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The integration of two-dimensional (2D) nanochannels with differing properties presents a promising avenue for mimicking ion transport processes in biological systems. In this study, a bioinspired Janus nanochannel membrane (BJNM) is developed by incorporating intercalated montmorillonite (MMT) and graphene oxide (GO) nanosheets. The asymmetric characteristics in chemical composition, structure, and charge distribution confer the BJNM with the ability to rectify ion transport, as evidenced by nonlinear current-voltage relationships. Through optimization of the electrolyte solution and applied voltage range, a notable rectification ratio of 40.9 is achieved. The underlying mechanism of ion rectification is explored through numerical simulations, highlighting the significance of 2D heterojunctions. These findings provide valuable insights for the design of nanofluidic systems tailored for precise ion transport, biosensing applications, and energy conversion processes. [Display omitted] • Bioinspired two-dimensional nanochannel membranes with Janus heterostructures were fabricated. • The highly rectified ion transport was achieved due to the multiple asymmetries of the membrane. • A remarkable rectification ratio of 40.9 was obtained through the optimization of external factors. • The ion transport mechanism was validated by experimental measurements and theoretical simulations. [ABSTRACT FROM AUTHOR]

Biomimetic nanochannels are desirable materials for high‐efficiency utilization of osmotic energy. However, the current power generation performance is limited by the low ion selectivity and ion flux. Here, novel nanochannels with double‐network structure based on cellulose nanofibers intercalated with carbon nanotubes are demonstrated. The relatively high cationic selectivity and ion flux are obtained due to the enlarged charge polarity and space for ion transport in the double‐network nanochannel, which is favorable for the osmotic power conversion. To the best of the authors' knowledge, the power density under 50‐fold NaCl (4.67 W m−2) outperforms most state‐of‐the‐art nanochannel membranes with the same test conditions. By applying the concentration gradient between artificial (50‐fold KCl) and real seawater/river water, a high power density of 5.53 and 6.51 W m−2 can be achieved respectively, which exceeds the standard output of the ion‐selective membrane for commercialization. The design of the biomimetic double‐network nanochannels provides a new platform for controllable ion transport and high‐performance power generation. [ABSTRACT FROM AUTHOR]

The design of an electrode surface is critical to the oxygen evolution reaction (OER) during electrochemical water splitting since the catalytic activity depends strongly on surface characteristics, such as the coating uniformity of the catalysts, electrolyte wetting, and the gas‐bubble release ability. Here, nonprecious‐metal electrocatalysts (MnO nanowires) are electrochemically deposited on the surface of a porous gold microgrid. The discontinuous solid–liquid contact lines, which are formed by the microgrids during the liquid‐phase electrochemical reaction, generate MnO nanowires with high coating uniformity. The micro/nanostructure of the electrode induces a superhydrophilic surface, which facilitates the wetting of the alkaline electrolyte and increases the electrochemical active surface area. Simultaneously, the underwater superaerophobicity of the electrode promotes the release of the oxygen products, thus reducing the occupation of the catalytic sites by the gas bubbles. The synergistic effect of electrolyte wetting and gas release ensures that this superhydrophilic/superaerophobic electrode exhibits a current density of 10 mA cm−2 for the OER at an overpotential of 530 mV in 0.1 m KOH, placing the catalyst among the best MnO catalysts for OER. This work avails a new basis for synergistically optimizing the synthesis methods (electrolyte wetting and gas‐bubble release) toward high‐performance OER electrodes. [ABSTRACT FROM AUTHOR]

The controllable ion transport in the photoreceptors of rod cells is essentially important for the light detection and information transduction in visual systems. Herein, inspired by the photochromism-regulated ion transport in rod cells with stacking structure, layered ion channels have been developed with a visual photochromic function induced by the alternate irradiation with visible and UV light. The layered structure is formed by stacking spiropyran-modified montmorillonite 2D nanosheets on the surface of an alumina nanoporous membrane. The visual photochromism resulting from the photoisomerization of spiropyran chromophores reversibly regulates the ion transport through layered ion channels. Furthermore, the cooperation of photochromism and pH value achieves multiple switchable states of layered ion channels for the controllable ion transport mimicking the biological process of the visual cycle. The ion transport properties of these states are explained quantitatively by a theoretical calculation based on the Poisson and Nernst-Plank (PNP) equations., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Efficient anode materials with porous structures have drawn increasing attention due to their high specific surface area, which can compensate for the slow reaction rate of electrochemical oxidation. However, the use of these materials is often limited due to their poor corrosion resistance. Herein, we report a facile scale-up method, by carbothermal reduction, for the preparation of porous niobium carbide to be used as an anode for the electrochemical oxidation of phenol in water. No niobium ions were detected when the anodes were under aggressive attack by sulfuric acid and under electrochemical corrosion tests with a current density less than 20.98 mA cm -2 . The porous niobium carbide was further modified by applying a ruthenium oxide coating to improve its catalytic activity. The removal rates of phenol and chemical oxygen demand by the RuO 2 /NbC anode reached 1.87 × 10 -2 mg min -1 cm -2 and 6.33 × 10 -2 mg min -1 cm -2 , respectively. The average current efficiency was 85.2%. Thus, an anti-corrosion, highly catalytically active and energy-efficient porous RuO 2 /NbC anode for the degradation of aqueous phenol in wastewater was successfully prepared., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Molybdenum disulfide (MoS 2 ) is a promising non-precious metal electrocatalyst for the hydrogen evolution reaction (HER). Herein, we have described an anodization route for the fabrication of porous MoS 2 electrodes. The active porous MoS 2 layer was directly formed on the surface of a Mo metal sheet when it was subjected to anodization in a sulfide-containing electrolyte. The Mo sheet served as both a supporter for MoS 2 electrocatalysts and a conductive substrate for electron transport. After optimizing the anodization parameters, the anodized MoS 2 electrode showed a high electrocatalytic activity with an onset potential of -0.18 V ( vs. RHE) for the HER, a Tafel slope of ∼101 mV per decade and an overpotential of 0.23 V at a current density of 10 mA cm -2 for the HER. These results indicate that our facile anodization strategy is an efficient route towards a high-activity MoS 2 electrode., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)