Facilitating alkaline hydrogen evolution reaction on the hetero-interfaced Ru/RuO2 through Pt single atoms doping.

Exploring an active and cost-effective electrocatalyst alternative to carbon-supported platinum nanoparticles for alkaline hydrogen evolution reaction (HER) have remained elusive to date. Here, we report a catalyst based on platinum single atoms (SAs) doped into the hetero-interfaced Ru/RuO2 support (referred to as Pt-Ru/RuO2), which features a low HER overpotential, an excellent stability and a distinctly enhanced cost-based activity compared to commercial Pt/C and Ru/C in 1 M KOH. Advanced physico-chemical characterizations disclose that the sluggish water dissociation is accelerated by RuO2 while Pt SAs and the metallic Ru facilitate the subsequent H* combination. Theoretical calculations correlate with the experimental findings. Furthermore, Pt-Ru/RuO2 only requires 1.90 V to reach 1 A cm-2 and delivers a high price activity in the anion exchange membrane water electrolyzer, outperforming the benchmark Pt/C. This research offers a feasible guidance for developing the noble metal-based catalysts with high performance and low cost toward practical H2 production.

FedEYE: A scalable and flexible end-to-end federated learning platform for ophthalmology.

Data-driven machine learning, as a promising approach, possesses the capability to build high-quality, exact, and robust models from ophthalmic medical data. Ophthalmic medical data, however, presently exist across disparate data silos with privacy limitations, making centralized training challenging. While ophthalmologists may not specialize in machine learning and artificial intelligence (AI), considerable impediments arise in the associated realm of research. To address these issues, we design and develop FedEYE, a scalable and flexible end-to-end ophthalmic federated learning platform. During FedEYE design, we adhere to four fundamental design principles, ensuring that ophthalmologists can effortlessly create independent and federated AI research tasks. Benefiting from the design principles and architecture of FedEYE, it encloses numerous key features, including rich and customizable capabilities, separation of concerns, scalability, and flexible deployment. We also validated the applicability of FedEYE by employing several prevalent neural networks on ophthalmic disease image classification tasks.

Rapid determination of neomycin in biological samples using fluorescent sensor based on quantum dots with doubly selective binding sites.

A new analytical method was developed to detect neomycin in complex biological samples using molecularly imprinted polymer to construct an optical sensor. Fluorescent neomycin-imprinted polymers (fMIPs) containing both imprinted cavity and boronate affinity site were synthesized on the surface of silica-modified quantum dots. The fMIPs exhibited high selectivity to neomycin by having two binding sites for the target analyte. Neomycin analogues (competing for imprinted cavity) and D-glucose (competing for the boronate affinity site) did not affect the selectivity of the fMIPs. When combined with a fluorescent microplate reader, the obtained fMIP sensor displayed a linear concentration-dependent fluorescence quenching in response to neomycin in the range of 2-1000 µg/L, with a limit of detection as 0.16 µg/L. The fMIP sensor was able to detect trace neomycin in biological samples accurately after simple sample pre-treatment. The sensitivity of the fMIP sensor was higher than HPLC equipped with a fluorescence detector. The fMIP sensor containing the doubly selective binding sites provides a selective, sensitive, accurate, and high through-put approach for neomycin monitoring.

Performance optimization of LSCF/Gd:CeO2 composite cathodes via single-step inkjet printing infiltration.

ABSTRACT: The effect of solid oxide fuel cell cathode microstructure modification on its electrochemical activity is investigated. Inkjet printing infiltration was used to develop a nano-decoration pattern on the composite cathode scaffolds. Two types of composite La0.6Sr0.4Co0.2Fe0.8O3-δ:Ce0.9Gd0.1O1.9 cathodes with different volume ratios (60:40 and 40:60 vol%) were fabricated using inkjet printing of suspension inks. The electrodes were altered by single-step inkjet printing infiltration of ethanol-based Ce0.9Gd0.1O1.9 ink. After heat treatments in air at 550 °C the cathodes' surfaces were shown to be nano-decorated with Ce0.9Gd0.1O1.9 particles (~20-120 nm in size) dispersed uniformly onto the electrode scaffold. The nano-engineered microstructure enhanced the active triple phase boundary of the electrode and promoted the surface exchange reaction of oxygen. Electrochemical impedance tests conducted on symmetrical cells showed a reduction in the polarization resistance of between 1.3 and 2.9 times. The effect was found to be more pronounced in the 60:40 vol% composite cathodes. Ageing of infiltrated electrodes up to 60 h in air revealed enhanced stability of gadolinium doped ceria nanoparticles decorated electrodes ascribed to the suppression of SrO surface segregation. This work demonstrated that single-step inkjet printing infiltration can produce reproducible performance enhancements and thus offers a cost-effective route for commercial solid oxide fuel cell infiltration processing.

Synthesis of semiconducting polymer microparticles as solid ionophore with abundant complexing sites for long-life Pb(II) sensors.

Intrinsically electrically semiconducting microparticles of semiladder poly(m-phenylenediamine-co-2-hydroxy-5-sulfonic aniline) structures containing abundant functional groups, like -NH-, -N=, -NH2, -OH, -SO3H as complexation sites, were efficiently synthesized by chemical oxidative copolymerization of m-phenylenediamine and 2-hydroxy-5-sulfonic aniline. The obtained copolymers were found to be nonporous spherical microparticles that were able to achieve greater π-conjugated structure, smaller particle aggregate size, and stronger interaction with Pb(II) ions than poly(m-phenylenediamine) containing only -NH-, -N=, and -NH2. A potentiometric Pb(II) sensor was fabricated on the basis of the copolymer microparticles as a crucial solid ionophore component within plasticized PVC. The sensor exhibited a Nernstian response to Pb(II) ions over a wide concentration range, together with a fast response, a wide pH range capability, a long lifetime of up to 5 months, and good selectivity over a wide variety of other ions and redox species. The process for synthesizing the microparticles and fabricating the Pb(II)-sensor can be facilely scaled-up for use in the straightforward long-term online monitoring of Pb(II) ions in heavily polluted wastewaters. This study develops an understanding of the facile synthesis of conducting microparticles bearing many functional groups and their structures governing the potentiometric susceptibility toward interaction between Pb(II) ions and the microparticles for fabricating robust long-lived Pb(II)-sensor, signifying the potential suitability of such novel materials for inexpensive sensitive detection of Pb(II) ions.

Binder free three-dimensional sulphur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulphur batteries.

A novel ultra-lightweight three-dimensional (3-D) cathode system for lithium sulphur (Li-S) batteries has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene (FLG) via a sulphur solution infiltration method. A free-standing FLG monolithic network foam was formed as a negative of a Ni metallic foam template by CVD followed by etching away of Ni. The FLG foam offers excellent electrical conductivity, an appropriate hierarchical pore structure for containing the electro-active sulphur and facilitates rapid electron/ion transport. This cathode system does not require any additional binding agents, conductive additives or a separate metallic current collector thus decreasing the weight of the cathode by typically ∼20-30 wt%. A Li-S battery with the sulphur-FLG foam cathode shows good electrochemical stability and high rate discharge capacity retention for up to 400 discharge/charge cycles at a high current density of 3200 mA g(-1). Even after 400 cycles the capacity decay is only ∼0.064% per cycle relative to the early (e.g. the 5th cycle) discharge capacity, while yielding an average columbic efficiency of ∼96.2%. Our results indicate the potential suitability of graphene foam for efficient, ultra-light and high-performance batteries.