser irradiation ( Figure S8) and its morphology after the plasmonic photocatalysis ( Figure S9), and found negligible temperature and morphology change, thus possible contributions from photothermal effect and morphology were ruled out.…”

Section: Identification Of the Activation Energy Of Rate-limiting Stementioning

confidence: 99%

Single-Molecular Catalysis Identifying Activation Energy of the Intermediate Product and Rate-Limiting Step in Plasmonic Photocatalysis

Miao

Peng

et al. 2020

Nano Lett.

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Plasmon mediated photocatalysis provides a novel strategy for harvesting solar energy. Identification of rate determining step and its activation energy in plasmon mediated photocatalysis plays critical roles for understanding the contribution of hot carriers that facilitates rational designing catalysts with integrated high photo-chemical conversion efficiency and catalytic performance. However, it remains a challenge due to a lack of research tools with spatiotemporal resolution that capable of capturing intermediates. In this work, we used a single molecular fluorescence approach to investigate a localized surface plasmon resonance (LSPR) enhanced photocatalytic reaction with sub-turnover resolution. By introducing variable temperature as an independent parameter in plasmonic photocatalysis, the activation energies of tandem reaction steps, including intermediate generation, product generation and product dissociation, were clearly differentiated, and intermediates generation was found to be the rate-limiting step. Remarkably, the cause of plasmon enhanced catalysis performance was found to be its ability of lowering the activation energy of intermediates generation. This study gives new insight into the photo-chemical energy conversion pathways in plasmon enhanced photocatalysis and sheds light on designing high performance plasmonic catalysts. File list (2) download file view on ChemRxiv Main text-20191220.docx (2.01 MiB) download file view on ChemRxiv SI-20191220.docx (2.40 MiB)

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“…Although the former causes softening of the NP without melting being confirmed, the role of the latter in deformation needs to be further identified. The photothermal effect on elongation of suspended gold NPs into NRs caused by 532-nm laser was also reported [2]. In addition, other research showed that optical stress can be used to bend a suspending gold nanorod (NR) in water by means of an LP laser beam of 1064 nm [6].…”

Section: Introductionmentioning

confidence: 84%

“…As shown in Figure 1a, the deformation and reshaping process of gold NP/NR is divided into six stages: Stage I: A spherical NP is heated to be softened by laser beam irradiation. The optical traction stretches the NP to be an elongated NR [1,2]. Stage II and III: An elongated NR with a pronounced necking (a dumbbell with a dent at the center).…”

Section: Introductionmentioning

confidence: 99%

Plasmon-Enhanced Photothermal and Optomechanical Deformations of a Gold Nanoparticle

Liaw

Liu

et al. 2020

Nanomaterials

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Plasmon-enhanced photothermal and optomechanical effects on deforming and reshaping a gold nanoparticle (NP) are studied theoretically. A previous paper (Wang and Ding, ACS Nano 13, 32–37, 2019) has shown that a spherical gold nanoparticle (NP) irradiated by a tightly focused laser beam can be deformed into an elongated nanorod (NR) and even chopped in half (a dimer). The mechanism is supposed to be caused by photothermal heating for softening NP associated with optical traction for follow-up deformation. In this paper, our study focuses on deformation induced by Maxwell’s stress provided by a linearly polarized Gaussian beam upon the surface of a thermal-softened NP/NR. We use an elastic model to numerically calculate deformation according to optical traction and a viscoelastic model to theoretically estimate the following creep (elongation) as temperature nears the melting point. Our results indicate that a stretching traction at the two ends of the NP/NR causes elongation and a pinching traction at the middle causes a dent. Hence, a bigger NP can be elongated and then cut into two pieces (a dimer) at the dent due to the optomechanical effect. As the continuous heating process induces premelting of NPs, a quasi-liquid layer is formed first and then an outer liquid layer is induced due to reduction of surface energy, which was predicted by previous works of molecular dynamics simulation. Subsequently, we use the Young–Laplace model to investigate the surface tension effect on the following deformation. This study may provide an insight into utilizing the photothermal effect associated with optomechanical manipulation to tailor gold nanostructures.

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Laser illumination-induced dramatic catalytic activity change on Au nanospheres

Abstract: In this work, the distinct catalytic properties of a single gold nanoparticle (GNP) after symmetry breaking were disclosed at the single-particle level for the first time.

Cited by 26 publications

References 42 publications

Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

Single-Molecular Catalysis Identifying Activation Energy of the Intermediate Product and Rate-Limiting Step in Plasmonic Photocatalysis

Plasmon-Enhanced Photothermal and Optomechanical Deformations of a Gold Nanoparticle

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