Photovoltaic systems are widely applied but intermittent. Osmotic power can generate electricity from ion concentration gradients, but it is difficult to maintain high efficiency over large membrane areas for viable application. Here, we developed a large-area Nafion/graphene oxide membrane with optimized energy barrier engineering for efficient osmotic power generation, achieving a record power density of 8.5 W m-2 (0.3 V, 12 mA) with a single-cell device on a 1 cm2 scale, more than one order of magnitude higher than previous reports. The output remains stable day and night, under daytime one-sun illumination, enabling non-intermittent green energy conversion. A large-scale module consisting of 400 units connected in series delivers 100 V to directly power electronic devices such as mobile phones. Moreover, we successfully fabricated a 1,000 cm2 device with the Nafion/graphene oxide membrane, achieving 0.66 W m-2 (0.3 V, 0.9 A) with a single device, setting a record for large-area osmotic systems.

To realize an ideal photocatalyst for CO2 photoreduction to CH4, developing an "all-in-one" optimization system that targets every elementary step in the photocatalytic CO2 methanation is highly desirable but remains a great challenge. Here, we present a unique rare-earth modulation strategy to collectively regulate the behaviors of light adsorption, charge separation, reactant supply, and active sites in the photocatalysis process for achieving highly active, selective, stable, and economic CO2 methanation photocatalysts. Particularly, the proof-of-concept CuPr alloy quantum dots-decorated TiO2 photocatalysts optimized with rare-earth elements and compositions (denoted as TiO2-Cu7Pr1 AQDs) exhibit outstanding photocatalytic activity with a CH4 production rate of 792.6 lmol g-1 h-1 and electron selectivity of 96.6%, surpassing various state-of-the-art photocatalysts ever reported. Comprehensive experiments and theoretical analysis demonstrate that rare-earth regulation can create multiple advantageous conditions targeting different steps, which enable TiO2-Cu7Pr1 to fulfill the essential criteria for an ideal highefficiency non-noble-metal photocatalyst for CO2 methanation, including favorable light absorption, enriched reactant supply of CO2/H+, rapid carrier separation and transfer, as well as highly active methanation site. The proposed all-in-one design concept in this work not only develops a noble-metal-free photocatalyst with ultrahigh performance toward photocatalytic CO2 methanation but also provides significant inspiration in various photocatalysis applications. (c) 2026 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Pristine mono- or few-layer graphene lacks a permanent dipole due to its centrosymmetric lattice, making ferroelectricity unlikely. However, ABCB tetralayer, the simplest mixed-stacked graphene, breaks both inversion and mirror symmetry, thus exhibiting intrinsic out-of-plane polarization arising from asymmetric charge carrier distribution across its layers. We report robust ferroelectric behavior in ABCB tetralayer graphene encapsulated in hexagonal boron nitride, in the moiré-less limit. The device exhibits pronounced hysteresis in resistance under both top and bottom gate modulation, with the effect persisting up to room temperature. This hysteresis originates from reversible layer-polarized charge reordering, driven by gate-induced transitions between ABCB and BCBA stacking configurations. Our findings establish stacking-order-induced symmetry breaking as a fundamental route to ferroelectricity and open pathways for nonvolatile memory applications.

As a manipulation platform exhibiting distinct advantages at micro/nanoscales, microrobots demonstrate significant application potentials across biological, medical, and chemical engineering domains. However, current research for microrobot design and actuation predominantly focuses on aqueous and physiological fluid environments, and thus effective ways for driving microrobots to operate in viscous oil-based media remains are still limited. To address this issue, we develop an acoustic magnetic hybrid microrobot leveraging bubble and fin structures for acoustic propulsion as well as magnetic coating layer for controlled navigation. With acoustic stimuli, the microrobot can achieve 2-6 mm/s motion speed propelled by the oscillating bubble. With magnetic steering, the microrobot can be controlled to move along arbitrary paths. Experimental results demonstrate that the microrobot can rapidly and accurately navigate to target locations in oil environments. Secondary acoustic radiation forces can capture target particles with different sizes, then transport them to target location and release. The proposed acoustic-magnetic hybrid manipulation strategy enables microrobots to operate in viscous oil environments, offering a new paradigm to unlock the environment adaptability for complex application scenarios.

Electrokinetic transport under nanoconfinement is governed by solid-liquid interfacial interactions. Although electrical modulation offers a facile route to regulate ion transport, existing approaches often use a transmembrane bias requiring continuous external driving, which imposes an axial electric field and thereby complicates mechanistic interpretation. Here, we report an electrolyte/interfacial voltage-gating strategy in which a gate voltage is introduced between a monolayer molybdenum disulfide nanopore and a counter electrode without intentionally applying a transmembrane voltage bias. This configuration enables gate-tunable electrokinetic transport and induces a pronounced polarity reversal of pressure-driven streaming current within a narrow subvolt gating window. The reversal is consistent with gate-controlled modulation of the effective interfacial charge state, which changes the excess mobile ionic charge transported by pressure-driven flow. These findings establish interfacial voltage gating as a route for regulating pressure-driven electrokinetic transport in nanofluidic systems, providing a foundation for adaptive ionic and energy-harvesting devices.

Quantum friction has been shown to dominate the singular behavior of nanoscale water flows, especially for water-graphene systems of keen current interest. In contrast to classical friction resulting solely from the surface properties of solids, we here show that the quantum friction at water-graphene interface is non-additively amplified by the practically required substrate through a newly developed method at an ab initio level. The amplification of quantum friction reaches one order of magnitude for AB-stacked bilayer graphene and up to four orders of magnitude for monolayer graphene on Ni(111) substrate; the latter surpasses the cumulative friction of isolated graphene and Ni(111) by twenty times. The interfacial electronic interaction between graphene and substrate, not the electrostatic coupling, is revealed to serve as the primary driver of the friction amplification. These findings suggest substrate engineering as a transformative strategy to tune friction at fluid-solid interfaces without surface modification.

The expansion or shrinkage of elastic membranes when wetted by liquids has long been a theoretical concept, yet remained untested due to the extremely small in-plane deformations involved. Here, we leverage out-of-plane bulging to verify that water wetting can indeed cause graphene bubbles to expand. Notably, we find that the graphene bubble becomes "softer" when in contact with water. By incorporating surface tension into Vlassak's model, we obtain a revised equation that accurately attributes the expansion of graphene to the reduction of surface tension at the graphene-water interface. Furthermore, we exploit the underlying principle to actively program deformation and vibrational dynamics of graphene membranes by applying an electric field at the solid-liquid interface. Our results provide fundamental mechanistic insights into the crucial role of surface tension for elastic membranes and open up new avenues for designing responsive structures driven by surface tension.

Creating multiple polarization states in a single ferroelectric device is of use in neuromorphic computing to enhance computational resolution. However, the number of stable polarization states in such systems is typically limited to 32 at room temperature. Here we report the manipulation of thousands of non-volatile polarization states at room temperature in a sliding ferroelectric transistor that is composed of an aligned graphene monolayer atop hexagonal boron nitride. Solely regulated by source–drain pulses, more than 36 quasi-continuous polarization states can be generated at one doping level. Superimposing a gate voltage during the source–drain pulses can reversibly regulate the graphene Fermi energy between 84 doping levels, promoting the number of physically distinct polarization states to 3,024 (36 states × 84 doping levels). These polarization states can sustain for over 105 s and could potentially persist for 10 years. The abundant polarization states probably stem from the motion of polar domain walls and the moiré potential localizing the injected carriers. The simulation of during-training quantization in a deep residual network using the 3,024 polarization states shows a floating-point-comparable recognition accuracy (around 93.53

Emerging hydrovoltaic technology holds great promise for harvesting low-grade thermal energy in ambient environment via natural water evaporation from functional nanomaterials. Cellulose-based hydrovoltaic materials have been attracting great research interest for water evaporation electricity generation (EEG), as cellulose has abundant surface functional groups and can be derived from plentiful natural materials. However, reported cellulose-based hydrovoltaic devices still exhibit relatively low output performance, for example, the output voltage is generally below 1 V. Herein, we developed a nanocomposite cellulose membrane by depositing bismuth oxyiodide on the nanofibers through a two-step liquid-vapor method. The nanocomposite membrane achieved a high output voltage, approximately 3.7 V, about three-fold that of the pristine cellulose membrane. This represents the highest output voltage reported for cellulose-based hydrovoltaic devices to date and ranks among the top levels of all hydrovoltaic devices. Mechanistic studies reveal that the output enhancement primarily originates from the evaporating potential induced by semiconductive BiOI nanoparticles on the membrane surfaces. Owing to the high voltage output, the integrated device can power commercial electronics like LEDs. This work demonstrates a promising nanocomposite strategy for advancing cellulose-based hydrovoltaic devices.

When an elastic membrane is deformed, the external work is stored not only as volume-related elastic strain energy but also as area-related surface energies, since the total membrane area changes. The latter contribution is challenging to quantify experimentally, especially for ultrathin membranes. Here, we demonstrate that such surface effects can be revealed through indentation by comparing tests performed at gas and liquid interfaces. Specifically, using monolayer graphene indented across N2-graphene and water-graphene interfaces, we show that graphene indented against water appears significantly softer-a signature of interfacial energetics favoring the water-graphene configuration. A membrane theory incorporating both elasticity and surface forces quantitatively reproduces the measured force-displacement curves, enabling the extraction of the interfacial tension difference and, in turn, membrane's wettability. These results establish indentation as a probe of solid-liquid surface tension at the membrane limit and highlight that surface effects-often regarded as negligible in 2D materials-must be carefully accounted for in applications ranging from straintronics to nanofluidics.

Electricity generation from interfacial molecular motion holds great promise for harvesting micro/nano energy for carbon neutrality and sustainable off-grid power. Carbon materials and noble metals are normally treated as chemically inert electrodes even in such systems, potentially overestimating physical contributions and underutilizing chemical processes. Here, we achieve an ultrahigh current output via a dynamic liquid-hydrogel interface through a synergistic physicochemical approach, by bridging a static graphite electrode and a dynamic hydrogel-coated platinum electrode in saline. The hydrogel film containing poly(acrylic acid) is critical to both processes. Polyanionic poly(acrylic acid) serves as a proton reservoir, neutralizing hydroxide ions from the oxygen reduction reaction at the platinum surface (oxygen is ubiquitous in air), thereby providing a continuous chemical current; sharp ion concentration gradients form near the hydrogel/saline interface due to the Donnan effect, enabling physical charge separation by liquid flow during periodic immersion-withdrawal cycles. Overall, this design delivers a direct-current output with a peak current density of 2432 & micro;A cm-2 and a transferred charge density over 1000 mC m-2 per cycle, surpassing existing counterparts. This work offers new insight into constructing high-performance hydrovoltaic devices as green, scalable energy sources for self-powered miniaturized systems and emerging energy infrastructures.

Biological nervous systems rely on distinct spiking frequencies across a wide range for perceiving, transmitting, processing, and executing information. Replicating this frequency range in an artificial neuron would facilitate the emulation of biosignal diversity but it remains challenging. Here, we develop an ion-electronic hybrid artificial neuron by compactly integrating a nonlinear electrochemical element with a solid-state memristor. This hybrid neuron employing a minimalist architecture exhibits a tunable spiking frequency spanning five orders of magnitude, significantly surpassing the capability of artificial neurons based on electronic devices. Notably, stimuli-dependent ion fluxes enable inherent afferent sensing of liquid flow, temperature, and chemical constituents, eliminating the need for separate, bulky sensors. Connection to biomotor nerves facilitates muscle actuation with frequency-regulated modes. The frequency encoding of a hybrid neuron array allows for the recognition of handwritten patterns. This hybrid neuron design, taking advantage of both ionic and electronic features, offers a promising approach for advanced e-skin and neurointerface technologies.

The vast energy stored in the ocean, which receives an average solar power of approximate to 60 000 TW per year, surpasses human energy consumption by three orders of magnitude. Harnessing even a small fraction of it holds great promise in addressing global energy and water crises. Here, an integrated device that achieves unprecedented power density up to 1.1 W m-2 with excellent stability through a salinity concentration gradient induced by solar evaporation, while simultaneously producing clean water at a rate of 1.25 kg m-2 h-1 under one sun irradiation is presented. The remarkable electricity generation capability stems from the unique interlayer structure of polyaniline-graphene oxide-MnO2 (PANI@GO/MnO2) electrodes, enabling the recovery of electrochemical potentials from a wide range of ion salinity concentrations within the device and the additional Donnan potential generated by the anion-exchange membrane. Furthermore, periodic flipping of the device effectively reactivates the electrodes and suppresses salt accumulation, enabling long-term operation. Notably, a prototype device of 8 x 25 cm2 exhibits a short-circuit current of 10 mA and an open-circuit voltage of 10.2 V, as well as a clean water production rate of 24.8 g per hour. These findings shed light on the reliable technology for power and freshwater supply in marine environments.

Large-scale growth of high-crystalline-quality two-dimensional (2D) semiconductor films is a prerequisite for next generation of electronics and optoelectronics. As a representative case, 2D transition metal dichalcogenides (TMDCs) are usually grown by a chemical vapor deposition (CVD) method based on a van der Waals (vdW) epitaxy mechanism. Commonly used silicon or Al2O3 (sapphire) substrates have either nanoscale roughness or step bunches, and the grown TMDC domains usually show diverse shapes, random orientation alignments with the substrates, and uncontrollable crystalline quality. These problems call for ideal substrates for the vdW epitaxial growth of 2D semiconductors. In this work, we employed graphene monolayers transferred on sapphire wafer as the substrate to investigate the vdW epitaxy of monolayer MoSe2 using a MOCVD technique. We found that the graphene is essentially the substrate, as it shields the influence of the underlying sapphire. Compared with bare sapphire substrates, the MoSe2 domains grown on graphene not only show an equilateral triangular shape and mirror symmetry with respect to the graphene lattice in a wide range of parameter windows, but also the domain size, nucleation density, and growth rate can be well controlled by the processing temperatures, pressures, and precursor flows. These results suggest that graphene film is a proper substrate for vdW epitaxy of 2D semiconductors. We further quantitatively investigated the interfacial forces between MoSe2 domains and graphene using scanning probe microscopy to reveal the weak vdW interaction. Our work highlights the importance of substrates for the vdW epitaxial growth of 2D semiconductors and paves the way for substrate optimization in the 2D film growth and device integrations.

Osmotic energy, often called blue energy, is a promising renewable resource. Nanofluidic reverse electrodialysis, which utilizes nanoflows to generate power, has gained intensive attention as a promising technology for harvesting osmotic energy. However, efficiency challenges have hindered its widespread application. In this study, we proposed a strategy to enhance the osmotic energy harvesting efficiency by applying a pressure gradient, taking easily accessible anodic aluminum oxide membranes as the representative model. Our results demonstrate that the pressure difference across the membrane gives rise to a substantial enhancement in osmotic current for a wide range of pore sizes and salt ions. Specifically, a 1 bar pressure difference results in a 130% increase in osmotic current under a 1000-fold concentration gradient of potassium chloride solution. The pressure-enhanced osmotic power generation is attributed to the additional ion flux driven by pressure gradient and thus a higher electrical conductivity across the membrane. These findings highlight the potential of pressure-driven enhancements to improve the efficiency of blue energy technologies.

Unipolar ion flow in nanochannels, enabled by the overlapping electrical double layers at the water-solid interfaces, is essential in various energy conversion processes, such as osmotic and hydrovoltaic energy harvesting. Photoinduced charges in semiconductors have been reported to modulate solid surface charges and thus the selective transport of ions. Here, it is revealed that photoinduced charges can dynamically couple with the unipolar ion flow, instead of surface modulation, contributing to photogated water-evaporation-induced electricity. Specifically, the voltage output of the hydrovoltaic device, constructed by semiconducting tungsten oxide (WO3) nanoparticles, is tuned from 2.7 to 0.2 V with high reproducibility by varying light intensities. Mechanistic investigations implied that photogating is attributed to the directional transport of photoinduced charges in WO3, opposite to the unipolar ion flow. The voltage recovery dynamics after illumination cessation are found to be closely related to the ion concentration, explained by a circuit model involving the resistive and capacitive characteristics that depend on the charge carriers in the solid and solution. A new approach for low-concentration ion detection is further developed based on light and ion-induced regulation of evaporation-induced electricity. The findings offer new insights into the coupling of charge carriers in solid and liquid and can advance the applications of hydrovoltaic technologies.

Collective behavior enables groups of organisms to achieve feats far exceeding individual capability. Inspired by this, we present a novel droplet-based electricity generator that leverages the collective dynamics of multiple water droplets to significantly enhance electrical output, achieving orders of magnitude improvement compared with single-droplet devices. It is revealed that grouped water droplets, although spatially separated, coordinate via charge exchange with a solid surface and external charge transfer. Consequently, the solid surface charge density is significantly enhanced, elevating the charge transfer. This collective effect readily generates peak voltages exceeding one kilovolt, sufficient for air ionization and nitrogen fixation, with potential applications in nutrient production. We anticipate that this collective strategy will significantly advance the design and applications of droplet-based hydrovoltaic devices.

The ultrathin water films on solid surfaces are ubiquitous and play critical roles in corrosion, energy conversion and storage, mass transfer, catalysis, and so on. With advances in theoretical calculations and experimental techniques, researchers have been able to study and comprehend the structure and properties of the ultrathin water films on solid surfaces more intuitively, which could contribute to more effective utilization of this aqueous interface in distinct domains. In this review, we summarize the formation mechanism and research means of ultrathin water films, and delve intensively into the structures and properties of two types of water: one is the water adsorbed on solid surfaces, and the other is the precursor film generated at the edge of bulk water diffusion. We also introduce some open-ended questions and limitations, hoping to provide a perspective for investigation in this domain.

Recent flexible electronics with conformal interfaces between devices and human bodies are prone to receive circuit failure caused by uncontrollable cracking during physiological movements. A structural engineering strategy is reported that utilizes capillary-stabilized liquid bridges to spontaneously mediate crack initiation, propagation, and coalescence for film reinforcement. Specifically, rigid nanowire array are decorated onto flexible polydimethylsiloxane substrates and the nanoscale gaps between the nanowires are filled with non-volatile ionic liquids to form well-regulated meniscus. Using metal films as a model, it is found that stretchability of an Au film deposited on this meniscus exceeds that of its flat counterpart (180 vs 30%). In-situ optical observations and fluid dynamics analyses show that liquid bridge forces mechanically hinder the propagating of crack fronts and simultaneously initiate new cracks in different locations, leading to dispersed small cracks at strains below 80%. This scattering of cracks prevents the concentrated propagation and merging of cracks into penetrating fractures, with effective electrical percolation of Au films even under a high strain of 160%, which contrasts sharply with the counterparts without liquids where penetrating cracks occur at a small strain of ≈10%. Results indicate fluid mechanics as a versatile approach to reprogram film cracking for high-performance electronics.