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For photoelectrochemical hydrogen production, a non-noble catalyst is directly patterned onto the photocathode using a light-guided electrodeposition technique.

Bromide/polybromide-based ionic liquids have recently gained attention as energy storage devices because of their dual roles as a solvent and a redox pair. However, their redox reaction is accompanied by the generation of emulsion at the electrode surface, which makes the study of their electrochemical mechanism highly challenging. We investigated the current amplification of a single droplet of 1-ethyl-1-methylpyrrolidinium polybromide (MEPBr2n+1), which is a Br–/Br2n+1 –-based ionic liquid. The heterogeneous electron transfer of Br–/Br3 – at the electrode is very fast. However, it still limits the overall reaction of this electrochemical system. Assuming free diffusion, the calculated diffusion coefficient of Br–/Br3 – in a MEPBr2n+1 droplet is surprising and is an order greater than that of proton conduction following Grotthuss-like hopping. In situ Raman spectroscopy confirmed that the polybromide composition in the droplet varies during electrolysis and correlated the swift charge propagation with the polybromide network in the MEPBr2n+1 phase.

The functional surface features of living creatures are driven by the complex morphology of periodically arranged micro/nanoscale structures. Various fabrication processes have been devised mimic the performance of natural features; these methods morph hierarchical and multi-leveled pillar arrays, such as top-down, bottom-up, and a hybrid of top-down and bottom-up processes.Different methodologies are employed depending on the materials, such as polymeric composites, metal oxides, metals, and carbon nanotubes. In this review, we discuss the shape-reconfiguration of stimuli-responsive micro/ nanopillar arrays achieved by capillary force, light, magnetic field, and heat. In particular, photo-and magnetic actuation of pillar arrays revealed programmability according to the arrangement of the liquid crystal molecules or magnetic particles by remote control. Furthermore, applications of micro/nanopillar arrays, such as adhesives, omniphobicity, optics, and biomedical technologies, are also discussed.