Recent developments in catalysis with Pickering Emulsions

Chang, Fuqiang; Vis, Carolien M.; Ciptonugroho, Wirawan; Bruijnincx, Pieter C. A.

doi:10.1039/d0gc03604h

Cited by 83 publications

(54 citation statements)

References 132 publications

(160 reference statements)

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“…These rely on surface patches with different physicochemical (e.g., catalytic) properties for propulsion in self‐generated gradients. [ 1 ] In fact, Janus‐structured catalysts are of general research interest as a means to obtain advanced biphasic reaction media via Pickering emulsions [ 9 ] (e.g., for Pickering interfacial catalysis [ 10 ] ), and for the opportunities they provide to engineer heterojunctions [ 11 ] to design more efficient photocatalytic materials with enhanced electric field localization and reduced charge recombination. Returning to their use in active matter, Janus catalytic swimmers do not need external actuation, and only require a chemical fuel source to move.…”

Section: Introductionmentioning

confidence: 99%

Microswimmers from Toposelective Nanoparticle Attachment

Bailey

Grillo

Spencer

et al. 2021

Adv Funct Materials

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Microswimmers hold promise for applications ranging from targeted delivery to enhanced mixing at the microscale. However, current fabrication techniques suffer from limited throughput and material selection. Here, a versatile route enabling the synthesis of microswimmers from off-the-shelf micro-and nano-particles is demonstrated. The protocol hinges on the toposelective attachment of photocatalytic nanoparticles onto microparticles, exploiting a multi-functional polymer and a Pickering-wax emulsification step, to yield large quantities of photo-responsive active Janus particles. The polymer presents both silane and nitrocatechol groups, binding silica microspheres to a range of metal oxide nanoparticles. The Pickering-wax emulsions protect part of the microspheres' surface, enabling asymmetric functionalization, as required for self-propulsion. The resulting photocatalytic microswimmers display a characteristic orientation-dependent 3D active motion upon ultra-violet illumination, different from that conventionally described in the literature. By connecting the extensive library of heterogeneous nanoparticle photocatalysts with the nascent field of active matter, this versatile material platform lays the groundwork toward designer microswimmers, which can swim by catalyzing a broad range of chemical reactions with potential for future applications.

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Section: Introductionmentioning

confidence: 99%

Microswimmers from Toposelective Nanoparticle Attachment

Bailey

Grillo

Spencer

et al. 2021

Adv Funct Materials

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“…A very efficient way to increase interfacial area, and hence reaction and/or extraction efficiency, is to place a solid at the liquid/liquid interface and create an emulsion. Recently, such solid particle‐stabilized emulsions, so‐called Pickering emulsions (PEs) have been receiving increased attention for their application in biphasic catalysis [17–19] . The solid particles at the boundary layer in PEs serve to compartmentalize and to protect the dispersed phase from the continuous phase, for example, allowing multiple reactions to be mediated consecutively [20–22] .…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis

et al. 2021

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Nature provides much inspiration for the design of multistep conversion processes, with numerous reactions running simultaneously and without interference in cells, for example. A key challenge in mimicking nature's strategies is to compartmentalize incompatible reagents and catalysts, for example, for tandem catalysis. Here, we present a new strategy for antagonistic catalyst compartmentalization. The synthesis of bifunctional Janus catalyst particles carrying acid and base groups on the particle's opposite patches is reported as is their application as acid‐base catalysts in oil/water emulsions. The synthesis strategy involved the use of monodisperse, hydrophobic and amine‐functionalized silica particles (SiO2−NH2−OSi(CH3)3) to prepare an oil‐in‐water Pickering emulsion (PE) with molten paraffin wax. After solidification, the exposed patch of the silica particles was selectively etched and refunctionalized with acid groups to yield acid‐base Janus particles (Janus A–B). These materials were successfully applied in biphasic Pickering interfacial catalysis for the tandem dehydration‐Knoevenagel condensation of fructose to 5‐(hydroxymethyl)furfural‐2‐diethylmalonate (5‐HMF‐DEM) in a water/4‐propylguaiacol PE. The results demonstrate the advantage of rapid extraction of 5‐hydroxymethylfurfural (5‐HMF), a prominent platform molecule prone to side product formation in acidic media. A simple strategy to tune the acid/base balance using PE with both Janus A–B and monofunctional SiO2−NH2−OSi(CH3)3 base catalysts proved effective for antagonistic tandem catalysis.

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“…10 Particle-stabilized emulsion, also known as Pickering emulsion, has received considerable interest in biphasic enzymatic catalysis. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] The novel platform combines the advantages of enhanced stability, improved biocompatibility, and ease of product/catalyst separation. 13,14 Given that the involved reactants are organic-soluble, water-in-oil (w/o) Pickering emulsions with oil as the continuous phase are more preferable for feasible extraction of products and reuse of catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] The novel platform combines the advantages of enhanced stability, improved biocompatibility, and ease of product/catalyst separation. 13,14 Given that the involved reactants are organic-soluble, water-in-oil (w/o) Pickering emulsions with oil as the continuous phase are more preferable for feasible extraction of products and reuse of catalysts. In pioneering work, Wu et al utilized silica nanoparticles as emulsifiers to prepare w/o Pickering emulsion with enzyme loaded in the internal aqueous phase for biocatalysis.…”

Section: Introductionmentioning

confidence: 99%