Spontaneous Phase Segregation Enabling Clogging Aversion in Continuous Flow Microfluidic Synthesis of Nanocrystals Supported on Reduced Graphene Oxide

Eliminating clogging in capillary tube reactors is critical but challenging for enabling continuous-flow microfluidic synthesis of nanoparticles. Creating immiscible segments in a microfluidic flow is a promising approach to maintaining a continuous flow in the microfluidic channel because the segments with low surface energy do not adsorb onto the internal wall of the microchannel. Herein we report the spontaneous self-agglomeration of reduced graphene oxide (rGO) nanosheets in polyol flow, which arises because the reduction of graphene oxide (GO) nanosheets by hot polyol changes the nanosheets from hydrophilic to hydrophobic. The agglomerated rGO nanosheets form immiscible solid segments in the polyol flow, realizing the liquid–solid segmented flow to enable clogging aversion in continuous-flow microfluidic synthesis. Simultaneous reduction of precursor species in hot polyol deposits nanocrystals uniformly dispersed on the rGO nanosheets even without surfactant. Cuprous oxide (Cu2O) nanocubes of varying edge lengths and ultrafine metal nanoparticles of platinum (Pt) and palladium (Pd) dispersed on rGO nanosheets have been continuously synthesized using the liquid–solid segmented flow microfluidic method, shedding light on the promise of microfluidic reactors in synthesizing functional nanomaterials.

[1]  B. B. Mulik,et al.  Electrocatalytic Ethanol Oxidation on Cobalt–Bismuth Nanoparticle-Decorated Reduced Graphene Oxide (Co–Bi@rGO): Reaction Pathway Investigation toward Direct Ethanol Fuel Cells , 2021 .

[2]  Taewook Kang,et al.  Microfluidic Multi‐Scale Homogeneous Mixing with Uniform Residence Time Distribution for Rapid Production of Various Metal Core–Shell Nanoparticles , 2020, Advanced Functional Materials.

[3]  B. K. Sahu,et al.  Graphene oxide surface chemistry regulated growth of SnO2 nanoparticles for electrochemical application , 2020 .

[4]  Trung Ngo Thanh,et al.  Electrocatalytic CO2 Reduction on CuOx Nanocubes: Tracking the Evolution of Chemical State, Geometric Structure, and Catalytic Selectivity using Operando Spectroscopy , 2020, Angewandte Chemie.

[5]  G. Guo,et al.  A scalable synthesis of ternary nanocatalysts for a high-efficiency electrooxidation catalysis by microfluidics. , 2020, Nanoscale.

[6]  Guangwen Chen,et al.  Continuous Synthesis of Reduced Graphene Oxide-Supported Bimetallic NPs in Liquid–Liquid Segmented Flow , 2020 .

[7]  N. Malmstadt,et al.  Self-optimizing parallel millifluidic reactor for scaling nanoparticle synthesis. , 2020, Chemical communications.

[8]  Y. Huh,et al.  Electroactive Ultra-Thin rGO-Enriched FeMoO4 Nanotubes and MnO2 Nanorods as Electrodes for High-Performance All-Solid-State Asymmetric Supercapacitors , 2020, Nanomaterials.

[9]  Yafei Li,et al.  Highly efficient hydrogen production from hydrolysis of ammonia borane over nanostructured Cu@CuCoOx supported on graphene oxide. , 2020, Journal of hazardous materials.

[10]  G. Guo,et al.  Visual and real-time imaging focusing for highly sensitive laser-induced fluorescence detection at yoctomole levels in nanocapillaries. , 2020, Chemical communications.

[11]  John X. J. Zhang,et al.  Microfluidics-enabled rational design of ZnO micro-/nanoparticles with enhanced photocatalysis, cytotoxicity, and piezoelectric properties. , 2019, Chemical engineering journal.

[12]  R. Bhargava,et al.  On-demand Milifluidic Synthesis of Quantum Dots in Digital Droplet Reactors. , 2019, Industrial & engineering chemistry research.

[13]  G. Garnweitner,et al.  Microfluidic synthesis of metal oxide nanoparticles via the nonaqueous method , 2018, Chemical Engineering Science.

[14]  A. Kulkarni,et al.  Insights in the Diffusion Controlled Interfacial Flow Synthesis of Au Nanostructures in a Microfluidic System. , 2017, Langmuir : the ACS journal of surfaces and colloids.

[15]  G. Guo,et al.  Enabling Colloidal Synthesis of Edge-Oriented MoS2 with Expanded Interlayer Spacing for Enhanced HER Catalysis. , 2017, Nano letters.

[16]  J. Köhler,et al.  Gold nanocubes – Direct comparison of synthesis approaches reveals the need for a microfluidic synthesis setup for a high reproducibility , 2016 .

[17]  Andrew J. deMello,et al.  Synthesis of Cesium Lead Halide Perovskite Nanocrystals in a Droplet-Based Microfluidic Platform: Fast Parametric Space Mapping. , 2016, Nano letters.

[18]  Younan Xia,et al.  Toward continuous and scalable production of colloidal nanocrystals by switching from batch to droplet reactors. , 2015, Chemical Society reviews.

[19]  G. Guo,et al.  One-Step, Facile and Ultrafast Synthesis of Phase- and Size-Controlled Pt-Bi Intermetallic Nanocatalysts through Continuous-Flow Microfluidics. , 2015, Journal of the American Chemical Society.

[20]  S. Bagheri,et al.  Graphene Supported Heterogeneous Catalysts: An Overview , 2015 .

[21]  John C. deMello,et al.  Segmented Flow Reactors for Nanocrystal Synthesis , 2013, Advanced materials.

[22]  Jintu Fan,et al.  Fabrication of hybrids based on graphene and metal nanoparticles by in situ and self-assembled methods. , 2011, Nanoscale.