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Single-atom catalysts are becoming increasingly significant to numerous energy conversion reactions. However, their rational design and construction remain quite challenging due to the poorly understood structure–function relationship. Here we demonstrate the dynamic behavior of CuN 2 C 2 site during operando oxygen reduction reaction, revealing a substrate-strain tuned geometry distortion of active sites and its correlation with the activity. Our best CuN 2 C 2 site, on carbon nanotube with 8 nm diameter, delivers a sixfold activity promotion relative to graphene. Density functional theory and X-ray absorption spectroscopy reveal that reasonable substrate strain allows the optimized distortion, where Cu bonds strongly with the oxygen species while maintaining intimate coordination with C/N atoms. The optimized distortion facilitates the electron transfer from Cu to the adsorbed O, greatly boosting the oxygen reduction activity. This work uncovers the structure–function relationship of single-atom catalysts in terms of carbon substrate, and provides guidance to their future design and activity promotion. The rational design of single-atom catalysts is challenging. This work reveals a substrate-strain tuned geometry distortion of CuN 2 C 2 single-atom site, which greatly boosts oxygen reduction activity by facilitating electron transfer to adsorbed O.

The two-electron oxygen reduction reaction in acid is highly attractive to produce H 2 O 2 , a commodity chemical vital in various industry and household scenarios, which is still hindered by the sluggish reaction kinetics. Herein, both density function theory calculation and in-situ characterization demonstrate that in dual-atom CoIn catalyst, O-affinitive In atom triggers the favorable and stable adsorption of hydroxyl, which effectively optimizes the adsorption of OOH on neighboring Co. As a result, the oxygen reduction on Co atoms shifts to two-electron pathway for efficient H 2 O 2 production in acid. The H 2 O 2 partial current density reaches 1.92 mA cm −2 at 0.65 V in the rotating ring-disk electrode test, while the H 2 O 2 production rate is as high as 9.68 mol g −1 h −1 in the three-phase flow cell. Additionally, the CoIn-N-C presents excellent stability during the long-term operation, verifying the practicability of the CoIn-N-C catalyst. This work provides inspiring insights into the rational design of active catalysts for H 2 O 2 production and other catalytic systems. The 2-electron oxygen reduction in acid is highly attractive to produce H 2 O 2 , a vital commodity chemical. Here, the authors report CoIn-N-C dual-atom catalyst for effective H 2 O2 production in acid, and show in-situ hydroxyl adsorption on In atoms is important for the selectivity alteration on nearby Co atoms.

The development of alternative clean energy carriers is a key challenge for our society. Carbon-based hydrogen storage materials are well-suited to undergo reversible (de)hydrogenation reactions and the development of catalysts for the individual process steps is crucial. In the current state, noble metal-based catalysts still dominate this field. Here, a system for partially reversible and carbon-neutral hydrogen storage and release is reported. It is based on the dual-functional roles of formamides and uses a small molecule Fe-pincer complex as the catalyst, showing good stability and reusability with high productivity. Starting from formamides, quantitative production of CO-free hydrogen is achieved at high selectivity ( > 99.9%). This system works at modest temperatures of 90 °C, which can be easily supplied by the waste heat from e.g., proton-exchange membrane fuel cells. Employing such system, we achieve >70% H 2 evolution efficiency and >99% H 2 selectivity in 10 charge-discharge cycles, avoiding undesired carbon emission between cycles. The search for new carbon-based hydrogen storage materials attracts scientists from various disciplines. Now, carbon-neutral hydrogen storage-release is reported based on dual-functional roles of formamides and uses non-noble, Fe-based catalyst.

HighlightsA thermoelectric aerogel of highly elastic, flame-retardant and high-temperature-resistant PEDOT:PSS/SWCNT composite is fabricated.The assembled thermoelectric generator generates a maximum output power of 400 μW at a temperature difference of 300 K.The self-powered wearable sensing glove can achieve wide-range temperature detection, complex hand motion recognition and high-temperature warning.The intelligent fire warning system enables highly sensitive and repeatable monitoring and alarm capabilities for high-temperature fire sources.Despite notable progress in thermoelectric (TE) materials and devices, developing TE aerogels with high-temperature resistance, superior TE performance and excellent elasticity to enable self-powered high-temperature monitoring/warning in industrial and wearable applications remains a great challenge. Herein, a highly elastic, flame-retardant and high-temperature-resistant TE aerogel, made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/single-walled carbon nanotube (PEDOT:PSS/SWCNT) composites, has been fabricated, displaying attractive compression-induced power factor enhancement. The as-fabricated sensors with the aerogel can achieve accurately pressure stimuli detection and wide temperature range monitoring. Subsequently, a flexible TE generator is assembled, consisting of 25 aerogels connected in series, capable of delivering a maximum output power of 400 μW when subjected to a temperature difference of 300 K. This demonstrates its outstanding high-temperature heat harvesting capability and promising application prospects for real-time temperature monitoring on industrial high-temperature pipelines. Moreover, the designed self-powered wearable sensing glove can realize precise wide-range temperature detection, high-temperature warning and accurate recognition of human hand gestures. The aerogel-based intelligent wearable sensing system developed for firefighters demonstrates the desired self-powered and highly sensitive high-temperature fire warning capability. Benefitting from these desirable properties, the elastic and high-temperature-resistant aerogels present various promising applications including self-powered high-temperature monitoring, industrial overheat warning, waste heat energy recycling and even wearable healthcare.

Highlights Covering the most cutting-edge advances in cement-based thermoelectric materials. The first systematic summary of the preparation, performance and functional applications of cement-based thermoelectric devices. The challenges and strategies for materials, devices and applications are fully discussed. Cement stands as a dominant contributor to global energy consumption and carbon emissions in the construction industry. With the upgrading of infrastructure and the improvement of building standards, traditional cement fails to reconcile ecological responsibility with advanced functional performance. By incorporating tailored fillers into cement matrices, the resulting composites achieve enhanced thermoelectric (TE) conversion capabilities. These materials can harness solar radiation from building envelopes and recover waste heat from indoor thermal gradients, facilitating bidirectional energy conversion. This review offers a comprehensive and timely overview of cement-based thermoelectric materials (CTEMs), integrating material design, device fabrication, and diverse applications into a holistic perspective. It summarizes recent advancements in TE performance enhancement, encompassing fillers optimization and matrices innovation. Additionally, the review consolidates fabrication strategies and performance evaluations of cement-based thermoelectric devices (CTEDs), providing detailed discussions on their roles in monitoring and protection, energy harvesting, and smart building. We also address sustainability, durability, and lifecycle considerations of CTEMs, which are essential for real-world deployment. Finally, we outline future research directions in materials design, device engineering, and scalable manufacturing to foster the practical application of CTEMs in sustainable and intelligent infrastructure.

HighlightsThe flexible single-walled carbon nanotube/titanium carbide composite films exhibit excellent thermoelectric (TE), high-temperature stable and flame-retardant properties.The assembled TE device achieves an ultrafast fire warning response time of ~ 0.1 s with a threshold voltage of 1 mV.The fire warning device demonstrates exceptional repeatability and long-term stability.The designed intelligent system is promising for next-generation self-powered remote IoT fire warning applications.Fire warning is vital to human life, economy and ecology. However, the development of effective warning systems faces great challenges of fast response, adjustable threshold and remote detecting. Here, we propose an intelligent self-powered remote IoT fire warning system, by employing single-walled carbon nanotube/titanium carbide thermoelectric composite films. The flexible films, prepared by a convenient solution mixing, display p-type characteristic with excellent high-temperature stability, flame retardancy and TE (power factor of 239.7 ± 15.8 μW m−1 K−2) performances. The comprehensive morphology and structural analyses shed light on the underlying mechanisms. And the assembled TE devices (TEDs) exhibit fast fire warning with adjustable warning threshold voltages (1–10 mV). Excitingly, an ultrafast fire warning response time of ~ 0.1 s at 1 mV threshold voltage is achieved, rivaling many state-of-the-art systems. Furthermore, TE fire warning systems reveal outstanding stability after 50 repeated cycles and desired durability even undergoing 180 days of air exposure. Finally, a TED-based wireless intelligent fire warning system has been developed by coupling an amplifier, analog-to-digital converter and Bluetooth module. By combining TE characteristics, high-temperature stability and flame retardancy with wireless IoT signal transmission, TE-based hybrid system developed here is promising for next-generation self-powered remote IoT fire warning applications.

Highlights A novel photobase generator is specifically designed for the fabrication of high-resolution sensing devices. Similarities in pain perception mechanism between thermoelectric-based artificial thermoreceptor and biological nociceptor. Emulation common nociceptive behaviors and pain response under excessive temperature stimuli. The development of bionic sensing devices with advanced physiological functionalities has attracted significant attention in flexible electronics. In this study, we innovatively develop an air-stable photo-induced n -type dopant and a sophisticated photo-induced patterning technology to construct high-resolution joint-free p – n integrated thermoelectric devices. The exceptional stability of the photo-induced n -type dopant, combined with our meticulously engineered joint-free device architecture, results in extremely low temporal and spatial variations. These minimized variations, coupled with superior linearity, position our devices as viable candidates for artificial thermoreceptors capable of sensing external thermal noxious stimuli. By integrating them into a robotic arm with a pain perception system, we demonstrate accurate pain responses to external thermal stimuli. The system accurately discerns pain levels and initiates appropriate protective actions across varying intensities. Our findings present a novel strategy for constructing high-resolution thermoelectric sensing devices toward precise biomimetic thermoreceptors.

HighlightsThe MXene-boosted rapid gelling expedites the assembly of flexible thermocell arrays, overcoming the typical constraint of complicated device fabrication processes.The hydrogel electrolyte can sustain stable thermoelectrochemical performance under various challenging conditions, including large, repeated, and sustained deformations, and multiple cut-healing cycles.The as-assembled thermocell array exhibits device-level self-healing capability and high adaptability to human body, efficiently harvesting low-grade heat for wearable applications.The evolution of wearable technology has prompted the need for adaptive, self-healable, and energy-autonomous energy devices. This study innovatively addresses this challenge by introducing an MXene-boosted hydrogel electrolyte, which expedites the assembly process of flexible thermocell (TEC) arrays and thus circumvents the complicated fabrication of typical wearable electronics. Our findings underscore the hydrogel electrolyte's superior thermoelectrochemical performance under substantial deformations and repeated self-healing cycles. The resulting hydrogel-based TEC yields a maximum power output of 1032.1 nW under the ΔT of 20 K when being stretched to 500% for 1000 cycles, corresponding to 80% of its initial state; meanwhile, it sustains 1179.1 nW under the ΔT of 20 K even after 60 cut-healing cycles, approximately 92% of its initial state. The as-assembled TEC array exhibits device-level self-healing capability and high adaptability to human body. It is readily applied for touch-based encrypted communication where distinct voltage signals can be converted into alphabet letters; it is also employed as a self-powered sensor to in-situ monitor a variety of body motions for complex human actions. The swift assembly approach, combined with the versatile functionality of the TEC device, paves the way for future advancements in wearable electronics targeting at fitness monitoring and human–machine interfaces.

This study focuses on designing and optimizing Permanent Magnet Synchronous Motors (PMSMs) using hybrid rare earth and ferrite materials. Two distinctive rotor topologies of the Hybrid-Type Permanent Magnet Motor (HTPMM) are proposed: series and parallel magnetic circuits. Initially, the rotor topology and magnetic circuit principles of both the prototype and the designed HTPMM are introduced. Subsequently, a multi-objective genetic algorithm is employed to optimize the two HTPMMs, determining the final optimized parameters. Thise study further analyzes the cost advantage of HTPMMs from the perspective of permanent magnet materials, and detailed finite element analysis is conducted to evaluate the electromagnetic performance, including the air-gap flux density, no-load back electromotive force, cogging torque, load torque characteristics, and demagnetization properties. A comparative analysis of the prototype and two designed motors reveals that the HTPMM exhibits similar performance to the prototype, effectively reducing the usage of rare earth materials and significantly lowering the manufacturing costs. This research validates the feasibility of reducing rare earth material usage while maintaining a similar performance and provides a new perspective for the design of permanent magnet motors.

The cylinder linear induction motor (CLIM) is a variation of the rotary induction motor. Its structure is simple, it has a low manufacturing cost, and it can generate linear thrust without the need for a conversion mechanism. It is particularly suitable for electromagnetic catapults, magnetic levitation transport, and industrial production fields, due to its strong environmental adaptability. Designing a high-thrust and high-efficiency CLIM is a great challenge due to its inherent drawbacks, such as the low thrust density and power density of induction motors. In this article, two CLIMs with different topologies are proposed to meet the demand for control-rod drives in high-temperature and high-pressure environments. The article elucidates the topologies of the two CLIMs and proposes an analytical computational approach for the CLIM. Modern optimization algorithms were utilized to optimize the design of the structural parameters of both CLIMs. A 3D-FEA simulation was used to compare and analyze the air-gap magnetism and thrust characteristics of two CLIMs. The results indicate that the copper-ring secondary CLIM has a higher thrust density and is more suitable for use in control-rod drive mechanism (CRDM) systems.