Inspired by the freezing tolerance performances found in living creatures, an effect approach is presented to develop novel antifreezing polymeric organohydrogel actuators. Through construction of a bilayer hydrogel including a nonresponsive polyacrylamide (PAAm) layer and a pH-responsive polyacrylic acid (PAA) layer in the presence of a mixed solvent of water and glycerol, organohydrogel actuators that could produce various shape deformations at subzero temperatures have been achieved, and the actuating speed could be tuned by adjusting the temperature and the ratio between glycerol and water. Moreover, a series of application demonstrations including a weightlifting robot, artificial valve, and robotic arm have been displayed. In addition, by introducing the ionic compound KI into the glycerol-based organogel, flexible conductors that could perform stable sensing performance over a wide range of temperatures from -30°C to 60°C have been developed.

Rechargeable aqueous zinc ion batteries (ZIBs) are considered as one of the most promising systems for large-scale energy storage due to their merits of low cost, environmental friendliness, and high safety. The utilization of aqueous electrolyte also brings about some problems such as low energy density, fast self-discharge, and capacity fading associated with the dissolution of metals in water. To combat the issues, we utilize a freestanding vanadium oxide hydrate/carbon nanotube (V₂O₅·nH₂O/CNT) film as the cathode and probe the performance in aqueous/organic hybrid electrolytes. The corresponding structural and morphological evolution of both V₂O₅·nH₂O/CNT cathode and Zn anode in different electrolytes is explored. The integrity of electrodes and the suppression of zinc dendrites during cycles are largely improved in the hybrid electrolytes. Accordingly, the battery in hybrid electrolyte exhibits high capacities of 549 mAh g^-1 at 0.5 A g^-1 after 100 cycles and 282 mAh g^-1 at 4 A g^-1 after 1000 cycles, demonstrating an excellent energy density of 102 Wh kg^-1 at a high power of 1500 W kg^-1 based on the cathode.

In quantum theory, the retrodiction problem is not as clear as its classical counterpart because of the uncertainty principle of quantum mechanics. In classical physics, the measurement outcomes of the present state can be used directly for predicting the future events and inferring the past events which is known as retrodiction. However, as a probabilistic theory, quantum-mechanical retrodiction is a nontrivial problem that has been investigated for a long time, of which the Mean King Problem is one of the most extensively studied issues. Here, we present the first experimental test of a variant of the Mean King Problem, which has a more stringent regulation and is termed “Tracking the King.” We demonstrate that Alice, by harnessing the shared entanglement and controlled-not gate, can successfully retrodict the choice of King’s measurement without knowing any measurement outcome. Our results also provide a counterintuitive quantum communication to deliver information hidden in the choice of measurement.

Two-dimensional (2D) materials have attracted increasing interests in the last decade. The ultrathin feature of 2D materials makes them promising building blocks for next-generation electronic and optoelectronic devices. With reducing dimensionality from 3D to 2D, the inevitable defects will play more important roles in determining the properties of materials. In order to maximize the functionality of 2D materials, deep understanding and precise manipulation of the defects are indispensable. In the recent years, increasing research efforts have been made on the observation, understanding, manipulation, and control of defects in 2D materials. Here, we summarize the recent research progress of defect engineering on 2D materials. The defect engineering triggered by electron beam (e-beam), plasma, chemical treatment, and so forth is comprehensively reviewed. Firstly, e-beam irradiation-induced defect evolution, structural transformation, and novel structure fabrication are introduced. With the assistance of a high-resolution electron microscope, the dynamics of defect engineering can be visualized in situ. Subsequently, defect engineering employed to improve the performance of 2D devices by means of other methods of plasma, chemical, and ozone treatments is reviewed. At last, the challenges and opportunities of defect engineering on promoting the development of 2D materials are discussed. Through this review, we aim to build a correlation between defects and properties of 2D materials to support the design and optimization of high-performance electronic and optoelectronic devices.

The selective formation of nanomaterials in cancer cells and tumors holds great promise for cancer diagnostics and therapy. Until now, most strategies rely on a single trigger to control the formation of nanomaterials in situ. The combination of two or more triggers may provide for more sophisticated means of manipulation. In this study, we rationally designed a molecule (Comp. 1) capable of responding to two enzymes, alkaline phosphatase (ALP), and reductase. Since the A549 lung cancer cell line showed elevated levels of extracellular ALP and intracellular reductase, we demonstrated that Comp. 1 responded in a stepwise fashion to those two enzymes and displayed a tandem molecular self-assembly behavior. The selective formation of nanofibers in the mitochondria of the lung cancer cells led to the disruption of the mitochondrial membrane, resulting in an increased level of reactive oxygen species (ROS) and the release of cytochrome C (Cyt C). ROS can react with proteins, resulting in endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). This severe ER stress led to disruption of the ER, formation of vacuoles, and ultimately, apoptosis of the A549 cells. Therefore, Comp. 1 could selectively inhibit lung cancer cells in vitro and A549 xenograft tumors in vivo. Our study provides a novel strategy for the selective formation of nanomaterials in lung cancer cells, which is powerful and promising for the diagnosis and treatment of lung cancer.

Rational design of single-metal atom sites in carbon substrates by a flexible strategy is highly desired for the preparation of high-performance catalysts for metal-air batteries. In this study, biomass hydrogel reactors are utilized as structural templates to prepare carbon aerogels embedded with single iron atoms by controlled pyrolysis. The tortuous and interlaced hydrogel chains lead to the formation of abundant nanowrinkles in the porous carbon aerogels, and single iron atoms are dispersed and stabilized within the defective carbon skeletons. X-ray absorption spectroscopy measurements indicate that the iron centers are mostly involved in the coordination structure of FeN₄, with a minor fraction (ca. 1/5) in the form of FeN₃C. First-principles calculations show that the FeN{}_x sites in the Stone-Wales configurations induced by the nanowrinkles of the hierarchically porous carbon aerogels show a much lower free energy than the normal counterparts. The resulting iron and nitrogen-codoped carbon aerogels exhibit excellent and reversible oxygen electrocatalytic activity, and can be used as bifunctional cathode catalysts in rechargeable Zn-air batteries, with a performance even better than that based on commercial Pt/C and RuO₂ catalysts. Results from this study highlight the significance of structural distortions of the metal sites in carbon matrices in the design and engineering of highly active single-atom catalysts.

In the past decades, the progress of wearable and portable electronics is quite rapid, but the power supply has been a great challenge for their practical applications. Wearable power sources, especially wearable energy-harvesting devices, provide some possible solutions for this challenge. Among various wearable energy harvesters, the high-performance fabric-based triboelectric nanogenerators (TENGs) are particularly significant. In this review paper, we first introduce the fundamentals of TENGs and their four basic working modes. Then, we will discuss the material synthesis, device design, and fabrication of fabric-based TENGs. Finally, we try to give some problems that need to be solved for the further development of TENGs.

Hydrophobic/superhydrophobic materials with intrinsic water repellence are highly desirable in engineering fields including anti-icing in aerocrafts, antidrag and anticorrosion in ships, and antifog and self-cleaning in optical lenses, screen, mirrors, and windows. However, superhydrophobic material should have small surface energy (SE) and a micro/nanosurface structure which can reduce solid-liquid contact significantly. The low SE is generally found in organic materials with inferior mechanical properties that is undesirable in engineering. Intriguingly, previous theoretical calculations have predicted a negative SE for θ-alumina (θ-Al₂O₃), which inspires us to use it as a superhydrophobic material. Here, we report the experimental evidence of the small/negative SE of θ-Al₂O₃ and a θ-Al₂O₃-based superhydrophobic coating prepared by one-step scalable plasma arcing oxidation. The superhydrophobic coating has complete ceramic and desired micro/nanostructure and therefore exhibits excellent aging resistance, wear resistance, corrosion resistance, high-temperature tolerance, and burning resistance. Owing to the rarity of the small/negative SE in inorganic materials, the concept to reduce SE by θ-Al₂O₃ may foster a blowout to develop robust superhydrophobicity by complete inorganic materials.

The electrochemical nitrogen reduction reaction (NRR) provides a sustainable and alternative avenue to the Haber-Bosch process for ammonia (NH₃) synthesis. Despite the great efforts made on catalysts and electrolytes, unfortunately, current NRR suffers from low selectivity due to the overwhelming competition with the hydrogen evolution reaction (HER). Here, we present an adjusted three-phase interface to enhance nitrogen (N₂) coverage on a catalyst surface and achieve a record-high Faradic efficiency (FE) up to 97% in aqueous solution. The almost entirely suppressed HER process combined with the enhanced NRR activity, benefiting from the efficient three-interface contact line, is responsible for the excellent selectivity toward NH₃, as evidenced by the theoretical and experimental results. Our strategy also demonstrates the applicability to other catalysts that feature strong H adsorption ability, to boost the FE for NH₃ synthesis above 90% and to improve the NRR activity by engineering the catalysts.

The von Neumann bottleneck has spawned the rapid expansion of neuromorphic engineering and brain-like networks. Synapses serve as bridges for information transmission and connection in the biological nervous system. The direct implementation of neural networks may depend on novel materials and devices that mimic natural neuronal and synaptic behavior. By exploiting the interfacial effects between MoS₂ and AlOx, we demonstrate that an h-BN-encapsulated MoS₂ artificial synapse transistor can mimic the basic synaptic behaviors, including EPSC, PPF, LTP, and LTD. Efficient optoelectronic spikes enable simulation of synaptic gain, frequency, and weight plasticity. The Pavlov classical conditioning experiment was successfully simulated by electrical tuning, showing associated learning behavior. In addition, h-BN encapsulation effectively improves the environmental time stability of our devices. Our h-BN-encapsulated MoS₂ artificial synapse provides a new paradigm for hardware implementation of neuromorphic engineering.