Microdrop generation with excellent controllability and volume precision is of paramount significance for a large variety of microfluidic applications. In this work, we propose a new configuration comprising only stripped electrodes of rectangular shape for the closed electrowetting-on-dielectric digital microfluidic (EWOD DMF) system and investigate its parallel microdrop generation outcomes via a numerical approach. The microfluidic droplet motion is solved by a finite-volume scheme on a fixed computational domain. The numerical model is verified by an experimental study of microdrop production from an EWOD DMF device with three different electrode designs. After model verification, we examine the influences of the equilibrium contact angle and the spacing of the microchannel on stripped electrode based microdrop generation outcomes and discover five different regimes including the phenomena of satellite droplet formation and separation cessation. Despite the various generation outcomes, the daughter droplet size is found to vary linearly with a dimensionless EWOD parameter κ*. More importantly, for all successful generations, the deviation of the daughter droplet size from that of the stripped electrode is smaller than 3.5%, which even reaches zero in proper conditions. This new configuration can be utilized as a convenient alternative for electrowetting-induced parallel microdrop production with excellent precision and controllability.

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High-performance, nonprecious metal catalysts with special morphologies and easy-to-recycle properties are essential for the treatment of environmental pollutants. Herein, CoFe nanoparticle-decorated reduced graphene oxide (RGO) catalysts were designed and successfully fabricated, and the catalyst was then used to reduce 4-nitrophenol into 4-aminophenol. Outstanding catalytic properties with a reduction rate constant of 4.613 min −1 were achieved due to the synergistic properties of the CoFe metal alloy and the high-conductivity RGO components in the catalysts. In addition, the catalyst was conveniently recovered via magnets due to its inherent magnetic properties. The facile preparation, outstanding catalytic performance, structural stability, and low material costs make the CoFe/RGO nanocatalyst a promising candidate for potential applications in catalysis.

A desirable counter electrode material for dye‐sensitized solar cells (DSSCs) needs to have superior electrocatalytic activity, low charge‐transfer resistance, and long‐term stability. Herein, the development of a composite of nitrogen‐doped carbon nano‐onions with modified reduced graphene (N‐CNOs/mGr) to achieve these merits is reported. The mGr network has high electrical conductivity to improve charge transfer; the N‐CNOs with pyridinic and graphitic N provide more electrocatalytic active sites for the reduction of I3− to I−, and the carbon composite demonstrates excellent electrochemical stability. The constructed DSSC with the N‐CNOs/mGr electrode presents better long‐term stability and a higher power conversion efficiency of 10.28% than those devices with conventional Pt (6.54%) and mGr (5.11%) electrodes. Therefore, the all carbon‐based composite will open up new opportunities for a variety of electrochemical device applications.

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