Improving the platinum (Pt) mass activity for the oxygen reduction reaction (ORR) requires optimization of both the specific activity and the electrochemically active surface area (ECSA). We found ...that solution-synthesized Pt/NiO core/shell nanowires can be converted into PtNi alloy nanowires through a thermal annealing process and then transformed into jagged Pt nanowires via electrochemical dealloying. The jagged nanowires exhibit an ECSA of 118 square meters per gram of Pt and a specific activity of 11.5 milliamperes per square centimeter for ORR (at 0.9 volts versus reversible hydrogen electrode), yielding a mass activity of 13.6 amperes per milligram of Pt, nearly double previously reported best values. Reactive molecular dynamics simulations suggest that highly stressed, undercoordinated rhombus-rich surface configurations of the jagged nanowires enhance ORR activity versus more relaxed surfaces.
Reliable energy modules and higher-sensitivity, higher-density, lower-powered sensing systems are constantly required to develop wearable electronics and the Internet of Things technology. As an ...emerging technology, triboelectric nanogenerators have been potentially guiding the landscape of sustainable power units and energy-efficient sensors. However, the existing triboelectric series is primarily populated by polymers and rubbers, limiting triboelectric sensing plasticity to some extent owing to their stiff surface electronic structures. To enrich the current triboelectric group, we explore the triboelectric properties of the topological insulator nanofilm by Kelvin probe force microscopy and reveal its relatively positive electrification charging performance. Both the larger surface potential difference and the conductive surface states of the nanofilms synergistically improve the charge transfer behavior between the selected triboelectric media, endowing the topological insulator-based triboelectric nanogenerator with considerable output performance. Besides serving as a wearable power source, the ultra-compact device array demonstrates innovative system-level sensing capabilities, including precise monitoring of dynamic objects and real-time signal control at the human-machine interface. This work fills the blank between topological quantum matters and triboelectric nanogenerators and, more importantly, exploits the significant potential of topological insulator nanofilms for self-powered flexible/wearable electronics and scalable sensing technologies.
By converting ambient energy into electricity, energy harvesting is capable of at least offsetting, or even replacing, the reliance of small portable electronics on traditional power supplies, such ...as batteries. Here we demonstrate a novel and simple generator with extremely low cost for efficiently harvesting mechanical energy that is typically present in the form of vibrations and random displacements/deformation. Owing to the coupling of contact charging and electrostatic induction, electric generation was achieved with a cycled process of contact and separation between two polymer films. A detailed theory is developed for understanding the proposed mechanism. The instantaneous electric power density reached as high as 31.2 mW/cm3 at a maximum open circuit voltage of 110 V. Furthermore, the generator was successfully used without electric storage as a direct power source for pulse electrodeposition (PED) of micro/nanocrystalline silver structure. The cathodic current efficiency reached up to 86.6%. Not only does this work present a new type of generator that is featured by simple fabrication, large electric output, excellent robustness, and extremely low cost, but also extends the application of energy-harvesting technology to the field of electrochemistry with further utilizations including, but not limited to, pollutant degradation, corrosion protection, and water splitting.
Manufacturing is involved with complex job shop scheduling problems (JSP). In smart factories, edge computing supports computing resources at the edge of production in a distributed way to reduce ...response time of making production decisions. However, most works on JSP did not consider edge computing. Therefore, this paper proposes a smart manufacturing factory framework based on edge computing, and further investigates the JSP under such a framework. With recent success of some AI applications, the deep Q network (DQN), which combines deep learning and reinforcement learning, has showed its great computing power to solve complex problems. Therefore, we adjust the DQN with an edge computing framework to solve the JSP. Different from the classical DQN with only one decision, this paper extends the DQN to address the decisions of multiple edge devices. Simulation results show that the proposed method performs better than the other methods using only one dispatching rule.
Lithium-sulfur batteries can deliver significantly higher specific capacity than standard lithium ion batteries, and represent the next generation of energy storage devices for both electric vehicles ...and mobile devices. However, the lithium-sulfur technology today is plagued with numerous challenges, including poor sulfur conductivity, large volumetric expansion, severe polysulfide shuttling and low sulfur utilization, which prevent its wide-spread adoption in the energy storage industry. Here we report a freestanding three-dimensional （3D） graphene frame- work for highly efficient loading of sulfur particles and creating a high capacity sulfur cathode. Using a one-pot synthesis method, we show a mechanically robust graphene-sulfur composite can be prepared with the highest sulfur weight content （90% sulfur） reported to date, and can be directly used as the sulfur cathode without additional binders or conductive additives. The graphene-sulfur composite features a highly interconnected graphene network ensuring excellent conductivity and a 3D porous structure allowing efficient ion transport and accommodating large volume expansion. Additionally, the 3D graphene framework can also function as an effective encapsulation layer to retard the polysulfide shuttling effect, thus enabling a highly robust sulfur cathode. Electrochemical studies show that such composite can deliver a highest capacity of 969 mAh-g-1, a record high number achieved for all sulfur cathodes reported to date when normalized by the total mass of the entire electrode. Our studies demonstrate that the 3D graphene framework represents an attractive scaffold material for a high performance lithium sulfur battery cathode, and could enable exciting opportunities for ultra-high capacity energy storage applications.
A hybrid‐fiber nanogenerator comprising a ZnO nanowire array, PVDF polymer and two electrodes is presented. Depending on the bending or spreading action of the human arm, at an angle of ∼90°, the ...hybrid fiber reaches electrical outputs of ∼0.1 V and ∼10 nA cm−2. The unique structure of the hybrid fiber may inspire future research in wearable energy‐harvesting technology.
Scalable preparation of solution processable graphene and its bulk materials with high specific surface areas and designed porosities is essential for many practical applications. Herein, we report a ...scalable approach to produce aqueous dispersions of holey graphene oxide with abundant in-plane nanopores via a convenient mild defect-etching reaction and demonstrate that the holey graphene oxide can function as a versatile building block for the assembly of macrostructures including holey graphene hydrogels with a three-dimensional hierarchical porosity and holey graphene papers with a compact but porous layered structure. These holey graphene macrostructures exhibit significantly improved specific surface area and ion diffusion rate compared to the nonholey counterparts and can be directly used as binder-free supercapacitor electrodes with ultrahigh specific capacitances of 283 F/g and 234 F/cm3, excellent rate capabilities, and superior cycling stabilities. Our study defines a scalable pathway to solution processable holey graphene materials and will greatly impact the applications of graphene in diverse technological areas.
Liver-expressed antimicrobial peptide-2 (LEAP-2) has mutual antagonism with ghrelin, which evokes food intake under a freely fed state. Nevertheless, the impact of LEAP-2 on ghrelin under ...time-restricted feeding (TRF), which has benefits in the context of metabolic disease, is still unknown. This study aims to explore the impact of central administration of LEAP-2 on the ingestion behavior of rats, which was evaluated using their cumulative food intake in the TRF state. Before intracerebroventricular (ICV) administration of O-n-octanoylated ghrelin (0.1 nmol/rat), as a food-stimulatory model, the rats received various doses of LEAP-2 (0.3, 1, 3 nmol/rat, ICV). Cumulative food intake was recorded at 1, 2, 4, 8, 12, and 24 h after ICV injection under 12 h freely fed and TRF states in a light phase. In 12 h freely fed and TRF states, central administration of ghrelin alone induced feeding behavior. Pre-treatment with LEAP-2 (1 and 3 nmol/rat, ICV) suppressed ghrelin-induced food intake in a dose-dependent manner in a 12 h freely fed state instead of a TRF state, which may have disturbed the balance of ghrelin and LEAP-2. This study provides neuroendocrine-based evidence that may explain why TRF sometimes fails in fighting obesity/metabolic dysfunction-associated steatotic liver disease in clinics.
Hyperuricemia has been associated with chronic kidney disease (CKD) progression. The antihyperuricemic febuxostat's potential renoprotective effect has been demonstrated in stage 1–3 CKD. Large‐scale ...studies comparing the renoprotective potential of febuxostat and allopurinol in advanced CKD are lacking. We exclusively selected 6,057 eligible patients with predialysis stage 5 CKD prescribed either febuxostat or allopurinol using the National Health Insurance Research Database in Taiwan during 2012–2015. There were 69.57% of allopurinol users and 42.01% febuxostat users who required long‐term dialysis (P < 0.0001). The adjusted hazard ratio (HR) of 0.65 (95% confidence interval (CI) 0.60–0.70) indicated near 35% lower hazards of long‐term dialysis with febuxostat use. The renal benefit of febuxostat was consistent across most patient subgroups and/or using the propensity score‐matched cohort. The adjusted HR was 0.66 (95% CI, 0.61–0.70) for long‐term dialysis or death. In conclusion, lower risk of progression to dialysis was observed in predialysis stage 5 CKD febuxostat users without compromising survival.
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