Boosting Hydrogen Production by Selective Anodic Electrooxidation of Ethanol over Trimetallic PdSbBi Nanoparticles: Composition Matters.

The conventional hydrogen evolution from water electrolysis is severely impeded by the sluggish kinetics of oxygen evolution reaction (OER). In this work, an integrated electrolysis system of replacing the anodic OER with a thermodynamically favorable ethanol oxidation reaction (EOR) has been developed by using PdSbBi/C as an electrocatalyst. To maximize the EOR performance, the composition of PdSbBi nanoparticles is tuned by varying the ratio of Sb and Bi precursors. Ternary PdSbBi-based electrocatalysts exhibit enhanced activity and stability toward EOR compared to commercial Pd/C and binary catalysts. In particular, the Pd76Sb17Bi7/C catalyst delivers a very high specific activity up to 52.4 mA cm-2 and mass activity of 2.66 A mg-1Pd. Besides, this EOR process is demonstrated to have high selectivity with acetic acid as the oxidation product in the electrolyte. When coupled with a cathodic platinum mash, the two-electrode electrolyzer cell requires a voltage input of merely 0.61 V to afford a current density of 10 mA cm-2. Density functional theory calculations reveal that the presence of Sb and Bi can promote the adsorption of hydroxide ions and facilitate the removal of reaction intermediates in the EOR pathway. This work provides a novel catalyst for the energy-efficient coproduction of acetic acid and hydrogen fuel.

Molybdenum single-atoms decorated multi-channel carbon nanofibers for advanced lithium-selenium batteries.

The cathode in lithium-selenium (Li-Se) batteries has garnered extensive attention owing to its superior specific capacity and enhanced conductivity compared to sulfur. Nonetheless, the adoption and advancement of Li-Se batteries face significant challenges due to selenium's low reactivity, substantial volume fluctuations, and the shuttle effect associated with polyselenides. Single-atom catalysts (SACs) are under the spotlight for their outstanding catalytic efficiency and optimal atomic utilization. To address the challenges of selenium's low chemical activity and volume expansion in Li-Se batteries, through electrospun, we have developed a lotus root-inspired carbon nanofiber (CNF) material, featured internal multi-channels and anchored with molybdenum (Mo) single atoms (Mo@CNFs). Mo single atoms significantly enhance the conversion kinetics of selenium (Se), facilitating rapid formation of Li2Se. The internally structured multi-channel CNF serves as an effective host matrix for Se, mitigating its volume expansion during the electrochemical process. The resulting cathode, Se/Mo@CNF composite, exhibits a high discharge specific capacity, superior rate performance, and impressive cycle stability in Li-Se batteries. After 500 cycles at a current density of 1 C, it maintains a capacity retention rate of 82% and nearly 100% coulombic efficiency (CE). This research offers a new avenue for the application of single-atom materials in enhancing advanced Li-Se battery performance.

Innovative Solutions for High-Performance Silicon Anodes in Lithium-Ion Batteries: Overcoming Challenges and Real-World Applications.

Silicon (Si) has emerged as a potent anode material for lithium-ion batteries (LIBs), but faces challenges like low electrical conductivity and significant volume changes during lithiation/delithiation, leading to material pulverization and capacity degradation. Recent research on nanostructured Si aims to mitigate volume expansion and enhance electrochemical performance, yet still grapples with issues like pulverization, unstable solid electrolyte interface (SEI) growth, and interparticle resistance. This review delves into innovative strategies for optimizing Si anodes' electrochemical performance via structural engineering, focusing on the synthesis of Si/C composites, engineering multidimensional nanostructures, and applying non-carbonaceous coatings. Forming a stable SEI is vital to prevent electrolyte decomposition and enhance Li+ transport, thereby stabilizing the Si anode interface and boosting cycling Coulombic efficiency. We also examine groundbreaking advancements such as self-healing polymers and advanced prelithiation methods to improve initial Coulombic efficiency and combat capacity loss. Our review uniquely provides a detailed examination of these strategies in real-world applications, moving beyond theoretical discussions. It offers a critical analysis of these approaches in terms of performance enhancement, scalability, and commercial feasibility. In conclusion, this review presents a comprehensive view and a forward-looking perspective on designing robust, high-performance Si-based anodes the next generation of LIBs.

Boosting uniform nucleation and suppressing hydrogen evolution with an in-situ formed zinc hyaluronate protective film on zinc anodes.

Developing long-cycle stable Zn-ion batteries encounters significant challenges associated with Zn anodes. To address these issues, we propose an interface engineering strategy using an artificial protective layer called zinc hyaluronate (ZH) on the Zn anode surface. The ZH film acts as a barrier, preventing direct contact between Zn anode and electrolyte, reducing hydrogen evolution and corrosion. Its carboxyl and hydroxyl groups create uniform and plentiful nucleophilic sites for Zn2+ ions, promoting uniform Zn deposition and suppressing dendrite growth. Remarkably, a Zn//Zn symmetric cell assembled with ZH-decorated Zn foil (Zn@ZH) exhibits outstanding cycle life, lasting 3600 h at a current density of 5 mA cm-2 and a capacity density of 5 mAh cm-2, much better than cells with pristine Zn anode. Even under extremely tough conditions of 10 mA cm-2 and 10 mAh cm-2, the battery life exceeds 1300 h. Furthermore, the Zn@ZH//V2O5 full cell demonstrates superior capacity retention compared to the Zn//V2O5 cell after 1000 cycles at a current density of 10 A g-1. These results highlight the benefits of the artificial protective layer strategy for advanced Zn anodes, providing insights into the underlying mechanism and promoting the development of high-performance aqueous zinc ion batteries.

Ultrafast vibrational relaxation dynamics of carbonyl stretching modes in Os3(CO)12.

The vibrational relaxation dynamics of the four infrared active carbonyl (CO) stretching normal modes of Os(3)(CO)(12) at 2068 cm(-1), 2034 cm(-1), 2014 cm(-1), and 2002 cm(-1) were measured using broad-band frequency resolved pump-probe spectroscopy. Transient absorption spectra of these modes were collected, and the fundamental, overtone, and combination bands were assigned. The frequency resolved pump-probe traces measured at the fundamental frequencies for the four stretching normal modes exhibited marked differences: the two axial modes at frequencies of 2068 cm(-1) and 2034 cm(-1) yielded similar bi-exponential decay traces, while the two equatorial modes at 2014 cm(-1) and 2002 cm(-1) showed a rising component, in addition to a bi-exponential decay. Due to the independence of the axial and equatorial stretching modes, it is shown that the axial-equatorial combination anharmonicity constants are near zero. This results in the appearance of the pump-probe signals of these combination bands at the same frequencies as the fundamental transitions, thus leading to interference and the resultant anomalous rising features. If unaccounted for, these interferences may lead to erroneous conclusions about the dynamics of these vibrational stretches. To avoid such pitfalls, it is therefore imperative to resolve such ambiguities. A corrected dynamical picture of the equatorial modes can be obtained by varying the center frequency of the pump pulse. The four modes have a slow vibrational excited population decay time of between 400 to 600 ps. We observe no obvious direct vibrational energy transfer between the axial and equatorial CO stretching modes.

Self-assembled semiconducting polymer based hybrid nanoagents for synergistic tumor treatment.

There is an impending need for the development of carrier-free nanosystems for single laser triggered activation of phototherapy, as such approach can overcome the drawbacks associated with irradiation by two distinct laser sources for avoiding prolonged treatment time and complex treatment protocols. Herein, we developed a self-assembled nanosystem (SCP-CS) consisting of a new semiconducting polymer (SCP) and encapsulated ultrasmall CuS (CS) nanoparticles. The SCP component displays remarkable near infrared (NIR) induced photothermal ability, enhanced reactive oxygen species (ROS) generation, and incredible photoacoustic (PA) signals upon activation by 808 nm laser for phototherapy mediated cancer ablation. The CuS component improves the PA imaging ability of SCP-CS, and also enhances photo-induced chemodynamic efficacy. Attributed to promoted single laser-triggered hyperthermia and enhanced ROS generation, the SCP-CS nanosystem shows effective intracellular uptake and intratumoral accumulation, enhanced tumor suppression with reduced treatment time, and devoid of any noticeable toxicity.

Mid-infrared polarization pulse shaping by parametric transfer.

We demonstrate the generation of arbitrary amplitude, phase, and polarization controlled pulses in the mid-infrared (MIR) tunable around 3.5 microm. Two temporally separated sets of individually phase and amplitude shaped pulse profiles in the near-infrared are transferred into the MIR via two independent optical parametric amplification processes in two perpendicularly oriented nonlinear crystals in a common-path geometry. The resulting two shaped MIR light fields of orthogonal polarizations are temporally recombined interferometrically in a birefringent material.

Clinical Features of Combined Central Retinal Artery and Vein Occlusion.

PURPOSE: To describe the clinical features of combined central retinal artery and vein occlusion (CCRAVO). METHODS: This retrospective study included 33 admitted patients (33 eyes) who had CCRAVO. Clinical data, such as age, gender, best-corrected visual acuity (BCVA), intraocular pressure (IOP), findings on fundus color photography and fundus fluorescein angiography (FFA), and information about follow-up, were collected and analyzed. RESULTS: The age of the patients with CCRAVO ranged from 22 to 78 years, with a mean of 48.8 ± 14.1 years. At presentation, BCVA of the involved eyes ranged from no light perception (NLP) to 20/20. In addition, 45.5% (15/33) of the eyes had BCVA of finger counting (FC) or below, whereas 12.1% (4/33) had BCVA of 20/60 or above. The IOP was lower in the involved eyes than in the fellow eyes (15.0 ± 3.0 mmHg vs. 16.4 ± 2.3 mmHg, p=0.03). Ophthalmoscopic examination showed changes in both central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO), including retinal hemorrhage, retinal ischemic whitening, optic disc hyperemia and/or edema, venous dilation and tortuosity, cotton wool spot (CWS), and Roth's spot. FFA showed prolonged arm-to-retina time (ART) and retinal arteriovenous passage time (RAP) (17.1 ± 4.9 s and 12.1 ± 8.8 s, respectively). Capillary nonperfusion (CNP) was seen in 21 eyes (63.6%), and in 14 (42.2%) of these, CNP was larger than 10 disc areas. At 2 to 3 weeks after presentation, BCVA improved in 23 eyes (71.9%) and further deteriorated in 5 eyes (15.6%). Retinal ischemic whitening improved in more than half of the eyes, whereas retinal hemorrhage increased in nearly half of the eyes. Follow-up ranged from 6 to 56 months. Seven patients were lost to follow-up. At final follow-up, six eyes had a visual acuity of 20/60 or greater, but 6 eyes had FC or worse. Four eyes developed neovascularization on follow-up. CONCLUSION: CCRAVO is a sight-threatening entity. Manifestations of CRAO and CRVO can be seen simultaneously in the early stage of disease, and CRVO may play a more important role in the development of CCRAVO.

Cooperative singlet and triplet exciton transport in tetracene crystals visualized by ultrafast microscopy.

Singlet fission presents an attractive solution to overcome the Shockley-Queisser limit by generating two triplet excitons from one singlet exciton. However, although triplet excitons are long-lived, their transport occurs through a Dexter transfer, making them slower than singlet excitons, which travel by means of a Förster mechanism. A thorough understanding of the interplay between singlet fission and exciton transport is therefore necessary to assess the potential and challenges of singlet-fission utilization. Here, we report a direct visualization of exciton transport in single tetracene crystals using transient absorption microscopy with 200 fs time resolution and 50 nm spatial precision. These measurements reveal a new singlet-mediated transport mechanism for triplets, which leads to an enhancement in effective triplet exciton diffusion of more than one order of magnitude on picosecond to nanosecond timescales. These results establish that there are optimal energetics of singlet and triplet excitons that benefit both singlet fission and exciton diffusion.