Ultrafast Quasi-Solid-State Microwave Construction of Spongy Cobalt-Molybdenum Phosphide for Hydrogen Production Over Wide pH Range.

The developed strategies for synthesizing metal phosphides are usually cumbersome and pollute the environment. In this work, an ultrafast (30 s) quasi-solid-state microwave approach is developed to construct cobalt-molybdenum phosphide decorated with Ru (Ru/CoxP-MoP) featured porous morphology with interconnected channels. The specific nanostructure favors mass transport, such as electrolyte bubbles transfer and exposing rich active sites. Moreover, the coupling effects between metallic elements, especially the decorated Ru, also act as a pivotal role on enhancing the electrocatalytic performance. Benefiting from the effects of composition and specific nanostructure, the prepared Ru/CoxP-MoP exhibits efficient HER performance with a current density of 10 mA cm-2 achieved in 1 m KOH, 0.5 m H2SO4, seawater containing 1 m KOH and 1 m PBS, with overpotentials of 52, 59, 55, 90 mV, and coupling with good stability. This work opens a novel and fast avenue to design metal-phosphide-based nanomaterials in energy-conversion and storage fields.

Construction of Quench-Induced Ru-Doped CoNiP Hierarchical Spheres for Hydrogen Evolution at High Current Densities.

Optimizing the electronic configuration improved the electrocatalytic performance of Ru doping. However, efficiently doping Ru and ensuring its stability in the hollow hierarchical structure posed a challenge. This work innovatively utilized the huge temperature difference between calcination and ice water (0 °C) to rapidly dope Ru atoms onto the CoNiP hierarchical spheres. Notably, the Ru-anchored hierarchical spheres enhanced the active area and internal space utilization. In addition, the addition of Ru dopant optimized the electronic structure and hydrogen evolution reaction (HER) kinetics of CoNiP. Surprisingly, Ru-CoNiP only required 250 mV to generate 1 A cm-2, which was 1.5 times that of commercial Pt/C. Moreover, its activation energy (Ea) was 24.3% lower than CoNiP, further confirming that the Ru dopant reduced the energy barrier of alkaline HER. In conclusion, this work proposed a new method for promoting the doping of trace amounts of ruthenium into hierarchical spheres through quenching.

Quenching-induced anion defects and precise Ru doping on Co3O4/CoN heterostructures for efficient overall water splitting performance.

The difficulty of nitride modification is to develop simple and efficient strategies to induce defects and efficiently capture Ru atoms. With these in mind, this work innovatively constructed a Ru-Co3O4/CoN-L catalyst with abundant anion defects (oxygen vacancies (VO) and nitrogen vacancies (VN)) using the nitridation-quenching-Ru doping strategy. Surprisingly, the porous structure provided more active sites, and the VN and VO were conducive to promoting the anchoring of Ru atoms. These significantly improved the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances of the Ru-Co3O4/CoN/NF-L catalyst. The density functional theory results showed that the anion defects optimized the hydrogen adsorption capacity of the Ru active sites for the HER. Furthermore, Ru dopants and anion defects reduced the OER energy barrier of the Co-active sites, accelerating the HER and OER kinetics. This study proposes a new concept for defect construction and nitride-structure optimization.

Sulfur-Induced Electronic Optimization of N-Doped Carbon with CoP/Co2P Heterostructure by Precursor Design for Rechargeable Zinc-Air Batteries.

Heteroatom doping and heterostructure construction are the key methods to improve the performance of electrocatalysts. However, developing such catalysts remains a challenging task. Herein, we designed two comparable polymers, phytic acid/thiourea polymer (PATP) and phytic acid/urea polymer (PAUP), as precursors, which contain C, N, S/O, and P by microwave heating. To pinpoint how the introduction of sulfur would affect the electronic structure and catalytic activity, these two polymers were physically blended with CoCo-Prussian blue analogue (CoCo-PBA) and further calcination, respectively. The highly dispersed CoP/Co2P-rich interfacial catalysts anchored on the N,S-codoped or N-doped carbon support were successfully prepared (CoP/Co2P@CNS and CoP/Co2P@CN). The prepared CoP/Co2P@CNS catalyst showed good ORR properties (E1/2 = 0.856 V vs RHE) and OER properties (Ej10 = 1.54 V vs RHE), which were superior to the commercial Pt/C and RuO2 catalysts. The reversible oxygen electrode index (ΔE = Ej10 - E1/2) can reach ∼0.684 V. Meanwhile, the rechargeable zinc-air battery assembled with a CoP/Co2P@CNS catalyst as the air cathode also showed excellent performance, with a charge-discharge cycle stability of up to 900 h. DFT calculations further confirm that the introduction of S atoms can affect the electronic structure and enhance the catalytic activity of C and N atoms on carbon support.

Congenital heart disease detection by pediatric electrocardiogram based deep learning integrated with human concepts.

Early detection is critical to achieving improved treatment outcomes for child patients with congenital heart diseases (CHDs). Therefore, developing effective CHD detection techniques using low-cost and non-invasive pediatric electrocardiogram are highly desirable. We propose a deep learning approach for CHD detection, CHDdECG, which automatically extracts features from pediatric electrocardiogram and wavelet transformation characteristics, and integrates them with key human-concept features. Developed on 65,869 cases, CHDdECG achieved ROC-AUC of 0.915 and specificity of 0.881 on a real-world test set covering 12,000 cases. Additionally, on two external test sets with 7137 and 8121 cases, the overall ROC-AUC were 0.917 and 0.907 while specificities were 0.937 and 0.907. Notably, CHDdECG surpassed cardiologists in CHD detection performance comparison, and feature importance scores suggested greater influence of automatically extracted electrocardiogram features on CHD detection compared with human-concept features, implying that CHDdECG may grasp some knowledge beyond human cognition. Our study directly impacts CHD detection with pediatric electrocardiogram and demonstrates the potential of pediatric electrocardiogram for broader benefits.

Dense r-Ru/FeCoP heterointerfaces induced by a defect-assisted strategy for ultrastable alkaline overall water splitting.

Simplifying the anchoring process of Ru nanoparticles (NPs) and activating their bifunctional activity are challenges in the construction of Ru-based catalysts. In this work, FeCoP nanosheets anchored by Ru NPs (r-Ru/FeCoP) were innovatively synthesized using an oxygen defect-assisted-gas-phase phosphorization strategy. Surprisingly, the η100 values of r-Ru/FeCoP in the alkaline hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) processes were 0.8 and 0.58 times those of Pt/C and RuO2, respectively. Notably, the rich Ru NPs as HER active sites on r-Ru/FeCoP enhanced the conductivity of the catalyst and promoted the reaction kinetics for HER, while the metal atoms on the FeCoP nanosheets served as OER active sites to accelerate the desorption of O2. The synergy between the two promoted the improvement of overall water splitting efficiency. Overall, this work provides a new approach for the development of low-cost bifunctional catalysts with high Ru utilization.

Developing energy-efficient N-doping technology to controllably construct N-Ru2P@Ru nanospheres for highly efficient hydrogen evolution at an ampere-level current density.

The N-doping strategy plays a vital role in optimizing electrocatalytic performance, but it often requires high-temperatures accompanied by the emission of irritating gases, which is contrary to the concept of energy saving and environmental protection. Based on this, this work innovatively uses the quenching of waste heat and the non-equilibrium state of materials to realize controllable N-doping. Notably, N dopants stimulate metal-like electroconductivity and accelerate the alkaline HER kinetics by optimizing the electronic structure of Ru2P. Surprisingly, the hydrophilic Ru core and the N-Ru2P shell with a low HER reaction energy barrier synergistically expedite hydrogen release. As anticipated, the current density of N-Ru2P@Ru (963 mA cm-2) is 2.6-fold that of Pt/C (359 mA cm-2) at 150 mV. Overall, the novel N-doping technology greatly simplifies material preparation procedures and reduces energy consumption. Moreover, this unique N-doping strategy provides a new idea for optimizing the catalyst structure and reaction kinetics.

A cardiologist-like computer-aided interpretation framework to improve arrhythmia diagnosis from imbalanced training datasets.

Arrhythmias can pose a significant threat to cardiac health, potentially leading to serious consequences such as stroke, heart failure, cardiac arrest, shock, and sudden death. In computer-aided electrocardiogram interpretation systems, the inclusion of certain classes of arrhythmias, which we term "aggressive" or "bullying," can lead to the underdiagnosis of other "vulnerable" classes. To address this issue, a method for arrhythmia diagnosis is proposed in this study. This method combines morphological-characteristic-based waveform clustering with Bayesian theory, drawing inspiration from the diagnostic reasoning of experienced cardiologists. The proposed method achieved optimal performance in macro-recall and macro-precision through hyperparameter optimization, including spliced heartbeats and clusters. In addition, with increasing bullying by aggressive arrhythmias, our model obtained the highest average recall and the lowest average drop in recall on the nine vulnerable arrhythmias. Furthermore, the maximum cluster characteristics were found to be consistent with established arrhythmia diagnostic criteria, lending interpretability to the proposed method.

Rational Design and Controlled Synthesis of V-Doped Ni3 S2 /Nix Py Heterostructured Nanosheets for the Hydrogen Evolution Reaction.

Rational construction of high-efficiency and low-cost catalysts is one of the most promising ways to produce hydrogen but remains a huge challenge. Herein, interface engineering and heteroatom doping were used to synthesize V-doped sulfide/phosphide heterostructures on nickel foam (V-Ni3 S2 /Nix Py /NF) by phosphating treatment at low temperature. The incorporation of V can adjust the electronic structure of Ni3 S2 , expose more active sites, and protect the 3D structure of Ni foam from damage. Meanwhile, the heterogeneous interface formed between Ni3 S2 and Nix Py can provide abundant active sites and accelerate electron transfer. As a result, the V-Ni3 S2 /Nix Py /NF nanosheet catalyst exhibits outstanding activity in the hydrogen evolution reaction (HER) with an extremely low overpotential of 90 mV at a current density of 10 mA cm-2 and stable durability in alkaline solution, which exceeds those most of the previously reported Ni-based materials. This work shows that rational design by interfacial engineering and metal-atom incorporation has a significant influence for efficient hydrogen evolution.

(Ni,Co)Se@Ni(OH)2 heterojunction nanosheets as an efficient electrocatalyst for the hydrogen evolution reaction.

A heterogeneous structure formed by coupling two or more phases can reinforce the activity of active sites and expedite electron transfer, which is conducive to boosting its electrocatalytic activity. Herein, we designed nickel foam supported (NiCo2)Se@Ni(OH)2 (NCS@NH) heterojunction nanosheets by a two-step method. First of all, the NiCo2S4@Ni(OH)2 (NiCo2S4@NH) nanosheets coated on nickel foam were acquired via a hydrothermal method. In the selenization treatment that followed, NiCo2S4@NH was converted into NCS@NH heterogeneous nanosheets in which the selenide nanoparticles decorated on the surface of the Ni(OH)2 nanosheets formed heterojunction interfaces, and the heterogeneous structure could accelerate electron transfer, thus improving the catalytic activity. The Ni(OH)2 nanosheets can adequately contact the electrolyte and promote the decomposition of water. Meanwhile, the thickness of the Ni(OH)2 nanosheets gradually decreases with the increase of Co doping (1.5-2.5 mmol), consequently affecting the HER properties. Notably, when the amount of Co salt added is 2 mmol, NCS@NH exhibited superior HER properties (with a voltage of 253 mV at 100 mA cm-2) and excellent stability for 24 h.

Ni2 P Interlayer and Mn Doping Synergistically Expedite the Hydrogen Evolution Reaction Kinetics of Co2 P.

Transition metal phosphide is regarded as one of the most promising candidates to replace noble-metal hydrogen evolution reaction (HER) electrocatalysts. Nevertheless, the controllable design and synthesis of transition metal phosphide electrocatalysts with efficient and stable electrochemical performance are still very challenging. Herein, a novel hierarchical HER electrocatalyst consisting of three-dimensional (3D) coral-like Mn-doped Co2 P@an intermediate layer of Ni2 P generated in situ by phosphorization on Ni foam (MnCoP/NiP/NF) is reported. Notably, both the incorporation of Mn and introduction of the Ni2 P interlayer promote Co atoms to carry more electrons, which is beneficial to reduce the force of the Co-H bond and optimize the adsorption energy of hydrogen intermediate (|ΔGH* |), thereby making MnCoP/NiP/NF exhibit outstanding HER performance with onset overpotential and Tafel slope as low as 31.2 mV and 61 mV dec-1 , respectively, in 1 m KOH electrolyte.