Search

The aquatic environment in aquaculture serves as the foundation for the survival and growth of aquatic animals, while a high-quality water environment is a necessary condition for promoting efficient and healthy aquaculture development. To effectively guide early warnings and the regulation of water quality in aquaculture, this study proposes a predictive model based on a dual-channel and dual-attention mechanism, namely, the DAM-ResNet-LSTM model. This model encompasses two parallel feature extraction channels: a residual network (ResNet) and long short-term memory (LSTM), with dual-attention mechanisms integrated into each channel to enhance the model's feature representation capabilities. Then, the proposed model is trained, validated, and tested using water quality and meteorological parameter data collected by an offshore farm environmental monitoring system. The results demonstrate that the proposed dual-channel structure and dual-attention mechanism can significantly improve the predictive performance of the model. The prediction accuracy for pH, dissolved oxygen (DO), and salinity (SAL) (with Nash coefficients of 0.9361, 0.9396, and 0.9342, respectively) is higher than that for chemical oxygen demand (COD), ammonia nitrogen (NH3-N), nitrite (NO2−), and active phosphate (AP) (with Nash coefficients of 0.8578, 0.8542, 0.8372, and 0.8294, respectively). Compared to the single-channel model DA-ResNet (ResNet integrated with the proposed dual-attention mechanism), the Nash coefficients for predicting pH, DO, SAL, COD, NH3-N, NO2−, and AP increase by 12.76%, 12.58%, 11.68%, 18.350%, 19.32%, 16%, and 14.99%, respectively. Compared to the single-channel DA-LSTM model (LSTM integrated with the proposed dual-attention mechanism), the corresponding increases in Nash coefficients are 9.15%, 9.93%, 9.11%, 10.91%, 10.11%, 10.39%, and 10.2%, respectively. Compared to the ResNet-LSTM (ResNet and LSTM in parallel) model without the attention mechanism, the improvements in Nash coefficients are 1.91%, 2.4%, 0.74%, 3.41%, 2.71%, 3.55%, and 4.13%, respectively. The predictive performance of the model fulfills the practical requirements for accurate forecasting of water quality in nearshore aquaculture. [ABSTRACT FROM AUTHOR]

In phase‐shifting interferometric measurement system, using wavelength‐tuned phase‐shifting technology to measure optical surface can improve vibration errors. However, the wavelength‐tuned phase‐shifting interferometry is greatly challenged by nonlinear distortion between wavelength‐tuned light intensity and voltage modulation, which has a certain impact on phase calculation accuracy. To address this issue, an adaptive light intensity‐aided interferometric measurement scheme is proposed in this study. To improve the adjustment time of voltage response, an improved fuzzy single‐neuron adaptive proportional differential integral constant amplitude control algorithm is built. By exploiting the online detection and feedback control of light intensity, the stable output of light intensity is integrated into phase‐shifting measurement system. Experiment results verify that the improvement of light intensity fluctuation range, root mean square, and peak‐to‐valley measurement repeatability can be achieved with the proposed scheme. [ABSTRACT FROM AUTHOR]

Sensitive and stable triethylamine (TEA) gas sensors are desirable for environmental and human safety. However, the high operating temperature of the metal-oxide-based gas sensors poses a limitation on their wide applications. Herein, we fabricate an exceptional TEA gas sensor based on the core–shell heterostructure comprising crystalline CuO and amorphous In2O3/ZnO (CuInZnO) via a facile electrodeposition method. Remarkably, the optimum gas sensor (CuInZnO-3) exhibits an outstanding gas response (∼25) toward a 10 ppm TEA at room temperature. Moreover, CuInZnO-3 shows excellent selectivity, linear response, and stability. The superior sensing performance can be mainly ascribed to the unique core–shell nanorod heterostructure with a high specific surface area, allowing the formation of p–n junctions. The amorphous nature of the In2O3/ZnO shell also enriches the active oxygen on the surface and enhances gas adsorption. [ABSTRACT FROM AUTHOR]

We propose a strategy to etch dopants to construct Mo2C with more unsaturated coordination of Mo atoms and lattice distortion for enhanced catalytic activity. It is more effective than doping and etching pure Mo2C and provides a novel strategy for the preparation of catalysts with high catalytic activity. [ABSTRACT FROM AUTHOR]

The electrochemical corrosion behavior of X70 pipeline steel in a simulated solution of Qinzhou's strongly acidic latosol within a range of temperature from 30 °C to 70 °C was studied by electrochemical impedance spectroscopy, polarization curve measurement, immersion weight loss method, and X-ray diffraction. The effect of temperature on corrosion resistance of X70 pipeline steel was discussed. The results showed that as the temperature rose, the polarization resistance of X70 pipeline steel in the simulated solution decreased, the corrosion potential shifted negatively, and the corrosion current density increased, indicating that the corrosion rate of X70 pipeline steel increased and its corrosion resistance became worse. The dissolution of Fe occurred at the anode, while hydrogen evolution and oxygen depolarization occurred at the cathode. The phase constitution of the corrosion product on the surface of X70 pipeline steel was affected by variation of temperature. The corrosion products were the same at 30 °C and 40 °C, but different at 50, 60, and 70 °C, comprising γ-FeO(OH), Fe(OH)3, Fe3O4, α-FeO(OH), and Fe2O3. The film of corrosion product became looser with the increasing of temperature, and the corrosion of X70 pipeline steel became more and more serious. [ABSTRACT FROM AUTHOR]

Applying metal–organic framework (MOF) materials to perovskite solar cells (PSCs) is an innovative and promising direction in the current photovoltaic field, especially in low‐cost carbon‐based PSCs without hole transport layer. Herein, a novel mesoporous anatase TiO2 nanocrystalline with pie morphology, large specific surface area (SSA), and outstanding wettability is successfully prepared by sintering the NH2‐MIL‐125 at 500 °C for 6 h. The TiO2 derived from NH2‐MIL‐125 possesses excellent penetration and crystallinity of perovskite in the electron transporting layer (ETL), and exhibits appropriate work function which matches relatively better with the conduction band of perovskite. Meanwhile, the power conversion efficiencies (PCEs) of the two PSC devices based on the as‐prepared TiO2 are 13.49% and 12.55%, respectively. Moreover, both of these devices exhibit good stability. [ABSTRACT FROM AUTHOR]

The phase of an interferogram carries the desired information for various applications such as 3-D profilometry. It can be obtained with a wavelength tuning interferometer by acquiring a series of interferograms while changing the laser wavelength. The phase achieved by the interferometer, however, has severe error due to the laser output power change, which is produced inherently from changing the laser wavelength. To eliminate such phase error, we propose a real-time closed-loop feedback control system to keep the laser output power stable during the wavelength tuning. The control system integrates a photodetector, a data acquisition card, and an electro-optic amplitude modulator with our software to achieve the purpose. The experimental result of the system can steadily output a desired intensity value and the measurement speed is up to 600 KHz. Both its control principles as well as its experimental validation are depicted in this letter. [ABSTRACT FROM AUTHOR]

Developing highly active and stable electrocatalysts for hydrogen production at industrial current densities is pivotal to give an impetus to carbon neutrality. Recently, metal–organic frameworks (MOFs) with large surface area and adjustable structures have become a class of promising alternative electrocatalysts, while their low conductivity and poor stability limit their widespread applications. Here, a modified strategy is proposed to stabilize and modulate Ruthenium (Ru) species including Ru single atoms (Ru SAs) and Ru nanoparticles (Ru NPs) on MOFs for enhanced hydrogen evolution reaction (HER). Benefiting from the strong interaction between Ru and MOFs, the synthesized NiFeRuSA+NP‐DOBDC (DOBDC: 2,5‐dioxido‐1,4‐benzenedicarboxylate) exhibits an extraordinary HER performance with overpotentials of 25 and 271 mV at 10 and 1000 mA cm−2, respectively. Meanwhile, it enables robust HER at a high current density of 1 A cm−2 over 300 h. Remarkably, the assembled anion exchange membrane (AEM) electrolyzer realizes a low voltage for alkaline water electrolysis. In situ analyses demonstrate that NiFeRuSA+NP‐DOBDC enables optimized H2O adsorption and dissociation, and theoretical calculations indicate that Ru SAs and NPs accelerate the Volmer‐Heyrovsky pathway, synergistically promoted the HER performance. This work presents a competitive strategy to integrate supported metal species on the MOFs platform to efficiently drive industrial water electrolysis. [ABSTRACT FROM AUTHOR]

Carbon materials have been widely used as electrode materials for supercapacitors, while the current carbon precursors are mainly derived from fossil fuels. Biomass-derived carbon materials have become new and effective materials for electrodes of supercapacitors due to their sustainability, low pollution potential, and abundant reserves. Herein, we present a new biomass carbon material derived from water hyacinth by a novel activation method (combination of KOH and HNO3 activation). According to the electrochemical measurements, the material presents an ultrahigh capacitance of 374 F g−1 (the current density is 1 A g−1). Furthermore, the material demonstrates excellent rate performance (105 F g−1 at a higher density of 20 A g−1) and ideal cycling stability (87.3% capacity retention after 5000 times charge–discharge at 2 A g−1). When used for a symmetrical supercapacitor device, the material also shows a relatively high capacity of 330 F g−1 at 1 A g−1 (a two-electrode system). All measurements suggest the material is an effective and noteworthy material for the electrodes of supercapacitors. [ABSTRACT FROM AUTHOR]

Hydrogen production by photocatalysis water splitting is an attractive and promising development method, but the current efficiency is too low for application. Loading single atoms can significantly enhance the photocatalytic efficiency, however, the insightful understanding of the impact of single atom loading on catalytic performance is still ambiguous. In this work, In SA /TiO 2 photocatalysts modified with indium single atom (In SA) were synthesized by photo-deposition process. Under 300W Xe lamp illumination, the hydrogen production rate of the optimized In SA /TiO 2 photocatalyst achieves 6.11 mmol g−1 h−1, which is 7.6 times that of TiO 2 prepared under the same conditions. The results of characterization analysis and density functional theory (DFT) calculations indicate that some of the Ti atoms on the TiO 2 surface are replaced by the doped In, and the local electronic structures of the photocatalyst are regulated, which results in effectively separating of the photo-generated carriers, and significant increasing the activity of the surrounding unsaturated oxygen, thus, the photocatalytic hydrogen production performance is effectively improved. This work provides a strategy to improve photocatalytic activity, and also deepens the understanding of metal single atom modification mechanism. • In SA significant increasing the activity of the surrounding O Vs. • The surface local electronic structures of TiO 2 are regulated by loading In SA. • H 2 evolution rate of In SA /TiO 2 is 7.6 times that of TiO 2 under 300W Xe illumination. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

Replacing the oxygen evolution reaction (OER) with the urea oxidation reaction (UOR) in conjunction with the hydrogen evolution reaction (HER) offers a feasible and environmentally friendly approach for handling urea-rich wastewater and generating energy-saving hydrogen. However, the deactivation and detachment of active sites in powder electrocatalysts reported hitherto present significant challenges to achieving high efficiency and sustainability in energy-saving hydrogen production. Herein, a self-supported bimetallic nickel manganese metal-organic framework (NiMn-MOF) nanosheet and its derived heterostructure composed of NiMn-MOF decorated with ultrafine Pt nanocrystals (Pt NC /NiMn-MOF) are rationally designed. By leveraging the synergistic effect of Mn and Ni, along with the strong electronic interaction between NiMn-MOF and Pt NC at the interface, the optimized catalysts (NiMn-MOF and Pt NC /NiMn-MOF) exhibit substantially reduced potentials of 1.459 and -0.129 V to reach 1000 mA cm -2 during the UOR and HER. Theoretical calculations confirm that Mn-doping and the heterointerface between NiMn-MOF and Pt nanocrystals regulate the d-band center of the catalyst, which in turn enhances electron transfer and facilitates charge redistribution. This manipulation optimizes the adsorption/desorption energies of the reactants and intermediates in both the HER and UOR, thereby significantly reducing the energy barrier of the rate-determining step (RDS) and enhancing the electrocatalytic performance. Furthermore, the urea degradation rates of Pt NC /NiMn-MOF (96.1%) and NiMn-MOF (90.3%) are significantly higher than those of Ni-MOF and the most reported advanced catalysts. This work provides valuable insights for designing catalysts applicable to urea-rich wastewater treatment and energy-saving hydrogen production.

The development of high-activity photocatalysts is crucial for the current large-scale development of photocatalytic hydrogen applications. Herein, we have developed a strategy to significantly enhance the hydrogen photocatalytic activity of Cu/Pr di-atom co-modified TiO 2 architectures by selectively anchoring Cu single atoms on the oxygen vacancies of the TiO 2 surface and replacing a trace of Ti atoms in the bulk with rare earth Pr atoms. Calculation results demonstrated that the synergistic effect between Cu single atoms and Pr atoms regulates the electronic structure of Cu/Pr-TiO 2 , thus promoting the separation of photogenerated carriers and their directional migration to Cu single atoms for the photocatalytic reaction. Furthermore, the d-band center of Cu/Pr-TiO 2 , which is located at -4.70 eV, optimizes the adsorption and desorption behavior of H*. Compared to TiO 2 , Pr-TiO 2 , and Cu/TiO 2 , Cu/Pr-TiO 2 displays the best H* adsorption Gibbs free energy (-0.047 eV). Furthermore, experimental results confirmed that the photogenerated carrier lifetime of Cu/Pr-TiO 2 is not only the longest (2.45 ns), but its hydrogen production rate (34.90 mmol g -1 h -1 ) also significantly surpasses those of Cu/TiO 2 (13.39 mmol g -1 h -1 ) and Pr-TiO 2 (0.89 mmol g -1 h -1 ). These findings open up a novel atomic perspective for the development of optimal hydrogen activity in dual-atom-modified TiO 2 photocatalysts.

Photocatalytic water splitting for clean hydrogen production has been a very attractive research field for decades. However, the insightful understanding of the actual active sites and their impact on catalytic performance is still ambiguous. Herein, a Pr-doped TiO 2 -supported Cu single atom (SA) photocatalyst is successfully synthesized (noted as Cu/Pr-TiO 2 ). It is found that Pr dopants passivate the formation of oxygen vacancies, promoting the density of photogenerated electrons on the CuSAs, and optimizing the electronic structure and H * adsorption behavior on the CuSA active sites. The photocatalytic hydrogen evolution rate of the obtained Cu/Pr-TiO 2 catalyst reaches 32.88 mmol g -1  h -1 , 2.3 times higher than the Cu/TiO 2 . Innovatively, the excellent catalytic activity and performance is attributed to the active sites change from O atoms to CuSAs after Pr doping is found. This work provides new insight for understanding the accurate roles of single atoms in photocatalytic water splitting., (© 2024 Wiley‐VCH GmbH.)

Exploring highly efficient hydrogen evolution reaction (HER) electrocatalysts for large-scale water electrolysis in the full potential of hydrogen (pH) range is highly desirable, but it remains a significant challenge. Herein, a simple pathway is proposed to synthesize a hybrid electrocatalyst by decorating small metallic platinum (Pt) nanosheets on a large nickel telluride nanosheet (termed as Pt Ns /NiTe-Ns). The as-prepared Pt Ns /NiTe-Ns catalyst only requires overpotentials of 72, 162, and 65 mV to reach a high current density of 200 mA cm -2 in alkaline, neutral and acidic conditions, respectively. Theoretical calculations reveal that the combination of metallic Pt and NiTe-Ns subtly modulates the electronic redistribution at their interface, improves the charge-transfer kinetics, and enhances the performance of Ni active sites. The synergy between the Pt site and activated Ni site near the interface in Pt Ns /NiTe-Ns promotes the sluggish water-dissociation kinetics and optimizes the subsequent oxyhydrogen/hydrogen intermediates (OH*/H*) adsorption, accelerating the HER process. Additionally, the superhydrophilicity and superaerophobicity of Pt Ns /NiTe-Ns facilitate the mass transfer process and ensure the rapid desorption of generated bubbles, significantly enhancing overall alkaline water/saline water/seawater electrolysis catalytic activity and stability., (© 2023 Wiley-VCH GmbH.)

One of the most promising strategies for producing hydrogen is photocatalytic water splitting, in which the photocatalyst is a key component. Among many semiconductor photocatalysts, g-C 3 N 4 has attracted great attention due to its narrow band gap, excellent stability and low cost. However, practical application is limited by its poor intrinsic activity. In this work, a high-performance porous g-C 3 N 4 (PCN) photocatalyst with anchored Cu single atoms (CuSAs) was synthesized by a one-step co-heating approach. The obtained Cu1.5-PCN displays an excellent hydrogen evolution rate (HER) of 2142.4 μmol h -1 g -1 under visible light (=420 nm), which is around 15 and 109 times higher than those of PCN and bulk g-C 3 N 4 , respectively. In addition, it also shows good stability during H 2 evolution. The results of experimental research and DFT simulations indicate that the single Cu ions formed bonds with the N-ring and these remain stable. Meanwhile, the special electronic structure of the Cu-N charge bridge extends the light absorption band to the visible-light region (380-700 nm). This high-performance and low-cost photocatalyst has great potential in solar energy conversion., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Owing to the advantages of high theoretical capacity, low cost, and excellent chemical stability, Ni(OH) 2 is considered as a potential candidate for electrode materials of supercapacitors. However, its further applications are limited by its adverse surface chemical properties. In this paper, a composite material consisting of ZIF-67 derived Co-C-N nanosheets and Ni(OH) 2 was synthesized facilely on carbon cloth in situ , and based on the collective advantages of the various components, excellent electrochemical performance could be achieved when used as a flexible electrode material of supercapacitors. In detail, the as-obtained sample Ni(OH) 2 /Co-C-N/CC exhibits an ultrahigh specific capacitance of 2100 F g -1 at a current density of 1 A g -1 . Moreover, the further assembled asymmetric supercapacitor device exhibits a maximum energy density of 78.6 W h kg -1 at a power density of 749.4 W kg -1 . Furthermore, the device also shows outstanding cycling stability with 90.2% capacitance retention after 5000 cycles of charge-discharge. Basically, the remarkable performance can be attributed to the well-developed structure, abundant active sites, complex beneficial components, and their intrinsic properties. Significantly, rational design can broaden the research directions of corresponding electrode materials., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The separation of misalignment aberrations is a crucial step in interferometric testing for the acquisition of the real surface. In this paper, a Fizeau interference system and a conical mirror with a certain angle were used to achieve the shape measurement of the inner surface of the frustum of a cone. Based on the ray-tracing method, the relationship between the adjustment errors and misalignment aberrations was established, and the misalignment aberrations could be removed by using the error separation model that accords with the least-square algorithm theory. The simulation and practical measurement results indicate that the approach proposed is valid and feasible.