Ultra-low Voltage Research Articles

Exploring P-(Fe,V)-Codoped Metastable-Phase β-NiMoO4 for Improving the Performance of Overall Water Splitting.

It is especially essential to develop high-performance and low-cost nonprecious metal catalysts for large-scale hydrogen production. A large number of electrochemical catalysts composited by transition metal centers has been reported; however, it is still a great challenge to design and manipulate target electrocatalysts to realize high overall water-splitting activity at the atomic level. Herein, we develop totally new P-(Fe,V)-codoped metastable-phase β-NiMoO4. As an electrocatalyst, it can realize oxygen evolution at only 163 mV and hydrogen evolution at only 44 mV at 10 mA cm-2. It, as both an anode and a cathode, is fabricated into a cell for overall water splitting, which has an ultralow voltage value of 1.48 V to drive a current density of 10 mA cm-2 and can remain stable for at least 100 h. In the target electrode, the P element plays three important roles: (1) it can stabilize the metastable-phase structure of β-NiMoO4; (2) it can further optimize the electronic structure; and (3) it can provide more active sites. The synergistic effect for multimetal centers with different redox couples is key for the great improvement of catalytic activity. The related mechanism is discussed in detail.

Bifunctional mixed-valence ruthenium heterostructure for robust electrocatalytic water splitting in acid media

The incorporation of non-metal dopants can significantly enhance catalytic activity and improve stability. Furthermore, the creation of heterostructures is particularly advantageous to facilitate charge transfer and optimize electronic properties. This study presents an effective bifunctional mixed-valence Ruthenium heterostructure synthesized through a cascading process involving grinding with carbon nitride and subsequent thermal treatment. The catalyst exhibits outstanding electrocatalytic performance with remarkably low overpotentials of 197 mV for the oxygen evolution reaction (OER) and 24.8 mV for the hydrogen evolution reaction (HER), respectively, with the stability exceeding 24 h at a current density of 10 mA cm⁻2 in acidic media. Additionally, when employed in an acidic oxygen water splitting (OWS) electrolyzer, the bifunctional catalyst demonstrates excellent activity, achieving an ultralow cell voltage of 1.53 V to sustain 10 mA cm⁻2. Enhanced performance is attributed to efficient charge transfer and increased exposure of active sites, providing valuable insights for the development of effective acidic water-electrolysis catalysts for sustainable hydrogen production.

Rapid Synthesis of Carbon-Supported Ru-RuO₂ Heterostructures for Efficient Electrochemical Water Splitting.

Development of high-performance electrocatalysts for water splitting is crucial for a sustainable hydrogen economy. In this study, rapid heating of ruthenium(III) acetylacetonate by magnetic induction heating (MIH) leads to the one-step production of Ru-RuO₂/C nanocomposites composed of closely integrated Ru and RuO₂ nanoparticles. The formation of Mott-Schottky heterojunctions significantly enhances charge transfer across the Ru-RuO2 interface leading to remarkable electrocatalytic activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1m KOH. Among the series, the sample prepares at 300 A for 10 s exhibits the best performance, with an overpotential of only -31mV for HER and +240mV for OER to reach the current density of 10mA cm⁻2. Additionally, the catalyst demonstrates excellent durability, with minimal impacts of electrolyte salinity. With the sample as the bifunctional catalysts for overall water splitting, an ultralow cell voltage of 1.43V is needed to reach 10mA cm⁻2, 160mV lower than that with a commercial 20% Pt/C and RuO₂/C mixture. These results highlight the significant potential of MIH in the ultrafast synthesis of high-performance catalysts for electrochemical water splitting and sustainable hydrogen production from seawater.

Femtosecond-Laser-Ablated Porous Silver Nanowire Heater with Ultralow Driven-Voltage and Ultrafast Sensitivity for Highly Efficient Crude Oil Remedy.

The development of viscous-crude oil and water separation technology is important for overcoming pollution caused by oil spills. Although some separators responding to light, electric, and temperature have been proposed, their poor structural homogeneity and inferior controllability, together with weak capillary forces, hinder the rapid salvage of viscous crude oil. Herein, a Joule-heated hydrophobic porous oil/water separator is reported, which has advantages of low energy consumption (169.7 °C·cm2·W-1), short thermal-response time (5 s) and rapid heating rate (13 °C/s). Under an ultralow voltage of 4.5 V, crude oil could infiltrate through the separator within 5 s. COMSOL simulation reveals the thermodynamics of crude oil's unidirectional collection. Significantly, the gradient wettability originating from the asymmetrical temperature on the dual face is the dominant driving force for efficient oil/water separation. Finally, a homemade device is successfully deployed for continuous viscous oil/water separation. This work provides a new avenue for viscous oil remedy.

Self-supported Ni/NiO heterostructures with a controlled reduction protocol for enhanced industrial alkaline hydrogen evolution.

Self-supported Ni/NiO heterostructures with controllable ratios used in industrial alkaline water electrolysis (AWE) systems lead to an ultralow voltage of 1.79 V at 400 mA cm-2 for 2 weeks, ascribed to the synergic combination of abundant active sites, rapid electron/mass transfer and optimal HER kinetics.

Repeatable and renewable synthesis of nickel-iron nitrate hydroxide needle-like arrays for water electrolysis.

A sustainable approach utilizing a low-temperature molten salt strategy is employed in this study to fabricate homogeneous and dense NiFe nitrate hydroxide needle-like arrays on a NiFe foam substrate. The electrode also achieves an ultra-low voltage of 1.77 V at 100 mA cm-2 and maintains stability for more than 120 h at a current density of 100 mA cm-2, showing excellent overall water splitting (OWS) performance and stability. Notably, the molten salt strategy enables the synthesis of electrodes at a reaction temperature as low as 125 °C. Additionally, the molten salt precursor is repeatable and renewable, thus preventing waste and presenting vast potential for application.

Optimized leakage control in CMOS NAND gates: the in-triggering technique

Abstract Leakage power, now the largest contributor to integrated circuit power consumption, is rising quickly, according to the International Technology Roadmap for Semiconductors (ITRS). As CMOS (complementary metal-oxide semiconductor) technology continues to shrink to deep submicron levels, gate leakage and subthreshold have become important components that contribute to total power dissipation. To address this problem, many methods have been put forth, especially at the circuit level. In 45 nm CMOS, variability and short-channel effects limit noise margins and compromise gate delays, thereby compromising the timing closure and robustness of ultra-low voltage circuits. The resulting supply voltage guardband may reduce energy efficiency in order to achieve a reasonable production yield. Furthermore, the high leakage currents of these technologies decrease energy efficiency when idle intervals are prolonged. In this study, two designs of a novel two-input NAND gate at 45 nm CMOS technology are constructed using eight transistors (8-T). A novel circuit technique named "In-Triggering (INDEP with Bi-Triggering)" is presented in this study with the goal of lowering subthreshold leakage in digital circuits. This method is thoroughly contrasted with other leakage reduction strategies now in use, such as Base, Sleepy LECTOR, LECTOR, INDEP, and Bi-Triggering procedures. Evaluation is done using key performance measures such power-delay product (PDP), latency, subthreshold leakage power, and total power consumption. 45-nm Predictive Technology Models (PTM) with a nominal supply voltage of 1V are used in the investigation. According to our findings, the suggested In-Triggering technique outperforms the conventional NAND gate in terms of speed by 12% and significantly reduces leakage power by up to 56%. Furthermore, compared to the Base, Trig01, and INDEP NAND gates, the method offers mean power savings of 58.8%, 36.1%, and 30.7%, respectively. At supply voltages of 1V, a comprehensive comparison and verification are then conducted utilizing the several proposed and existing methodologies. The effectiveness of the In-Triggering technique in reducing leakage power in CMOS circuits is confirmed by comparing these results to the most well-known design strategies for both active operation and sleep modes.

High-Entropy Alloy Nanoflower Array Electrodes with Optimizable Reaction Pathways for Low-Voltage Hydrogen Production at Industrial-Grade Current Density.

Developing sufficiently effective non-precious metal catalysts for large-current-density hydrogen production is highly significant but challenging, especially in low-voltage hydrogen production systems. Here, we innovatively report high-entropy alloy nanoflower array (HEANFA) electrodes with optimizable reaction pathways for hydrazine oxidation-assisted hydrogen production at industrial-grade current densities. Atomic-resolution structural analyses confirm the single-phase solid-solution structure of HEANFA. The HEANFA electrodes exhibit the top-level electrocatalytic performance for both the alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR). Furthermore, the hydrazine oxidation-assisted splitting (OHzS) system assembled with HEANFA as both anode and cathode exhibits a record-breaking performance for hydrogen production. It achieves ultralow working voltages of 0.003, 0.081, 0.260, 0.376, and 0.646V for current densities of 10, 100, 500, 1000, and 2000mA cm-2, respectively, and remarkable stability for 300h, significantly outperforming those of previously reported OHzS systems and other chemicals-assisted hydrogen production systems. Theoretical calculations reveal that extraordinary performance of HEANFA for OHzS is attributed to its abundant high-activity sites and optimizable reaction pathways in HER and HzOR. In particular, HEANFA enables intelligent migration of key intermediates during HzOR, thereby optimizing the reaction pathways and creating high-activity sites, ultimately endowing the extraordinary performance for OHzS.

Ultralow Voltage High-Performance Nanocellulose-Based Electro-Ionic Actuators for Soft Robots.

High-performance eco-friendly soft actuators showing large displacement, fast response, and long-term operational capability require further development for next-generation bioinspired soft robots. Herein, we report an electro-ionic soft actuator based on carboxylated cellulose nanocrystals (CCNC) and carboxylated cellulose nanofibers (CCNF), graphene nanoplatelets (GN), and ionic liquid (IL). The actuator exhibited exceptional actuation performances, achieving large displacements ranging from 1.6 to 12.3 mm under ultralow actuation voltages of 0.25-1.5 V. It also operated stably across a broad frequency band from 0.1 to 10 Hz and displayed a significant working stability of 99.3% after up to 240 cycles. Remarkably, the electro-active actuator demonstrated a fast response (0.39 s delay under 1.0 V at 0.1 Hz), and a long lifespan (with only a minor decrease of 2% for 2 years). The enhanced actuation performances of the actuator were attributed to its superior ionic conductivity, high charge storage ability, strong ionic interaction, and physical-chemical cross-linked networks. Furthermore, we successfully demonstrated the bioinspired applications of CCNC/CCNF-IL-GN actuators including micro-grippers, spiral-structure electroactive stents, biomimetic fingers, and bionic dragonfly wings. The proposed actuator and its bioinspired robot designs could offer a significant way for the development of next-generation eco-friendly soft actuators, soft robots, and biomedical microdevices in microenvironments requiring low-voltage environment.

3D-Printed Hierarchical Nanostructured N-Co2NiO4 NF Electrode for Efficient Concurrent Electrocatalytic Production of Hydrogen and Formate.

Replacing the oxygen evolution reaction with the alternative glycerol electro-oxidation reaction (GER) provides a promising strategy to enhance the efficiency of hydrogen production via water electrolysis while co-generating high-value chemicals. However, obtaining low-cost and efficient GER electrocatalysts remains a big challenge. Herein, a self-supported N-doped Co2NiO4 nanoflakes (N-Co2NiO4 NF) is proposed for efficient electrocatalytic oxidation of glycerol to formate. The synergistic effect induced by the interaction of the layered Co2NiO4 nanostructures on the 3D-printed Nickel-Yttria-stabilized zirconia (Ni-YSZ) substrate and the amorphous nitrogen-doping promotes the anodic GER. The N-Co2NiO4 NF exhibits low potentials of 1.07 and 1.18V (vs. RHE) for GER to drive 10 and 50mAcm-2, respectively. The constituted two-electrode electrolyzer (N-Co2NiO4 NF//NiS-Co-NiP) displays excellent activity that only requires ultralow cell voltages of 1.24 and 1.55V to afford 10 and 200mAcm-2, respectively, with a high FE (97%) for formate production and an excellent durability (120h). This study provides a versatile approach for manufacturing high-performance Ni-based electrocatalyst for GER, paving the way for the energy-saving and environmentally-friendly co-production of value-added chemicals and hydrogen.

A Multi-Functional Molecule for Highly Durable, Bending-Resistant, Low-Voltage Driving PSLC Films toward Smart Windows With Radiative Cooling.

Polymer-stabilized liquid crystals (PSLCs) are widely used in smart windows, light modulators, and dimmed glass. However, their low mechanical strength, unsatisfactory electro-optical properties, and poor durability limit their large-scale application. In this study, a PSLC film with outstanding performance is prepared by incorporating a multifunctional molecule into a fine-sculptured liquid crystal/polymer composite. The multifunctional molecule is designed to form a vertically oriented layer with a silane coupling agent through a two-step self-assembly process and improve the mechanical strength of PSLCs by connecting the polymer networks through covalent bonds. In addition, it endowed the film with good thermal stability through the reversible change from hydrogen bonds at low temperatures to C═N bonds at high temperatures. A PSLC film with ultralow saturation voltage (Vsat <25V), wide operating temperature and viewing angle performance, high mechanical strength (60-100% improvement), and high stability (15000 cycles) is prepared through the self-assembly of the multifunctional molecule followed by photomask-assisted photopolymerization. Finally, a bending-resistant, flexible PSLC film with passive radiative cooling capacity is tested and achieved excellent temperature management. This composite film demonstrated superior performance in every aspect, promoting the application of PSLCs in smart windows for cars and buildings.

Mxene and GaIn Alloy Nanostructures Regulate Zn Surface Ion Deposition for High-Performance Zinc-Ion Battery.

Zinc is an ideal energy storage material because of its low toxicity, nonflammability, and good biocompatibility. However, the commercial application is seriously hindered due to problems such as dendrite growth, hydrogen evolution, and interface passivation caused by "dead zinc" in the process of cyclic deposition. Herein, a nanoscale deposition dispersion model is designed in order to achieve directional deposition and uniform distribution of zinc ions for the growth of interfacial dendrites. Liquid metal GaIn was combined with Mxene for this nanostructure, which provides a rapid ion transfer channel to achieve lower overpotentials, a more uniform electric field distribution, and stronger corrosion resistance in a core-shell structure to achieve interface reaction suppression. The material was coated on the surface of the zinc metal as an artificial protective layer. It has a better cycle life at 1 mA·cm-2 compared with the bare Zn metal anode, achieving a long cycle time of 1100 h and an ultralow voltage lag (28.1 mV). It maintains the stability for 1000 cycles at 1 mA·cm-2 after assembling the complete battery. This provides a way to improve the performance of zinc-ion secondary batteries and paves the way for the next generation of energy storage devices.

Deciphering the surface electrochemical reconstruction of ruthenium-cobalt-nickel phosphide for efficient high-current hydrogen evolution and overall water splitting.

Development of efficient and stable bifunctional transition metal phosphide catalysts is critical for advancing hydrogen production technologies. Herein, RuCo co-doped Ni8P3 (RuCoNiP) was designed and synthesized by one-step electrodeposition for Ni electronic structure modulation, and evolved to RuCoNiP@α-Ni(OH)2 and RuCoNiP@Co/Ni(OH)x heterointerfaces by self-assembled reconstruction during HER and OER processes, respectively. RuCoNiP@α-Ni(OH)2 enhances HER activity (305.8mV@-1000mAcm-2) and stability (100h@-1000mAcm-2) by weakening OH* and H* competitive adsorption. Density functional theory (DFT) calculations revel that the ΔGH* of Ni site (RuCoNiP) is reduced by the assignment of a large number of Ni d-states at the Fermi level by RuCo doping, which synergistically interacts with the enhanced adsorption of α-Ni(OH)2 to OH*, resulting in a lower energy barrier for hydrogen adsorption-desorption. Moreover, RuCoNiP@Co/Ni(OH)x relies on M(OH)x to enhance the activity (351.4mV@1000mAcm-2) and stability (100h@1000mAcm-2) of OER. Dual-electrode system RuCoNiP@α-Ni(OH)2//RuCoNiP@Co/Ni(OH)x demonstrates an ultra-low battery voltage (1.95V@1000mAcm-2) and excellent stability (50h@1000mAcm-2). This efficient synthetic strategy and the self-assembled heterojunction structure offer a promising path for developing efficient overall water-splitting catalysts.

Short Communication: Ultralow Voltage Electrokinetic Particle Trapping in DC-iEK Devices Using 9V Alkaline Batteries as Power Supply.

This contribution describes direct current insulator-based electrokinetic (DC-iEK) microfluidic devices stimulated by 9V alkaline batteries for the trapping of 2-µm diameter fluorescent polystyrene particles. These devices featured two triangular insulating posts within the fluidic channel. Particle trapping was clearly observed at 18V (two 9V batteries connected in series), but only intermittent particle trapping was observed with a single 9V battery. Particle trapping was determined by measuring the increase in relative fluorescence intensity at the gap region between the single pair of triangular posts. Results demonstrate that the use of low stimulating voltages (deemed as ultralow) in DC-iEK systems may be more suitable for accurate and precise electrokinetic characterization of particles-by exhibiting a very well-localized trapping region with negligible particle oscillations therein, respectively-than for high-performance and high-throughput particle manipulation (i.e., concentration, separation, filtering, or isolation).

Facile Hydrothermal Synthesis and Resistive Switching Mechanism of the α-Fe2O3 Memristor.

Among the transition metal oxides, hematite (α-Fe2O3) has been widely used in the preparation of memristors because of its excellent physical and chemical properties. In this paper, α-Fe2O3 nanowire arrays with a preferred orientation along the [110] direction were prepared by a facile hydrothermal method and annealing treatment on the FTO substrate, and then α-Fe2O3 nanowire array-based Au/α-Fe2O3/FTO memristors were obtained by plating the Au electrodes on the as-prepared α-Fe2O3 nanowire arrays. The as-prepared α-Fe2O3 nanowire array-based Au/α-Fe2O3/FTO memristors have demonstrated stable nonvolatile bipolar resistive switching behaviors with a high resistive switching ratio of about two orders of magnitude, good resistance retention (up to 103 s), and ultralow set voltage (Vset = +2.63 V) and reset voltage (Vreset = -2 V). In addition, the space charge-limited conduction (SCLC) mechanism has been proposed to be in the high resistance state, and the formation and destruction of the conductive channels modulated by oxygen vacancies have been suggested to be responsible for the nonvolatile resistive switching behaviors of the Au/α-Fe2O3/FTO memristors. Our results show the potential of the Au/α-Fe2O3/FTO memristors in nonvolatile memory applications.

(Invited) Integration and Optimization of 2D Transition Metal Dichalcogenides as Switching Layers in Memristors

Memristive devices possess the ability to dynamically adjust resistance based on previous voltage and current inputs. They represent a frontier in next-generation computational hardware, offering unparalleled potential for brain-inspired computing and neuromorphic engineering. Among the various configurations, electrochemical metallization (ECM) memristors feature a solid electrolyte layer sandwiched between two electrodes and perform resistive switching via filament formation (SET) and dissolution (RESET) [1]. Recent studies have focused on the integration of two-dimensional (2D) materials into the design of ECM memristors, aiming at improving performance and unlocking new functionalities [2-4]. 2D transition metal dichalcogenides and hexagonal boron nitride, in particular, are promising candidates for realizing memristors with ultra-low switching voltages, suitable for neuromorphic computing and artificial synapses [5, 6].In this talk, I will focus on vertical ECM memristor in crossbar configuration using chemical vapor deposited (CVD), atomic-thick MoSe2 as switching material, and Au/Cu as bottom/top electrodes. The devices exhibit nonvolatility and bipolar resistive switching behavior, with well-defined SET/RESET voltages (below 1V in absolute value) [7]. We performed atomic-scale investigations by transmission electron microscopy to unveil the filament formation mechanism within the MoSe2 layer. Our results shed light on the Cu/MoSe2 interface, particularly critical for memristor performance, providing key information on the intermixing and diffusion mechanisms of Cu atoms within the device structure.Furthermore, we studied the effect of XeF2 fluorination of the MoSe2 films to tune their surface properties and improve the ion transport kinetics across the interface with Cu. By carefully controlling the XeF2 process, we were able to induce structural and chemical modifications in the MoSe2, such as layer thinning and doping/implantation. This could provide a way of controlling the interface morphology and ultimately the performance and reliability of the memristive devices. Transport properties and X-ray photoelectron spectroscopy analyses provided insights into the fluorination-induced modifications on the MoSe2 surface, offering a framework for performance optimization. Overall, these findings rationalize the 2D materials-based ECM memristor operation and highlight the potential for advanced applications.

Evaluation of Corrosion Resistance of Au-Plated Titanium Bipolar Plates for Polymer Electrolyte Membrane Water Electrolysis

Polymer Electrolyte Membrane Water Electrolysis (PEMWE) is one of the most promising on-site hydrogen production methods using renewable energy because of its fast start-up and higher current density compared to alkaline water electrolysis (AWE). The urgent issues related to the widespread use of PEMWE are cost reduction of components and durability. Currently, titanium (Ti) is the most common material for bipolar plates for PEMWE and is coated with gold (Au) or platinum (Pt) to reduce contact resistance and improve corrosion resistance. Therefore, it is a very expensive component, accounting for about 50% of the PEMWE stack cost. Optimizing the amount of noble metal used in the coating is one way to reduce the cost of bipolar plates. In this study, the corrosion resistance and contact resistance of Ti bipolar plates with different Au plating thicknesses are compared to determine the optimal amount of Au used in coatings for bipolar plates.Commercial pure Ti plate (Ti 99.5%) was used as a test specimen. The Ti plate with 0.1 mm thickness was machined into a rectangular shape (20 mm x 50 mm) and electroplated with Au of different thicknesses (plating thickness: 0, 0.1, 0.3, 1.0 μm). The corrosion resistance of Au-plated Ti bipolar plates was evaluated by potentiostatic polarization at 2.0 V (vs. RHE) for 24 hours in a sulfuric acid solution (H2SO4, pH 3.0) at 353 K simulating the PEMWE anode environment. After the polarization test, the concentration of Ti in the test solution was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The contact resistance was measured according to the four-terminal method between Au-plated Ti bipolar plates and the porous transport layer (PTL) before and after the potentiostatic polarization test. Pt-plated titanium sintered fiber (2GDL-06N-030-PT05, Becart Co. Ltd.) with a Pt-plating thickness of 0.5 μm was used as the PTL. The surfaces of the specimens before and after the potentiostatic polarization were observed using the Ultra-Low Voltage Scanning Electron Microscope (ULV-SEM) to calculate the coverage of Au plating. Elemental qualitative analysis of the specimen surfaces was also carried out by Energy Dispersive X-ray Spectroscopy (EDX).The Ti concentration determined by ICP-MS after the potentiostatic polarization test was 4 μg dm-3 for the unplated Ti and 2 μg dm-3 for the Au plated-Ti (0.1 μm), while it was below the limit of quantification (<1 μg dm-3) when the Au plating thickness was 0.3 μm or higher. The contact resistance of unplated Ti increased by 22.0 mΩ cm2 at 2.0 MPa after polarization. On the other hand, the increase in contact resistance of Au-plated Ti was less than 0.1 mΩ cm2, regardless of the Au-plating thickness. Fig.1 shows SEM images (a) and EDX spectra (b)-(c) of the surface of the Au-plated Ti(0.1 μm) after polarization. It can be seen that there is a plating defect with a diameter of about 1 μm on the surface. EDX analysis results revealed that almost the entire Ti surface was coated with a straight Au plating layer, with only the defective areas of the underlying Ti exposed. The coverage of the Au-plated Ti (0.1 μm) was 99.86%, calculated from an area of 1 mm2 by binarizing the multiple backscattered electron images. The coverage of the Au-plated Ti (0.3 μm) is 99.98%, which indicates fewer plating defects than the Au-plated Ti (0.1 μm). Therefore, it is considered that the plating defects in the Au-plated Ti (0.1 μm) preferentially corroded and Ti was leached out. On the other hand, the contact resistance is almost the same regardless of the Au plating thickness or coverage and does not increase immediately provided that most the Ti surface is covered with Au plating. These results indicate that thinner Au coating with higher coverage on Ti bipolar plates for PEMWE can reduce the amount of Au used in the coating. Figure 1

Two-Dimensional Electrically Conductive Metal-Organic Framework Boosts Synaptic Plasticity for Dynamic Image Refresh, Classification, and Efferent Neuromuscular Systems.

We present a two-dimensional (2D) electrically conductive metal-organic framework (EC-MOF)-based artificial synapse. The intrinsic electronic conductivity and subnanometer channels of the EC-MOF facilitate efficient ion diffusion, enable a high density of active redox centers, and significantly enhance capacitance within the artificial synapse. As a result, the synapse operates at an ultralow voltage of 10 mV and exhibits a remarkably low power consumption of approximately 1 fW, along with the longest retention time recorded for two-terminal electrolyte-type artificial synapses to date. The alignment of the quantum size of the subnanometer pores in the EC-MOF with various cations allows for versatile synaptic plasticity. This capability is applied to image refresh, classification, and efferent signal transmission for controlling artificial muscles, thereby offering a methodology for achieving tunable neuromorphic properties. These findings suggest the potential application of metal-organic frameworks in artificial nervous systems for future brain-inspired computation, peripheral interfaces, and neurorobotics.

Controlled synthesis of Mn\\M-doped NiP3/Cu3P (M=Cr, Ce, Bi and Co) as electrocatalysts for urea splitting reactions in alkaline solutions

Urea is generally used in agricultural fertilization to provide nutrients they need with the crops, however overuse of urea for fertilization can pollute the environment. Electrolysis urea is a greener way of treating urea, and in recent years electrolysis urea has been studied as a hot topic. It is mainly due to the fact that the potential of urea electrolysis is 0.37 V, which is smaller than the potential of traditional water splitting of 1.23 V. In this paper, a series of synthetic experiments were carried out by doping with the same content of Cr, Ce, Bi and Co into Mn-NiP3/Cu3P. It is found that Cr-doped Mn-NiP3/Cu3P possesses excellent electrochemical properties compared to nickel foam doped with the other three elements. At an iR compensation value of 70 %, Mn\\Cr-doped NiP3/Cu3P has strong catalytic activity and durability for urea oxidation reaction (UOR). At an ultra-low voltage of 1.352 V, the Mn\\Cr-doped NiP3/Cu3P catalyst had a catalytic current of 10 mA cm−2, a low Tafel slope (102.03 mV dec−1), a high Cdl (9.35 mF cm−2), and catalytic stability of more than 50 hours. The enhanced activity of Mn\\Cr-doped NiP3/Cu3P is attributed to rapid charge transfer, improved electrical conductivity, and increased electrochemical area. Density Functional Theory (DFT) calculations showed that synergic catalytic effect of Mn-Cr-NiP3 and Mn-Cr-Cu3P in the catalysts can effectively improve the adsorption capacity of the catalysts, this provides a new ideas of exploration for the electrolysis of urea with cheap and relatively low toxicity catalysts, which can effectively reduce the cost.

Isolated FeN3 sites anchored hierarchical porous carbon nanoboxes for hydrazine‐assisted rechargeable Zn‐CO2 batteries with ultralow charge voltage

AbstractZn‐CO2 batteries (ZCBs) are promising for CO2 conversion and electric energy release. However, the ZCBs couple the electrochemical CO2 reduction (ECO2R) with the oxygen evolution reaction and competitive hydrogen evolution reaction, which normally causes ultrahigh charge voltage and CO2 conversion efficiency attenuation, thereby resulting in ~90% total power consumption. Herein, isolated FeN3 sites encapsulated in hierarchical porous carbon nanoboxes (Fe‐HPCN, derived from the thermal activation process of ferrocene and polydopamine‐coated cubic ZIF‐8) were proposed for hydrazine‐assisted rechargeable ZCBs based on ECO2R (discharging process: CO2 + 2H+ → CO + H2O) and hydrazine oxidation reaction (HzOR, charging process: N2H4 + 4OH− → N2 + 4H2O + 4e−). The isolated FeN3 endows the HzOR with a lower overpotential and boosts the ECO2R with a 96% CO Faraday efficiency (FECO). Benefitting from the bifunctional ECO2R and HzOR catalytic activities, the homemade hydrazine‐assisted rechargeable ZCBs assembled with the Fe‐HPCN air cathode exhibited an ultralow charge voltage (decreasing by ~1.84 V), excellent CO selectivity (FECO close to 100%), and high 89% energy efficiency. In situ infrared spectroscopy confirmed that Fe‐HPCN can generate rate‐determining *N2 and *CO intermediates during HzOR and ECO2R. This paper proposes FeN3 centers for bifunctional ECO2R/HzOR performance and further presents the pioneering achievements of ECO2R and HzOR for hydrazine‐assisted rechargeable ZCBs.