Surfactant Removal for Colloidal Nanoparticles from Solution Synthesis: The Effect on Catalytic Performance

Li, Dongguo; Wang, Chao; Tripković, Dušan; Sun, Shouheng; Marković, Nenad M.; Stamenković, Vojislav R.

doi:10.1021/cs300219j

Cited by 448 publications

(442 citation statements)

References 28 publications

(41 reference statements)

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“…This complex behaviour derives from the creation of a metal-ligand interphase, where electronic and steric factors lead to a sensitive modification of the local environment [30]. The extent of these effects is a function of the coverage degree, the composition, the spatial arrangement and the specific From a catalytic point of view, the presence of capping agents is considered to have an adverse impact on the performances of MNPs, mainly because of the hindered access of reactants to catalyst surface [24,25]. Different strategies such as thermal annealing [26], solvent washing [27] and UV-ozone (UVO) irradiation [28], have been utilized to remove the ligand from particle surface.…”

Section: Introductionmentioning

confidence: 99%

Untangling the Role of the Capping Agent in Nanocatalysis: Recent Advances and Perspectives

et al. 2016

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Capping agents (organic ligands, polymers, surfactants, etc.) are a basic component in the synthesis of metal nanoparticles with controlled size and well-defined shape. However, their influence on the performances of nanoparticle-based catalysts is multifaceted and controversial. Indeed, capping agent can act as a "poison", limiting the accessibility of active sites, as well as a "promoter", producing improved yields and unpredicted selectivity control. These effects can be ascribed to the creation of a metal-ligand interphase, whose unique properties are responsible for the catalytic behavior. Therefore, understanding the structure of this interphase is of prime interest for the optimization of tailored nanocatalyst design. This review provides an overview of the interfacial key features affecting the catalytic performances and details a selection of related literature examples. Furthermore, we highlight critical points necessary for the design of highly selective and active catalysts with surface and interphase control.

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Section: Introductionmentioning

confidence: 99%

Untangling the Role of the Capping Agent in Nanocatalysis: Recent Advances and Perspectives

et al. 2016

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“…In the presence of excess surface ligands (essentially necessary during the wet-chemical synthesis), ligands can form a densely packed self-assembled monolayer (SAM) in the thickness of 0.5-3 nm by maximizing van der Waals interactions of alkyl chains [18]. The surface ligands are demonstrated to be detrimental to the catalytic activity in many examples [20][21][22][23][24][25][26][27]. The formation of SAMs is often considered to block the surface accessibility, leading to a decrease in the accessibility of catalytic sites [20,23], although there are many reported examples showing that surface ligands do not depress catalytic activity of metal NPs [28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Engineering Surface Ligands of Noble Metal Nanocatalysts in Tuning the Product Selectivity

Liu

Duay

et al. 2017

Catalysts

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Nanosized noble metal catalysts supported on high-surface-area support are of great importance for numerous industrial chemical processes to mediate reaction pathways in heterogeneous catalysis. Control of surface area and surface energy of nanocatalysts is a key to achieving high activity and selectivity for desired products. In the past decade, new synthetic methodologies for noble metal nanocatalysts with well-defined nanostructures have been developed. Wet-chemical preparation of noble metal nanocatalysts usually involves the utilization of specific surfactants that can bind the surface of nanocatalysts as ligands to control the nanostructures and prevent the coalescence of nanocatalysts. Surface ligands that form a densely packed self-assembled monolayer offer a facile solution to tune the surface energy of nanocatalysts, and, therefore, the selectivity of products. In this minireview, we highlight the recent advances in understanding the role of surface ligands in control over the product selectivity in a multi-product reaction using noble metal nanocatalysts. The review is outlined according to the three possible roles of surface ligands, including steric effect, orientation effect and surface charge state, in varying the adsorption/binding of reactants/transition states.

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“…Acetic acid (HOAc) was employed in attempts to remove this surfactant from the particles, as had been done with Pt nanoparticles. 26 The In NPs were sonicated in 10% HOAc in IPA, for 60 min before being centrifuged and resuspended in the same solvent mixture. These 10% HOAc-suspended particles were slightly larger (13.2 ± 7.1 nm diameters) than the untreated set, due to acidcatalyzed Ostwald ripening, leading to the growth of larger particles at the expense of the smallest particles.…”

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confidence: 99%

Enhanced Carbon Dioxide Reduction Activity on Indium-Based Nanoparticles

White

Bocarsly

2016

J. Electrochem. Soc.

102

105

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Nanoparticles of indium, indium hydroxide, and indium oxide were synthesized and evaluated for their electrocatalytic abilities in the reduction of CO 2 to formate. These nanoparticles were characterized with several microscopic and spectroscopic techniques in order to investigate their structure and surface features. Their electrochemical behavior was also probed through voltammetry and bulk electrolysis. faradaic efficiencies approaching 100% were achieved on these particles at potentials as positive as −1.3 V vs. Ag/AgCl, which represents a significant decrease in the overpotential compared to that observed using bulk indium electrodes. The nanostructuring of the particles and the partial surface oxidation of the indium nanoparticles to yield catalytic surface indium hydroxide species are implicated in the high efficiencies at low overpotentials. Recent decades have seen the rapid rise in the amounts of carbon dioxide, a greenhouse gas, present in both the atmosphere and the oceans, as well as a concomitant increase in global temperatures. 1This heating trend is predicted to amplify if net CO 2 emissions from fossil fuels continue to grow unabated, leading to a mean surface temperature increase of up to 4• C by 2100. 2 Therefore, a move away from fossil fuels toward renewable sources of energy such as wind and solar is essential for the long-term maintenance of the environment.The reduction of carbon dioxide to fuels and chemicals is an important component of a future energy portfolio based on renewable sources that seeks to mitigate carbon levels. The formation of useful chemicals from CO 2 rather than petroleum decreases the net CO 2 emissions and reduces reliance on oil. Generating high energy density carbon-based fuels, though only carbon-neutral and not carbonnegative, aids in load-leveling with intermittent power sources, leading to the production of fuels during periods of high output and the consumption during periods of low output.The electrochemical reduction of CO 2 on metal electrodes in aqueous solution has been studied for decades.3 Heavy post-transition metals, including indium, tin, lead, and bismuth yield predominantly formate, with small amounts of CO and H 2 as well. These metals have high overpotentials for water reduction, which allows them to be more selective for CO 2 reduction than most transition metals. However, the CO 2 reduction overpotentials are also fairly large, typically on the order of 1 V, significantly decreasing the energy efficiency of conversion. These metals have been proposed to reduce CO 2 in a oneelectron rate-determining step to the weakly adsorbed or free CO 2•− radical anion, which can then be protonated and reduced by another electron to yield formate.3 However, the formal redox potential for this process is −1.85 V vs. SHE, 4 considerably more negative than the potentials at which products are formed.Recent, more in-depth investigations on the mechanism of formate production on these metals have led to a greater understanding of the role of surface species in th...

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Surfactant Removal for Colloidal Nanoparticles from Solution Synthesis: The Effect on Catalytic Performance

Cited by 448 publications

References 28 publications

Untangling the Role of the Capping Agent in Nanocatalysis: Recent Advances and Perspectives

Untangling the Role of the Capping Agent in Nanocatalysis: Recent Advances and Perspectives

Engineering Surface Ligands of Noble Metal Nanocatalysts in Tuning the Product Selectivity

Enhanced Carbon Dioxide Reduction Activity on Indium-Based Nanoparticles

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