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•Vo-BiVO4/FeOOH photoanode was prepared by hydrothermal and photodeposition treatment.•Oxygen vacancy and FeOOH cocatlayst enhance the charge transfer and separation ...efficiency.•Vo-BiVO4/FeOOH photoanode demonstrated excellent PEC performance than prsitine BiVO4.
Herein, a new approach of inducing oxygen vacancy in BiVO4/FeOOH nanostructures is designed, where metal trichalcogenide is introduced. The strategy involves integration of Bi2S3 quantum dots (QDs) in BiVO4/FeOOH to construct defect-rich BiVO4/FeOOH (denoted Vo-BiVO4/FeOOH) as high-performance photoanode for photoelectrochemical water oxidation. Both experimental and theoretical analysis confirm that the excellent PEC performance is due to the introduction of oxygen vacancies and FeOOH cocatalyst, which significantly improves the charge separation. As a result, the obtained Vo-BiVO4/FeOOH photoanode not only demonstrates an optimized Photoelectrochemical (PEC) performance for water oxidation, with photocurrent density of 4.71 mA cm−2 at 1.23 V versus RHE under AM 1.5 G illumination but the interaction of BiVO4 with FeOOH cocatlayst also significantly enhance the stability for Vo-BiVO4/FeOOH without any decrease after 11 h. The oxygen vacancy and FeOOH can effectively enhance the light conversion efficiency, charge transfer efficiencies and charge separation efficiency. This work highlights an effective strategy towards achieving efficient and stable BiVO4 photoanode for sustainable solar energy conversion.
Atomically thin materials (ATMs) with thicknesses in the atomic scale (typically <5 nm) offer inherent advantages of large specific surface areas, proper crystal lattice distortion, abundant surface ...dangling bonds, and strong in-plane chemical bonds, making them ideal 2D platforms to construct high-performance electrode materials for rechargeable metal-ion batteries, metal-sulfur batteries, and metal-air batteries. This work reviews the synthesis and electronic property tuning of state-of-the-art ATMs, including graphene and graphene derivatives (GE/GO/rGO), graphitic carbon nitride (g-C3N4), phosphorene, covalent organic frameworks (COFs), layered transition metal dichalcogenides (TMDs), transition metal carbides, carbonitrides, and nitrides (MXenes), transition metal oxides (TMOs), and metal-organic frameworks (MOFs) for constructing next-generation high-energy-density and high-power-density rechargeable batteries to meet the needs of the rapid developments in portable electronics, electric vehicles, and smart electricity grids. We also present our viewpoints on future challenges and opportunities of constructing efficient ATMs for next-generation rechargeable batteries.
We herein demonstrate the unusual effectiveness of two strategies in combination to enhance photoelectrochemical water splitting. First, the work function adjustment via molybdenum (Mo) doping ...significantly reduces the interfacial energy loss and increases the open-circuit photovoltage of bismuth vanadate (BiVO
) photoelectrochemical cells. Second, the creation and optimization of the heterojunction of boron (B) doping carbon nitride (C
N
) and Mo doping BiVO
to enforce directional charge transfer, accomplished by work function adjustment via B doping for C
N
, substantially boost the charge separation of photo-generated electron-hole pairs at the B-C
N
and Mo-BiVO
interface. The synergy between the above efforts have significantly reduced the onset potential, and enhanced charge separation and optical properties of the BiVO
-based photoanode, culminating in achieving a record applied bias photon-to-current efficiency of 2.67% at 0.54 V vs. the reversible hydrogen electrode. This work sheds light on designing and fabricating the semiconductor structures for the next-generation photoelectrodes.
When identifying the key features of the network intrusion signal based on the GA-RBF algorithm (using the genetic algorithm to optimize the radial basis) to identify the key features of the network ...intrusion signal, the pre-processing process of the network intrusion signal data is neglected, resulting in an increase in network signal data noise, reducing the accuracy of key feature recognition. Therefore, a key feature recognition algorithm for network intrusion signals based on neural network and support vector machine is proposed. The principal component neural network (PCNN) is used to extract the characteristics of the network intrusion signal and the support vector machine multi-classifier is constructed. The feature extraction result is input into the support vector machine classifier. Combined with PCNN and SVM (Support Vector Machine) algorithms, the key features of network intrusion signals are identified. The experimental results show that the algorithm has the advantages of high precision, low false positive rate and the recognition time of key features of R2L (it is a common way of network intrusion attack) data set is only 3.18 ms.
Achieving high-efficiency photoelectrochemical water splitting requires a better understanding of ion kinetics, e.g., diffusion, adsorption and reactions, near the photoelectrode's surface. However, ...with macroscopic three-dimensional electrodes, it is often difficult to disentangle the contributions of surface effects to the total photocurrent from that of various factors in the bulk. Here, we report a photoanode made from a InSe crystal monolayer that is encapsulated with monolayer graphene to ensure high stability. We choose InSe among other photoresponsive two-dimensional (2D) materials because of its unique properties of high mobility and strongly suppressing electron-hole pair recombination. Using the atomically thin electrodes, we obtained a photocurrent with a density >10 mA cm
at 1.23 V versus reversible hydrogen electrode, which is several orders of magnitude greater than other 2D photoelectrodes. In addition to the outstanding characteristics of InSe, we attribute the enhanced photocurrent to the strong coupling between the hydroxide ions and photo-generated holes near the anode surface. As a result, a persistent current even after illumination ceased was also observed due to the presence of ions trapped holes with suppressed electron-hole recombination. Our results provide atomically thin materials as a platform for investigating ion kinetics at the electrode surface and shed light on developing next-generation photoelectrodes with high efficiency.
Boosting oxygen evolution reaction by local surface plasmon resonance (LSPR) provides breakthrough opportunities for the promotion of solar energy conversion; the potential of LSPR, however, has ...rarely been tapped and investigated. Here, we report the precise regulation of commercial Au nanoparticles plasmonic nanomaterial and OER electrocatalysts, viz., the NiCoOx electrocatalytic layer with hole transport ability and photothermal effect is prepared on the surface of Au nanoparticles by photoelectrodeposition. The NiCoOx layer not only increases the transmission distance of holes generated by plasmonic Au nanoparticles, but also reduce the agglomeration of plasmonic Au nanoparticles during long‐time OER reaction, which greatly improves the OER catalytic ability. The current density of NiCoOx/Au anode achieves 16.58 mA cm−2 at 2.0 V versus RHE, which is about 6.5 times of pristine NiCoOx anode (2.56 mA cm−2) and 47 times of pristine Au anode (0.35 mA cm−2). More importantly, with the LSPR and photothermal effect of plasmonic Au nanoparticles, the NiCoOx/Au anode provides additional current density of 7.01 mA cm−2 after illumination, and maintains no attenuation for more than 2000 s. Benefiting from the solution of agglomeration problem of plasmonic Au nanoparticles in the long‐time OER process and the effective utilization of generated holes of plasmonic Au nanoparticles, this design can provide guidance for the application of plasmonic materials in the field of electrocatalysis.
Au nanoparticles generate photogenerated charge and hot charge of the LSPR effect after illumination, in which electrons are transported to Pt counter electrode for HER with water. Due to the property of NiCoOx that only transmits holes but prevents the transfer of electrons, the holes are transmitted to NiCoOx to react with OH− to form O2. Therefore, the separation of hot holes produced by the LSPR effect and its catalytic ability of OER are promoted.
Polyaniline (PANI), with its low cost, chemical stability and high conductivity, is used as a hole transporting layer to fabricate NiOOH/PANI/BiVO4 (NPB) photoanode, of which the photoelectrochemical ...(PEC) water splitting performance is significantly enhanced. The remarkable water oxidation photocurrent of NPB photoanode achieves 3.31 mA cm−2 at 1.23 V vs. RHE under AM 1.5G solar light irradiation, which is greatly increased compared with that of pristine BiVO4 (0.89 mA cm−2 under the same condition). The maximal incident photon-to-current conversion efficiency achieves 83.3% at 430 nm at 1.23 V vs. RHE and the maximal applied bias photo-to-current efficiency reaches 1.20% at 0.68 V vs. RHE, which are nearly five and ten times higher than that of pristine BiVO4 photoanode, respectively. This NPB photoanode exhibits excellent stability with about 97.22% Faraday efficiency after PEC water splitting for 3 h. The exciting results demonstrate that PANI shows great potential as a hole-transporting layer for photoanode and NPB is an efficient and stable photoanode material with a great potential application in PEC water splitting. Overall, this work provides an excellent reference on designing and fabricating photoanode materials for the future.
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•PANI as a hole-transporting layer was used to fabricate NiOOH/PANI/BiVO4 photoanode.•NPB showed higher PEC water splitting performance than most BiVO4-based photoanode.•NiOOH/PANI/BiVO4 exhibited excellent stability with high Faraday efficiency.•PANI transported holes to NiOOH for water oxidation reaction and isolated electrons.•PANI had great potential as a hole-transporting layer for water splitting photoanode.
Cassidy et al. of Trinity College in Dublin, Ireland, studied the social structure of farming communities, focusing on the ancient nobles buried in passage tombs (a channel-style megalithic tomb ...structure in Europe). Newgrange, built by complex engineering technology, is the most famous stone tunnel tomb in Ireland and one of the most famous prehistoric cemeteries in the country. The tomb is at the end of a stone-lined passage, with an opening like a window above the mausoleum entrance. On the shortest day of the year (winter solstice), this opening allows sunlight to enter the tomb. Researchers conducted DNA analysis of ancient human remains found in the tomb, revealing a rare and unexpected incident of incest. A man buried in Newgrange's tomb about 5000 years ago was the offspring of an incestuous marriage: his parents were either siblings or parents and children. This discovery led the researchers to speculate that the nobles associated with this magnificent tomb may have maintained their bloodlines through incest.①①Original source in Chinese: Kai Ye, The intersection of archaeology and genomics: Sparking the advances in cognitive human society, Bulletin of National Natural Science Foundation of China. 35 (2) (2021) 238-239.
One of the breakthroughs in biomaterials and regenerative medicine in the latest decade is the finding that matrix stiffness affords a crucial physical cue of stem cell differentiation. This ...statement was recently challenged by another understanding that protein tethering on material surfaces instead of matrix stiffness was the essential cue to regulate stem cells. Herein, we employed nonfouling poly(ethylene glycol) (PEG) hydrogels as the matrix to prevent nonspecific protein adsorption, and meanwhile covalently bound cell-adhesive arginine-glycine-aspartate (RGD) peptides onto the hydrogel surfaces in the form of well-defined nanoarrays to control specific cell adhesion. This approach enables the decoupling of the effects of matrix stiffness and surface chemistry. Mesenchymal stem cells (MSCs) were cultured on four substrates (two compressive moduli of the PEG hydrogels multiplied by two RGD nanospacings) and incubated in the mixed osteogenic and adipogenic medium. The results illustrate unambiguously that matrix stiffness is a potent regulator of stem cell differentiation. Moreover, we reveal that RGD nanospacing affects spreading area and differentiation of rat MSCs, regardless of the hydrogel stiffness. Therefore, both matrix stiffness and nanoscale spatial organization of cell-adhesive ligands direct stem cell fate.
Herein, we report an effective synthesis method of BiOI/BiVO4 p–n junction that greatly improves the performance of BiVO4 for photoelectrochemical water splitting due to a synergistic effect. The ...photocurrent density of BiOI/BiVO4 photoanodes achieved 3.27mAcm2 at 1.23V vs. RHE, which is much higher than those of pristine BiVO4 and BiOI (1.23mAcm2 and 0.15mAcm2 at 1.23V vs. RHE, respectively). At 0.68eV vs. RHE, BiOI/BiVO4 shows the maximum of applied bias photo-to-current efficiency of 0.97% at 0.68V vs. RHE. This new BiOI/BiVO4 p–n junction not only facilitates the separation and transfer of photo-generated charges, but also expands the light absorption range, which is the origin for this synergistic effect. The BiOI/BiVO4 p–n junction materials with excellent solar water splitting capability should shed light on designing and fabricating the next-generation photocatalysts.
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•BiOI/BiVO4 shows greatly improved photoelectrochemical water splitting capability.•Its photocurrent density achieves 3.27mAcm2 at 1.23V vs. RHE.•Its Faraday efficiency retains 95% after 10h illumination.•The p–n junction is believed to play a critical role in this significant enhancement.
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