Ostwald-Ripening Induced Interfacial Protection Layer Boosts 1,000,000-Cycled Hydronium-Ion Battery.

Collapsing and degradation of active materials caused by the electrode/electrolyte interface instability in aqueous batteries are one of the main obstacles that mitigate the capacity. Herein by reversing the notorious side reactions include the loss and dissolution of electrode materials: as we applied Ostwald ripening (OR) in the electrochemical cycling of a copper hexacyanoferrate electrode in a hydronium-ion batteries, the dissolved Cu and Fe ions undergo a crystallization process that creates a stable interface layer of cross-linked cubes on the electrode surface. The layer exposed the low-index crystal planes (100) and (110) through OR-induced electrode particle growth, supplemented by vacancy-ordered (100) superlattices that facilitated ion migration. Our design stabilized the electrode-electrolyte interface considerably, achieving a cycle life of one million cycles with capacity retention of 91.6%, and a capacity retention of 91.7% after 3000 cycles for a full battery.

Rapid and simultaneous multiple detection of a tripledemic using a dual-gate oxide semiconductor thin-film transistor-based immunosensor.

The simultaneous infection with a tripledemic-simultaneous infection with influenza A pH1N1 virus (Flu), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV)-necessitates the development of accurate and fast multiplex diagnostic tests. The coronavirus disease 2019 (COVID-19) pandemic has emphasized the importance of virus detection. Field-effect transistor (FET)-based immuno-biosensors have a short detection time and do not require labeling or polymerase chain reaction. This study demonstrates the rapid, sensitive detection of influenza A pH1N1, SARS-CoV-2, and RSV using a multiplex immunosensor based on a dual-gate oxide semiconductor thin-film transistor (TFT), a type of FET. The dual-gate oxide TFT was modified by adjusting both top and bottom gate insulators to improve capacitive coupling to approximately 120-fold amplification, exhibiting a high pH sensitivity of about 10 V/pH. The dual-gate oxide TFT-based immunosensor detected the target proteins (hemagglutinin (HA) protein of Flu, spike 1 (S1) protein of SARS-CoV-2, and fusion protein of RSV) of each virus, with a limit of detection of approximately 1 fg/mL. Cultured viruses in phosphate-buffered saline or artificial saliva and clinical nasopharynx samples were detected in 1-µL sample volumes within 60 s. This promising diagnosis could be potentially as point-of-care tests to facilitate a prompt response to future pandemics with high sensitivity and multiplexed detection without pretreatment.

Determination of online thin film buckling configuration by parametric optimization for flexible sensor application.

A mini basket type mapping catheter consists of thin film flexible sensors and is applied in the medical field to measure the electrocardiography (ECG) signals in order to localize and quantize the physiological condition/status of heart. The flexible nature of the thin film changes the configuration with respect to the contact boundary conditions when it contacts a target surface. Therefore, to accurately localize the flexible sensor, the thin film flexible sensor's configuration must be determined accurately in an on-line fashion. As a study of localizing the thin film flexible sensor, this study proposes an on-line thin film buckling configuration determination method using parametric optimization and interpolation technique. With the specific modulus of elasticity and dimensions of the thin film flexible sensor of the mapping catheter prototype, the buckling configuration with two point boundary condition under axial load can be calculated in desktop environment. The proposed calculation method is validated by mapping catheter sensor prototype test. The calculation/test results showed that the maximum overall length L, x[Formula: see text], and y[Formula: see text] value error between the calculation and experiment are approximately 0.16 mm, - 0.12 mm. - 0.10 mm in 50 ms calculation time. The calculation result of the proposed method is also compared with that of the numerical simulation by FEM, which has approximately 0.44 mm y[Formula: see text] value error compared with that of the experiment.

Ultrafast Nucleation Reverses Dissolution of Transition Metal Ions for Robust Aqueous Batteries.

The dissolution of transition metal ions causes the notorious peeling of active substances and attenuates electrochemical capacity. Frustrated by the ceaseless task of pushing a boulder up a mountain, Sisyphus of the Greek myth yearned for a treasure to be unearthed that could bolster his efforts. Inspirationally, by using ferricyanide ions (Fe(CN)63-) in an electrolyte as a driving force and taking advantage of the fast nucleation rate of copper hexacyanoferrate (CuHCF), we successfully reversed the dissolution of Fe and Cu ions that typically occurs during cycling. The capacity retention increased from 5.7% to 99.4% at 0.5 A g-1 after 10,000 cycles, and extreme stability of 99.8% at 1 A g-1 after 40,000 cycles was achieved. Fe(CN)63- enables atom-by-atom substitution during the electrochemical process, enhancing conductivity and reducing volume change. Moreover, we demonstrate that this approach is applicable to various aqueous batteries (i.e., NH4+, Li+, Na+, K+, Mg2+, Ca2+, and Al3+).

Radial-tangential mode of single-wall carbon nanotubes manifested by Landau regulation: reinterpretation of low- and intermediate-frequency Raman signals.

The low-frequency Raman signals of single-wall carbon nanotubes (SWNTs), appearing in the range of 100-300 cm-1, have been interpreted as radial-breathing mode (RBM) comprising pure radial Eigenvectors. Here, we report that most of the low-frequency and intermediate-frequency signals of SWNTs are radial-tangential modes (RTMs) coexisting radial and tangential Eigenvectors, while only the first peak at the low-frequency side is the RBM. Density functional theory simulation for SWNTs of ~ 2 nm in diameter shows that dozens of RTMs exhibit following the RBM (~ 150 cm-1) up to G-mode (~ 1592 cm-1) in order with Landau regulation. We specify the RBM and the RTM on Raman spectra obtained from SWNTs, where both appear as prominent peaks between 149 and 170 cm-1 and ripple-like peaks between 166 and 1440 cm-1, respectively. We report that the RTMs have been regarded as RBM (~ 300 cm-1) and ambiguously named as intermediate-frequency mode (300-1300 cm-1) without assignment. The RTMs gradually interlink the RBM and the G-mode resulting in the symmetric Raman spectra in intensity. We reveal high-resolution transmission microscope evidence for a helical structure of SWNTs, informing the typical diameter of commercial SWNTs to be 1.4-2 nm.

Composition-Tuned (MoWV)Se2 Ternary Alloy Nanosheets as Excellent Hydrogen Evolution Reaction Electrocatalysts.

Ternary alloying of transition metal dichalcogenides (TMDs) has the potential for altering the electronic structure of materials to suit electrochemical applications. Herein, we synthesized (MoWV)Se2 nanosheets at various compositions via a colloidal reaction. The mole fraction of V atoms (xV) was successfully increased up to 0.8, producing a metallic phase that is highly durable against hydration. Furthermore, we synthesized (MoW)Se2 nanosheets over the entire composition range. The atomic mixing of the ternary alloys is more random than that of the constitutional binary alloys, as supported by first-principles calculations. Compared to binary alloying, ternary alloying more effectively enhanced the electrocatalytic activity for acidic hydrogen evolution reaction (HER). The HER performance increased upon increasing xV to 0.44, and thereafter, it declined at higher xV primarily owing to surface oxidation. The analysis of Gibbs free energy for H adsorption revealed that ternary alloying strongly activates the basal plane for the HER. VSe2 contains numerous sites favorable for H adsorption, facilitating the composition-dependent HER. These results provide a pioneering strategy for designing multicomponent TMD catalysts that maximize the advantages of each component.

Full Composition Tuning of W1-xNbxSe2 Alloy Nanosheets to Promote the Electrocatalytic Hydrogen Evolution Reaction.

Composition modulation of transition metal dichalcogenides is an effective way to engineer their crystal/electronic structures for expanded applications. Here, fully composition-tuned W1-xNbxSe2 alloy nanosheets were produced via colloidal synthesis. These nanosheets ultimately exhibited a notable transition between WSe2 and NbSe2 hexagonal phases at x = 0.6. As x approaches 0.6, point doping is converted into cluster doping and eventually separated domains of WSe2 and NbSe2. Extensive density functional theory calculations predicted the composition-dependent crystal structures and phase transitions, consistently with the experiments. The electrocatalytic activity for the hydrogen evolution reaction (HER) in acidic electrolyte was significantly enhanced at x = 0.2, which was linked with the d-band center. The Gibbs free energy for the H adsorption at various basal and edge sites supported the enhanced HER performance of the metallic alloy nanosheets. We suggested that the dispersed doping structures of Nb atoms resulted in the best HER performance. Our findings highlight the significance of composition tuning in enhancing the catalytic activity of alloys.

MoSe2 -VSe2 -NbSe2 Ternary Alloy Nanosheets to Boost Electrocatalytic Hydrogen Evolution Reaction.

Alloying of transition metal dichalcogenides (TMDs) is a pioneering method for engineering electronic structures with expanded applications. In this study, MoSe2 -VSe2 -NbSe2 ternary alloy nanosheets are synthesized via a colloidal reaction. The composition is successfully tuned over a wide range to adjust the 2H-1T phase transition. The alloy nanosheets consist of miscible atomic structures at all compositions, which is distinct from immiscible binary alloys. Compared to each binary alloy, the ternary alloys display higher electrocatalytic activity toward the hydrogen evolution reaction (HER) in an acidic electrolyte. The HER performance exhibits a volcano-type composition dependence, which is correlated with the experimental d-band center (εd ). Spin-polarized density functional theory (DFT) calculations consistently predict the homogenous atomic distributions. The Gibbs free energy of H adsorption (ΔGH* ) and the activation barrier (Ea ) support that miscible ternary alloying greatly enhances the HER performance.

WSe2-VSe2 Alloyed Nanosheets to Enhance the Catalytic Performance of Hydrogen Evolution Reaction.

Tuning the electronic structures of transition metal dichalcogenides (TMD) is essential for their implementation in next-generation energy technologies. In this study, we synthesized composition-tuned WSe2-VSe2 (W1-xVxSe2, x = 0-1) alloyed nanosheets using a colloidal reaction. Alloying the semiconducting WSe2 with VSe2 converts the material into a metallic one, followed by a 2H-to-1T phase transition at x = 0.7. Over a wide composition range, WSe2 and VSe2 are atomically immiscible and form separate ordered domains. The miscible alloy at x = 0.1 displayed enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) in an acidic electrolyte. This trend was correlated with the d-band center via a volcano-type relationship. Spin-polarized density functional theory calculations consistently predicted the atomic immiscibility, which became more significant at the 2H-1T phase transition composition. The Gibbs free energy of H adsorption on the basal planes (Se or hole sites) and the activation barriers along the Volmer-Heyrovsky reaction pathway supported the enhanced HER performance of the alloy phase, suggesting that the dispersed V-doped structures were responsible for the best HER catalytic activity. Our study demonstrates how the atomic structure of TMD alloy nanosheets plays a crucial role in enhancing catalytic activity.

Interaction of Antifungal Drugs with CYP3A- and OATP1B-Mediated Venetoclax Elimination.

Venetoclax, a BCL-2 inhibitor used to treat certain hematological cancers, exhibits low oral bioavailability and high interpatient pharmacokinetic variability. Venetoclax is commonly administered with prophylactic antifungal drugs that may result in drug interactions, of which the underlying mechanisms remain poorly understood. We hypothesized that antifungal drugs may increase venetoclax exposure through inhibition of both CYP3A-mediated metabolism and OATP1B-mediated transport. Pharmacokinetic studies were performed in wild-type mice and mice genetically engineered to lack all CYP3A isoforms, or OATP1B2 that received venetoclax alone or in combination with ketoconazole or micafungin. In mice lacking all CYP3A isoforms, venetoclax AUC was increased by 1.8-fold, and pretreatment with the antifungal ketoconazole further increased venetoclax exposure by 1.6-fold, despite the absence of CYP3A. Ensuing experiments demonstrated that the deficiency of OATP1B-type transporters is also associated with increases in venetoclax exposure, and that many antifungal drugs, including micafungin, posaconazole, and isavuconazole, are inhibitors of this transport mechanism both in vitro and in vivo. These studies have identified OATP1B-mediated transport as a previously unrecognized contributor to the elimination of venetoclax that is sensitive to inhibition by various clinically-relevant antifungal drugs. Additional consideration is warranted when venetoclax is administered together with agents that inhibit both CYP3A-mediated metabolism and OATP1B-mediated transport.

Polytypic Phase Transition of Nb1-xVxSe2 via Colloidal Synthesis and Their Catalytic Activity toward Hydrogen Evolution Reaction.

Polytypes of two-dimensional transition metal dichalcogenide can extend the architecture and application of nanostructures. Herein, Nb1-xVxSe2 alloy nanosheets in the full composition range (x) were synthesized by a colloidal reaction. At x = 0.1-0.3, a phase transition occurred from various hexagonal (three 2H and one 4H types) phase NbSe2 to an atomically homogeneous 1T phase VSe2. Density functional theory calculations also revealed a polytypic phase transition at x = 0.3, which was shifted close to 0 in the presence of Se vacancies. Furthermore, the calculations validate favorable formation of Se vacancies at the phase transition. The sample at x = 0.3 exhibited enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) in 0.5 M H2SO4. The Gibbs free energy indicates that the catalytic HER performance is correlated with the active Se vacancy sites of polytypic structures.

An immunosensor based on a high performance dual-gate oxide semiconductor thin-film transistor for rapid detection of SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent of an infectious disease that has led the WHO to declare its highest level (6) pandemic. The coronavirus disease 2019 (COVID-19) has spread rapidly around the world, and the number of confirmed cases has passed 246 million as of November 2021. Therefore, precise and fast virus detection protocols need to be developed to cope with the rapid spread of the virus. Here, we present a high performance dual-gate oxide semiconductor thin-film transistor (TFT)-based immunosensor for detecting SARS-CoV-2. The immunosensor has an indium tin oxide sensing membrane to which the antibody against the SARS-CoV-2 spike S1 protein can be immobilized through functionalization. The dual-gate TFT was stable under ambient conditions with near-zero hysteresis; capacitive coupling yields a 10.14 ± 0.14-fold amplification of the surface charge potential on the sensing membrane and improves the pH sensitivity to 770.1 ± 37.74 mV pH-1 above the Nernst limit. The immunosensor could rapidly detect the SARS-CoV-2 spike S1 protein and cultured SARS-CoV-2 in 0.01× PBS with high antigen selectivity and sensitivity. Our immunosensor can accurately measure the electrical changes originated from SARS-CoV-2, without the need for polymerase chain reaction tests or labeling.

Prediction of Neoadjuvant Chemotherapy Response in Osteosarcoma Using Convolutional Neural Network of Tumor Center 18F-FDG PET Images.

We compared the accuracy of prediction of the response to neoadjuvant chemotherapy (NAC) in osteosarcoma patients between machine learning approaches of whole tumor utilizing fluorine-18fluorodeoxyglucose (18F-FDG) uptake heterogeneity features and a convolutional neural network of the intratumor image region. In 105 patients with osteosarcoma, 18F-FDG positron emission tomography/computed tomography (PET/CT) images were acquired before (baseline PET0) and after NAC (PET1). Patients were divided into responders and non-responders about neoadjuvant chemotherapy. Quantitative 18F-FDG heterogeneity features were calculated using LIFEX version 4.0. Receiver operating characteristic (ROC) curve analysis of 18F-FDG uptake heterogeneity features was used to predict the response to NAC. Machine learning algorithms and 2-dimensional convolutional neural network (2D CNN) deep learning networks were estimated for predicting NAC response with the baseline PET0 images of the 105 patients. ML was performed using the entire tumor image. The accuracy of the 2D CNN prediction model was evaluated using total tumor slices, the center 20 slices, the center 10 slices, and center slice. A total number of 80 patients was used for k-fold validation by five groups with 16 patients. The CNN network test accuracy estimation was performed using 25 patients. The areas under the ROC curves (AUCs) for baseline PET maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and gray level size zone matrix (GLSZM) were 0.532, 0.507, 0.510, and 0.626, respectively. The texture features test accuracy of machine learning by random forest and support vector machine were 0.55 and 0. 54, respectively. The k-fold validation accuracy and validation accuracy were 0.968 ± 0.01 and 0.610 ± 0.04, respectively. The test accuracy of total tumor slices, the center 20 slices, center 10 slices, and center slices were 0.625, 0.616, 0.628, and 0.760, respectively. The prediction model for NAC response with baseline PET0 texture features machine learning estimated a poor outcome, but the 2D CNN network using 18F-FDG baseline PET0 images could predict the treatment response before prior chemotherapy in osteosarcoma. Additionally, using the 2D CNN prediction model using a tumor center slice of 18F-FDG PET images before NAC can help decide whether to perform NAC to treat osteosarcoma patients.

AA h BN crystal, basic structure of boron nitride nanotubes.

AA h boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, Pm21), is reported here. This new AA h BN crystal exhibits a 'linear' morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) 'diagonal' electron-diffraction pattern, which have been experimentally demonstrated in this article. It is also demonstrated that this new crystal is the basic structure of multi-walled BN nanotubes (BNNTs) existing in the form of a helix. The helical AA h BNNTs exist in a metastable phase owing to 〈200〉 texture growth of the orthorhombic crystal, where the energy is ∼15 meV higher than that of stable AB or AA' BN. It is shown that the typical scanning electron microscope 'fluffy cotton-like' morphology of BNNTs is due to secondary growth of diverse BN sheets (including mono-layers) on incoherently scrolled wall strands of BNNTs, providing further evidence for the helical structure with HRTEM evidence for a left-handed helix.

Phase-Transition Mo1-xVxSe2 Alloy Nanosheets with Rich V-Se Vacancies and Their Enhanced Catalytic Performance of Hydrogen Evolution Reaction.

Alloys of transition-metal dichalcogenide can display distinctive phase evolution because of their two-dimensional structures. Herein, we report the colloidal synthesis of Mo1-xVxSe2 alloy nanosheets with full composition tuning. Alloying led to a phase transition at x = 0.7 from the semiconducting 2H phase MoSe2 to the metallic 1T phase VSe2. It also produced significant V and Se vacancies, which became the richest in the 2H phase at x = 0.3-0.5. Extensive spin-polarized density functional theory calculations consistently predicted the 2H-1T phase transition at x = 0.7, in agreement with the experimental results. The vacancy formation energy also supports the formation of V and Se vacancies. Alloying in the 2H phase enhanced the electrocatalytic performance toward hydrogen evolution reaction (HER) at x = 0.3 (in 0.5 M H2SO4) or 0.4 (in 1 M KOH). The Gibbs free energy along the HER pathway indicates that this maximum performance is due to the highest concentration of active V and Se vacancy sites.

Preliminary Radiogenomic Evidence for the Prediction of Metastasis and Chemotherapy Response in Pediatric Patients with Osteosarcoma Using 18F-FDF PET/CT, EZRIN and KI67.

Chemotherapy response and metastasis prediction play important roles in the treatment of pediatric osteosarcoma, which is prone to metastasis and has a high mortality rate. This study aimed to estimate the prediction model using gene expression and image texture features. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of 52 pediatric osteosarcoma patients were used to estimate the machine learning algorithm. An appropriate algorithm was selected by estimating the machine learning accuracy. 18F-FDG PET/CT images of 21 patients were selected for prediction model development based on simultaneous KI67 and EZRIN expression. The prediction model for chemotherapy response and metastasis was estimated using area under the curve (AUC) maximum image texture features (AUC_max) and gene expression. The machine learning algorithm with the highest test accuracy in chemotherapy response and metastasis was selected using the random forest algorithm. The chemotherapy response and metastasis test accuracy with image texture features was 0.83 and 0.76, respectively. The highest test accuracy and AUC of chemotherapy response with AUC_max, KI67, and EZRIN were estimated to be 0.85 and 0.89, respectively. The highest test accuracy and AUC of metastasis with AUC_max, KI67, and EZRIN were estimated to be 0.85 and 0.8, respectively. The metastasis prediction accuracy increased by 10% using radiogenomics data.

Hetero-Dimensional 2D Ti3C2Tx MXene and 1D Graphene Nanoribbon Hybrids for Machine Learning-Assisted Pressure Sensors.

Hybridization of low-dimensional components with diverse geometrical dimensions should offer an opportunity for the discovery of synergistic nanocomposite structures. In this regard, how to establish a reliable interfacial interaction is the key requirement for the successful integration of geometrically different components. Here, we present 1D/2D heterodimensional hybrids via dopant induced hybridization of 2D Ti3C2Tx MXene with 1D nitrogen-doped graphene nanoribbon. Edge abundant nanoribbon structures allow a high level nitrogen doping (∼6.8 at%), desirable for the strong coordination interaction with Ti3C2Tx MXene surface. For piezoresistive pressure sensor application, strong adhesion between the conductive layers and at the conductive layer/elastomer interface significantly diminishes the sensing hysteresis down to 1.33% and enhances the sensing stability up to 10 000 cycles at high pressure (100 kPa). Moreover, large-area pressure sensor array reveals a high potential for smart seat cushion-based posture monitoring application with high accuracy (>95%) by exploiting machine learning algorithm.

Iron-Palladium magnetic nanoparticles for decolorizing rhodamine B and scavenging reactive oxygen species.

HYPOTHESIS: Here, FePd magnetic nanoparticles (MNPs) are developed as artificial enzymes with high biocompatibility and reusability. EXPERIMENT: The nanoparticles (NPs) are synthesized in an aqueous solvent by one-pot synthesis utilizing glutathione (GSH) and cysteine (Cys) as surfactants. FINDINGS: The prepared hydrophilic FePd NPs are redispersible in water. Further, they exhibit catalytic activity for the degradation of rhodamine B (RhB), as well as for the inhibition of reactive oxygen species (ROS) production induced by H2O2, which are two- and seven-fold enhancements of their catalytic performances, respectively, compared with that of horseradish peroxidase. The computational simulation and electrochemical analysis indicate that the enhancement of the catalytic effect is due to the protection of the MNP surface by GSH and Cys. In vitro experiments reveal that FePd MNPs behave like a peroxidase and decrease the ROS in mammalian cells. The cytotoxicity assessment of FePd MNPs via exposures to different cell lines for over seven days indicates that they can maintain the cell viability of >90% for up to 20 µgmL-1 concentration. FePd MNPs with high saturation magnetization and biocompatibility can be utilized as recyclable peroxidase-mimicking nanozymes and biosensors in a variety of catalytic and biological applications.

Vascular Calcification in Patients Undergoing Total Knee Arthroplasty: Frequency and Effects on the Surgery.

BACKGROUD: This study aims to investigate the frequency of distal femoral and popliteal arterial calcification and to evaluate the intraoperative and postoperative effects of arterial calcification in patients undergoing total knee arthroplasty using a tourniquet. METHODS: The records of 5,438 patients who had undergone primary total knee arthroplasty between January 2003 and January 2017 were retrospectively reviewed. We examined the preoperative radiographs of the knee from all patients for calcifications of the femoral and popliteal arteries. Vascular calcification was identified on preoperative radiographs in 223 cases. Intraoperative and postoperative complications were investigated among these patients. Postoperative complications were analyzed from the time of surgery to the last follow-up (minimum 1-year follow-up). RESULTS: Vascular calcification of the arteries around the knee was found in 223 cases (4.1%). The mean patient age was 70.6 years in the non-calcification group and 73.8 years in the calcification group (p > 0.05). The calcification group was classified into medial, intimal, or mixed subgroups according to the morphology of calcification on preoperative radiographs. The medial type included 46 cases (20.6%); intimal type, 161 cases (72.2%); and mixed type, 16 cases (2.7%). There was no statistically significant difference in demographic and surgical data among the three groups. There were intraoperative complications in two cases in the medial type group, both of which involved tourniquet failure. There was also a postoperative complication in one case in the medial type group, which involved wound dehiscence at 2 weeks postoperatively. No other postoperative complications were identified during 1-year follow-up. CONCLUSIONS: Despite the presence of calcifications in the arteries around the knee, total knee arthroplasty (using a tourniquet) can be performed without serious complications.

Ruthenium Nanoparticles on Cobalt-Doped 1T' Phase MoS2 Nanosheets for Overall Water Splitting.

2D MoS2 nanostructures have recently attracted considerable attention because of their outstanding electrocatalytic properties. The synthesis of unique Co-Ru-MoS2 hybrid nanosheets with excellent catalytic activity toward overall water splitting in alkaline solution is reported. 1T' phase MoS2 nanosheets are doped homogeneously with Co atoms and decorated with Ru nanoparticles. The catalytic performance of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is characterized by low overpotentials of 52 and 308 mV at 10 mA cm-2 and Tafel slopes of 55 and 50 mV decade-1 in 1.0 m KOH, respectively. Analysis of X-ray photoelectron and absorption spectra of the catalysts show that the MoS2 well retained its metallic 1T' phase, which guarantees good electrical conductivity during the reaction. The Gibbs free energy calculation for the reaction pathway in alkaline electrolyte confirms that the Ru nanoparticles on the Co-doped MoS2 greatly enhance the HER activity. Water adsorption and dissociation take place favorably on the Ru, and the doped Co further catalyzes HER by making the reaction intermediates more favorable. The high OER performance is attributed to the catalytically active RuO2 nanoparticles that are produced via oxidation of Ru nanoparticles.