Three-dimensional (3D) printing technologies are emerging as an important tool for the manufacturing of electrodes for various electrochemistry applications. It has been previously shown that metal 3D electrodes, modified with metal oxides, are excellent catalysts for various electrochemical energy and sensing applications. However, the metal 3D printing process, also known as selective laser melting, is extremely costly. One alternative to metal-based electrodes for the aforementioned electrochemical applications is graphene-based electrodes. Nowadays, the printing of polymer-/graphene-based electrodes can be carried out in a matter of minutes using cheap and readily available 3D printers. Unfortunately, these polymer/graphene electrodes exhibit poor electrochemical activity in their native state. Herein, we report on a simple activation method for graphene/polymer 3D printed electrodes by a combined solvent and electrochemical route. The activated electrodes exhibit a dramatic increase in electrochemical activity with respect to the [Fe­(CN)6]4–/3– redox couple and the hydrogen evolution reaction. Such in situ activation can be applied on-demand, thus providing a platform for the further widespread utilization of 3D printed graphene/polymer electrodes for electrochemistry.

Light-driven micro/nanomotors represent the next generation of automotive devices that can be easily actuated and controlled by using an external light source. As the field evolves, there is a need for developing more sophisticated micromachines that can fulfill diverse tasks in complex environments. Herein, we introduce single-component BiVO4 micromotors with well-defined micro/nanostructures that can swim both individually and as collectively assembled entities under visible-light irradiation. These devices can perform cargo loading and transport of passive particles as well as living microorganisms without any surface functionalization. Interestingly, after photoactivation, the BiVO4 micromotors exhibited an ability to seek and adhere to yeast cell walls, with the possibility to control their attachment/release by switching the light on/off, respectively. Taking advantage of the selective motor/fungal cells attachment, the fungicidal activity of BiVO4 micromotors under visible illumination was also demonstrated. The presented star-shaped BiVO4 micromotors, obtained by a hydrothermal synthesis, contribute to the potential large-scale fabrication of light-powered micromotors. Moreover, these multifunctional single-component micromachines with controlled self-propulsion, collective behavior, cargo transportation, and photocatalytic activity capabilities hold promising applications in sensing, biohybrids assembly, cargo delivery, and microbiological water pollution remediation.

Additive manufacturing provides a unique tool for prototyping structures toward electrochemical sensing, due to its ability to produce highly versatile, tailored-shaped devices in a low-cost and fast way with minimized waste. Here we present 3D-printed graphene electrodes for electrochemical sensing. Ring- and disc-shaped electrodes were 3D-printed with a Fused Deposition Modeling printer and characterized using cyclic voltammetry and scanning electron microscopy. Different redox probes KFe(CN):KFe(CN), FeCl, ascorbic acid, Ru(NH)Cl, and ferrocene monocarboxylic acid) were used to assess the electrochemical performance of these devices. Finally, the electrochemical detection of picric acid and ascorbic acid was carried out as proof-of-concept analytes for sensing applications. Such customizable platforms represent promising alternatives to conventional electrodes for a wide range of sensing applications.

The interaction of laser pulses with thin grating targets, having a periodic groove at the irradiated surface, is experimentally investigated. Ultrahigh contrast (~10(12)) pulses allow us to demonstrate an enhanced laser-target coupling for the first time in the relativistic regime of ultrahigh intensity >10(19) W/cm(2). A maximum increase by a factor of 2.5 of the cutoff energy of protons produced by target normal sheath acceleration is observed with respect to plane targets, around the incidence angle expected for the resonant excitation of surface waves. A significant enhancement is also observed for small angles of incidence, out of resonance.

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