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It is significant to develop low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) via electrochemical water splitting. Herein, we constructed P-doped NiCo2S4 nanowire arrays on carbon fiber paper (NiCo2S4−xPx/CFP) as a HER electrocatalyst in both acidic and alkaline media. Benefitting from P doping into NiCo2S4, the as-prepared NiCo2S4−xPx/CFP exhibits low HER overpotentials of 80 and 132 mV in acidic and alkaline media at a cathodic current density of 10 mA cm−2, respectively, which are far superior to counterparts of NiCo2S4 nanowire arrays on the carbon fiber paper (NiCo2S4/CFP). Meanwhile, the NiCo2S4−xPx/CFP presents excellent HER stability of 20 hours in acidic and alkaline media. From the results of density functional theory calculations, P doping can not only optimize the hydrogen adsorption energetics on each kind of atomic site of catalysts, but also strengthen the H2O molecule binding ability on the catalyst surface for the alkaline HER and favor kinetics of hydrogen adsorption and H2 formation on the catalyst surface for the acidic HER, eventually improving overall HER performances. The investigation of the HER mechanism modulated by P doping in our work offers novel inspiration to develop highly efficient ternary metal sulfides for the HER. [ABSTRACT FROM AUTHOR]

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions—argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts—resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors. [ABSTRACT FROM AUTHOR]

Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]

The effective integration of nanomaterials with underlying current collectors is a key factor affecting the performance of nonenzymatic glucose sensors, where an inappropriate integration structure often leads to poor electron transport and instability. In this work, a seamless integrated electrode was constructed by the in situ immobilizing of a nickel-based metal-organic framework (Ni-MOF) on a three-dimensional (3D) conductive nickel foam (NF) for highly sensitive and durable glucose sensing. Facilitated by a rapid microwave-assisted reaction, a robust interfacial interaction between the Ni-MOF and the substrate was established through in situ conversion from nickel oxide (NiO). The fabricated Ni-MOF/NF electrode exhibits an excellent limit of detection (LOD) of 2.65 μM and an impressive sensitivity (14.31 mA cm-2 mM-1) within the linear range (4-576 μM), which is significantly boosted compared with that of an electrode prepared by a typical drop-casting method (3.56 mA cm-2 mM-1 in 4-1836 μM). Characterization and electrochemical tests reveal that this integrated structure on the one hand contributes to fast electron transport and thus has enhanced sensitivity and on the other hand leads to exceptional durability with its structural integrity maintained under bending, shaking, and ultrasonication. Moreover, this seamless integration method was also employed to immobilize the Ni-MOF converted from the pre-chemically deposited NiO layer on another type of substrate, 3D carbon paper (CP), demonstrating the versatility of this facile strategy in creating diverse electrochemical electrodes for applications beyond glucose sensing. [ABSTRACT FROM AUTHOR]

This report presents an investigation into the use of carbon paper electrodes prepared from chitosan-adhered graphene magnetite nanoparticles for the analysis of Cr(VI). The preparation and storage of carbon paper electrodes is a simple process, and these electrodes are easier to replace than electrodes modified by more conventional methods. The electrochemical detection of Cr(VI) using square wave adsorption cathodic dissolution voltammetry (SWAdCSV) with high selectivity and sensitivity, as well as the optimum conditions for the preparation of the electrodes and the electrode parameters affecting the SWAdCSV signal, were the main points of focus of the investigation. Cr(VI) was detected linearly in the range of 4-40 μg L-1 with a detection limit of 2.84 μg L-1. The electrode output precision, calculated as %RSD, was 7.16% (n = 6), and this was the measurement used for the detection of Cr(VI) in standard and test samples with recoveries between 89% and 114%. The results were consistent with those obtained using the standard UV-Vis spectrophotometric method with a paired t-test at 95% confidence level. [ABSTRACT FROM AUTHOR]

Developing cost-effective and stable materials for the electrocatalysis of hydrogen evolution reaction (HER) remains challenging. In this study, efficient catalysts for HER were synthesized by integrating the cobalt and molybdenum oxides via electrodeposition, followed by subsequent sulfurization of the as-prepared oxides using chemical vapor deposition (CVD). This methodology allowed the incorporation of both cobalt and molybdenum components into the catalyst in a single step. The as-synthesized CoSx@MoSx/MoOx-based catalysts exhibited excellent hydrogen production performance in acidic media owing to the presence of Co-S and Mo-S bonds in the hybrid structure. Particularly, CoSx@MoSx/MoOx(90@360) and MoSx@CoOx(180@180) displayed the best HER performances with low overpotentials of 80 mV and 150 mV, respectively. The catalysts were highly stable, with their stability preserved for over 1000 cycles with marginal reduction in overall efficiency. Therefore, these findings suggest the potential of CoSx@MoSx/MoOx and MoSx@CoOx composites as ideal candidates for developing low-cost catalysts for electrochemical hydrogen production. [ABSTRACT FROM AUTHOR]

The present study examines the assumptions, modeling structure, and results of DICE-2023, the revised Dynamic Integrated Model of Climate and the Economy (DICE), updated to 2023. The revision contains major changes in the treatment of risk, the carbon and climate modules, the treatment of nonindustrial greenhouse gases, discount rates, as well as updates on all the major components. Noteworthy changes are a significant reduction in the target for the optimal (cost-beneficial) temperature path, a lower cost of reaching the 2 °C target, an analysis of the impact of the Paris Accord, and a major increase in the estimated social cost of carbon. [ABSTRACT FROM AUTHOR]

Development of low-cost, efficient, and stable oxygen evolution electrocatalysts is crucial for the conversion and storage of renewable energy. Therefore, an effective integrated heterostructure catalyst is needed to achieve a lower overpotential during oxygen evolution process. In this paper, cobalt-zinc bimetallic MOF precursors are used as templates to prepare bimetallic cobalt-based selenides with good oxygen evolution catalytic activity and stability on carbon fiber paper. Due to the high specific surface area and porous structure of the coupling structure of nanorods and polyhedra, and the strong electronic coupling between CoSe 2 and ZnSe on nanorods. CoSe 2 -ZnSe/CP exhibits excellent electrocatalytic activity in 1 M KOH solution. It only requires an overpotential of 275 mV to reach the current density of 10 mA cm-2, and the Tafel slope is 68.9 mV dec-1. In addition, after 12 h of continuous operation of CoSe 2 -ZnSe/CP, the activity decay of the catalyst is negligible. This work provides a method for the design of heterogeneous bimetallic selenide integrated oxygen evolution electrocatalysts. [Display omitted] • The CoSe 2 -ZnSe/CP catalyst is obtained by selenization of MOF precursor at high temperature. • The catalyst has unique nanorod-coupled polyhedral morphology and high specific surface area. • The strong electron coupling between CoSe 2 and ZnSe improves the oxygen evolution activity. • CoSe 2 -ZnSe/CP exhibits low overpotential, high exchange current density and fast kinetics. [ABSTRACT FROM AUTHOR]

X-ray spectroscopy is a valuable technique for the study of many materials systems. Characterizing reactions in situ and operando can reveal complex reaction kinetics, which is crucial to understanding active site composition and reaction mechanisms. In this project, the design, fabrication and testing of an open-source and easy-to-fabricate electrochemical cell for in situ electrochemistry compatible with X-ray absorption spectroscopy in both transmission and fluorescence modes are accomplished via windows with large opening angles on both the upstream and downstream sides of the cell. Using a hobbyist computer numerical control machine and free 3D CAD software, anyone can make a reliable electrochemical cell using this design. Onion-like carbon nanoparticles, with a 1:3 iron-to-cobalt ratio, were drop-coated onto carbon paper for testing in situ X-ray absorption spectroscopy. Cyclic voltammetry of the carbon paper showed the expected behavior, with no increased ohmic drop, even in sandwiched cells. Chronoamperometry was used to apply 0.4 V versus reversible hydrogen electrode, with and without 15 min of oxygen purging to ensure that the electrochemical cell does not provide any artefacts due to gas purging. The XANES and EXAFS spectra showed no differences with and without oxygen, as expected at 0.4 V, without any artefacts due to gas purging. The development of this open-source electrochemical cell design allows for improved collection of in situ X-ray absorption spectroscopy data and enables researchers to perform both transmission and fluorescence simultaneously. It additionally addresses key practical considerations including gas purging, reduced ionic resistance and leak prevention. [ABSTRACT FROM AUTHOR]

This paper analyses carbon emissions and value-added embodied in trade between two large developed countries, South Korea and the United States, during 2000-2014. Using multi-regional input-output (MRIO) tables, our analysis reveals that carbon emissions and value-added embodied in exports grew by 19% and 101% for South Korea but shrank by 43% and 7% for the United States. As a result, South Korea experienced a 40% increase in net carbon exports and 243% increase in net valueadded exports. At the industry level, the primary drivers of changes in carbon exports were electricity and basic materials. The majority of industries in witnessed improvements in carbon intensities suggesting improved environmental efficiency. While both countries achieved a decoupling of carbon emissions from value-added exports, substantial year-to-year and sectoral variations were observed. Finally, structural decomposition analysis indicates that domestic supply-side factors played a role in decreasing emissions whereas foreign demand-side factors contributed to emissions increases. In line with the main findings, various implications for policy and future research are discussed. [ABSTRACT FROM AUTHOR]

Carbon paper is commonly used for catalytic electrode preparation because of its high conductivity, corrosion resistance, and stability. However, traditional electrode preparation methods are inappropriate for highly hydrophobic carbon paper. In this paper, a high‐activity carbon paper catalytic electrode was prepared using multistrategies cold plasma modification to create atomic structural defects, dope N and Cu elements, and introduce oxygen‐containing functional groups. Analyses show that the bombardment of high‐energy particles caused atomic structural defects. Nitrogen and copper entered the carbon paper through plasma‐induced chemical recombination and physical adsorption, reaching 5.26% and 3.83%, respectively. Ethanol‐based plasma introduced oxygen‐containing functional groups to improve hydrophilicity. Finally, the plasma‐prepared electrode exhibited a reduction efficiency of 87.69% in an electrocatalytic nitrate reduction reaction. [ABSTRACT FROM AUTHOR]

Atomically dispersed catalysts are a promising alternative to platinum group metal catalysts for catalyzing the oxygen reduction reaction (ORR), while limited durability during the electrocatalytic process severely restricts their practical application. Here, we report an atomically dispersed Co-doped carbon−nitrogen bilayer catalyst with unique dual-axial Co–C bonds (denoted as Co/DACN) by a smart phenyl-carbon-induced strategy, realizing highly efficient electrocatalytic ORR in both alkaline and acidic media. The corresponding half-wave potential for ORR is up to 0.85 and 0.77 V (vs. reversible hydrogen electrode (RHE)) in 0.5 M H2SO4 and 0.1 M KOH, respectively, representing the best ORR activity among all non-noble metal catalysts reported to date. Impressively, the Zn–air battery (ZAB) equipped with Co/DACN cathode achieves outstanding durability after 1,688 h operation at 10 mA cm−2 with a high current density (154.2 mA cm−2) and a peak power density (210.1 mW cm−2). Density functional theory calculations reveal that the unique dual-axial cross-linking Co−C bonds of Co/DACN significantly enhance the stability during ORR and also facilitate the 4e− ORR pathway by forming a joint electron pool due to the improved interlayer electron mobility. We believe that axial engineering opens a broad avenue to develop high-performance heterogeneous electrocatalysts for advanced energy conversion and storage. [ABSTRACT FROM AUTHOR]

Microfluidic fuel cells (μFCs) offer a promising avenue for generating energy from glycerol, utilizing flow‐through electrodes to enhance reactant utilization. However, the cathodic reaction must efficiently consume the electrons harvested at the anode side to unlock its full potential. Here, we explore the feasibility of employing liquid oxidants as an alternative to O2 reduction on metal‐free carbon paper (CP) cathodes. We investigated the half‐cell reactions and the energy conversion in a new reusable 3D‐printed μFC. Half‐cell reactions predict spontaneous reactions by coupling glycerol electrooxidation in an alkaline medium with O2, Na2S2O8, and HClO from commercial bleach in an acidic medium. The μFC printed using the stereolithography apparatus technique build microchannels to place the Pt/C/CP anode and CP cathodes. The glycerol/Na2S2O8 μFC delivered a maximum of 32.4 mW cm−2, while glycerol/HClO μFC displayed 55.9 mW cm−2. This research sheds light on the potential of liquid oxidants as effective alternatives to O2 reduction, presenting a pathway toward optimizing μFCs and their practical applications in energy conversion from glycerol. [ABSTRACT FROM AUTHOR]

The surface properties of the anode porous transport layer (PTL) significantly impact the performance of a proton exchange membrane water electrolyzer (PEMWE). The pretreatment (ultrasonic cleaning and acid etching) of a pristine titanium (Ti) felt before it is used as the anode PTL and the surface structural modification of a PTL are two critical methods to improve the performance of an electrolyzer. However, the mechanisms for the pretreatment and surface modification need to be clarified. In this paper, five electrolyzers with five different-fabricated-ways anode PTLs are tested and compared based on I–V curves, EIS curves, and physical characterization techniques. X-ray photoelectron spectroscopy (XPS) results show that the ultrasonic cleaning pretreatment of PTL can improve hydrophilicity by increasing the amount of hydroxyl. In addition, EIS results indicate the significant charge transfer resistance of electrolyzer taking pristine titanium felt as PTL. Adopting the carbon paper as a microporous layer (MPL) or treated titanium felt with acid etching can eliminate or reduce the charge transfer resistance of the electrolyzer. Finally, the mechanism of surface pretreatment and modification of PTL are disclosed to cast light on the improvement of PTLs in further study. • Mechanisms of pretreatments and surface modifications for PTLs are investigated. • Electrolyzers with different-fabricated-ways anode PTLs are tested and compared. • Ultrasonic cleaning strengthens the hydrophilicity of the PTL. • Supplementing MPL or acid pretreatments can improve the anode charge transfer. • Improved mass and electron transport are the reasons for the improved performance. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

The development of effective and inexpensive electrocatalysts for hydrogen evolution reaction (HER) plays a key role in future energy system. Herein, we report a series of NiS x composited with polypyrrole (PPy) hollow nanospheres on carbon papers (CPs) to promote the HER performance. The crystal phase and lattice configuration of the in-situ grown NiS x can be tuned through unipolar pulse electrodeposition. The PPy with high conductivity is conducive to prevent the NiS x from collapse and improve the stability of the HER. As a result, the optimized Ni 3 S 2 /PPy/CP electrode manifests a low overpotential of 149 mV (vs. RHE) at 10 mA cm−2, an exceptional long-term stability over 100 h, and a large electrochemically active surface area of 1173.75 cm2. Furthermore, it is found that the exposure of (110), (122) and (300) planes of Ni 3 S 2 facilitates to increase the number of active sites. The precise lattice regulation contributes to achieve high HER performance. [Display omitted] • A series of NiS x /PPy/CP composite electrocatalysts were prepared for HER. • The crystalline phase of NiS x can be tuned by controlling the lattice structure. • The (110), (122) and (300) lattice planes of Ni 3 S 2 provide rich active sites for HER. • The optimal Ni 3 S 2 /PPy/CP showed a low overpotential of 149 mV at 10 mA cm−2. • PPy is able to protect active substance from loss and improve long-term stability. [ABSTRACT FROM AUTHOR]

Currently, developing highly active and low-cost electrocatalytic materials for oxygen evolution reaction (OER) is an enormously grand challenge. Herein, we developed a novel and highly active Mn doped Co 2 Fe layer double hydroxide (LDH) electrocatalyst for OER. We discovered that these electrocatalytic materials can be directly grown on carbon papers to construct high-specific-surface-area electrode, which shows the lowest overpotential of 266 mV at 10 mA cm−2. Furthermore, after introducing Mn element, DFT + U calculation found that the ∗OOH of Fe-site on Co 2 Fe 0.67 Mn 0.33 LDH could draw more electrons than Co 2 Fe LDH due to the electronegativity differences between Fe-site on Co 2 Fe 0.67 Mn 0.33 LDH and Fe-site on Co 2 Fe LDH, which is reason that the energy level of Fe 3d (e g) was obviously downshifted by d-d repulsion of Mn 3d and Fe 3d in the neighboring sites of Co 2 Fe 0.67 Mn 0.33 LDH after doped Mn element, which leads to reduce charge-transfer energy from O 2p to Fe 3d (e g) to promote oxygen evolution processes for OER. Meanwhile, the band gap is also decreased after doped Mn element in Co 2 Fe LDH due to the downshifted e g orbital energy of Fe 3d. This study gives a general avenue to design and developing efficiently active LDH electrocatalysts for OER in the future. • Both bimetallic CoFe LDH and Mn doped CoFe LDHs directly grown on carbon paper are successfully synthesized. • The Co 2 Fe 0.67 Mn 0.33 LDH@NFs exhibits a small overpotential of 236 mV at 10 mA cm−1 for OER. • DFT + U studies reveal that the observed superb OER activity could be attributed to d-d repulsion of Mn 3d and Fe 3d. [ABSTRACT FROM AUTHOR]

Carbon paper is one of the most widely used gas diffusion layer substrate materials due to its stable performance, relatively low cost, and easy for subsequent processing. Water-soluble phenolic resin, which is more ecologically friendly than alcohol-soluble phenolic resin, was used to prepare carbon paper as the precursor of the carbon matrix. And the effect of different resin solution concentrations on the properties of carbon paper was explored. The results showed that the graphitization, electrical conductivity and mechanical properties of carbon paper increased with the increase of resin solution concentration. When the concentration of resin solution was 20 wt%, the performance of carbon paper was relatively optimal. The graphitization of the carbon paper reached 65.45%, the porosity reached 80.74%, the resistance value at 1 MPa pressure was only 7.61 mΩ cm2, the tensile strength was 1.57 MPa, and the elastic modulus was 1210.98 MPa. [ABSTRACT FROM AUTHOR]

Carbon paper as a macroporous substrate of gas diffusion layer in proton exchange membrane fuel cells directly impacts the output performance of cells. In this study, we present a straightforward strategy to improve the overall performance of carbon paper by mixing short/long (6mm/10 mm) chopped carbon fibers at an optimal concentration of phenolic resin. The results show that incorporating longer carbon fibers can increase the porosity, conductivity, gas flux, and mechanical properties of carbon paper. The membrane electrode assembly achieved a peak power density of 1182.61 mW cm−2 at 60% RH using carbon paper with a long carbon fiber content of 40 wt% and an impregnation concentration of 10 wt%. This outperforms commercially available carbon paper. Based on electrochemical impedance spectroscopy results, it was confirmed that our carbon paper had a lower mass transfer resistance of only 32.17 mΩ cm−2 under conditions of 2 A cm−2 and 60% RH. This was due to its sparser three−dimensional network-like pore structure which was created by mixing different lengths (6mm/10 mm) of carbon fibers. This work provides new insights into preparing high−performance carbon papers. • The nature of carbon paper is regulated by mixing short/long (6mm/10 mm) CFs ratio. • The long carbon fiber contents of 20–40 wt% present better physical properties. • The optimal carbon papers can mitigate mass transfer resistance. • MEA composed of the optimal CP shows a higher power density than commercial CP. [ABSTRACT FROM AUTHOR]

The Proton Exchange Membrane Fuel Cell (PEMFC) performances are strongly impacted by the compression of the Gas Diffusion Layer (GDL). Despite its fibrous microstructure, this material is usually considered as a continuous medium and characterized with uniform loading. However, the GDL is subjected to a heterogeneous compression onto rib/channel patterns in the fuel cell assembly. In the present study, a complex behavior of the GDL response is experimentally revealed when the material is loaded with a rib/channel pattern, compared to uniform compression. The tests are simulated by finite element modeling using a classical strain-dependent elastic law, using parameters fitted from uniform compression experiments. It is shown that the numerical results do not reproduce the effect of pattern observed experimentally. Hypotheses to interpret these results involve mechanisms at the fiber microscale including fiber fracture, cross-link breakage and fiber rearrangement, which are exacerbated by larger material deformation caused by the heterogeneous loading. • Unexpected impact of rib/channel patterns on GDL compression. • Experimental investigation of the effect of rib/channel width on GDL deformation. • Numerical study with classical model unable to reproduce experimental results. • Interpretations based on mechanisms at the fiber microscale. [ABSTRACT FROM AUTHOR]

A facile method is proposed in this work to prepare a carbon paper (CP) with outstanding properties by doping boron to catalyze graphitization at lower temperature. Boron was introduced into CP by impregnating carbon fiber preform into a boron/phenolic resin/ethanol solution, and then CP was obtained after the consecutive procedures of hot pressing, carbonization, and graphitization. Morphology, microstructure, composition, and physical properties of the doped and undoped CPs were thoroughly investigated via various techniques to exam the effects of boron concentration and graphitization temperature. Furthermore, the boron doped CP was fabricated into fuel cell gas diffusion layer (GDL) and membrane electrode assembly (MEA) to evaluate its performance through the single cell performance. The findings indicated CP doping with 2 wt% boron could lower the graphitization temperature by at least 200 °C. The B-doped GDL had a higher power density in comparison with the undoped GDLs made in our lab or from the commercial brands. • The innovative preparation method for carbon paper with high conductivity. • The effect of boron concentration and graphitization temperature on carbon paper. • The single cell performance of B-doped gas diffusion layer. [ABSTRACT FROM AUTHOR]

Carbon dots have been widely noticed due to their excellent optical properties, such as good photostability and a wide excitation wavelength range. However, the emission peaks of most known carbon dots (CDs) are in the blue region, which hinders their extensive applications in long‐wavelength emission. In this study, red‐emitting carbon dots (RCDs) that are pH‐responsive are synthesized using citric acid and urea as precursors, and their fluorescence intensity increased gradually with increasing solution pH from 1 to 12. A new mechanism based on H aggregation and Fermi energy level transfer is proposed to explain the pH‐responsive emission of RCDs. In contrast to the narrow response range of most pH‐sensitive CDs reported so far, the pH‐responsive range of RCDs is large, especially in the alkaline range, and their pronounced red light emission is well visualized. The prepared carbon dots have the advantages of non‐toxicity, low cost, and a wide pH response range. In addition, "rose" test paper and carbon dot PVA composite film, RCDs‐PVA film, are made to demonstrate the visualization of carbon dots in pH detection. The "rose" test paper and carbon dot PVA still have good fluorescence intensity. The prepared carbon dots have good application prospects for pH detection. [ABSTRACT FROM AUTHOR]

In this paper, by a simple hydrothermal method vertically aligned ZnO nanorod arrays were grown on the carbon fiber paper (CFP) and then through a facile chemical bath deposition method CuO nanosheets were loaded on ZnO nanorod arrays, following by thermal spraying method, carboxylated carbon nanotubes (CCNTs) were successfully integrated with CuO/ZnO@CFP to form a binder-free CuO/ZnO-CCNT@CFP sensor. The sensor shows enhanced sensing activity for baicalein and luteolin determination due to the improved structural integration and synergism of different electrode material components. Remarkably, the CuO/ZnO-CCNT@CFP sensor showed good linear relationships over wide concentration ranges of 0.03–0.70 µM and 0.70–20 µM for baicalein and 0.03–0.45 µM and 0.45–8.5 µM for luteolin detection, with the detection limits of 1.7 nM for baicalein and 0.5 nM for luteolin, respectively. More importantly, the CuO/ZnO-CCNT@CFP sensor was utilized in the simultaneous determination of baicalein and luteolin, delivering linear ranges of 0.4–14 µM (baicalein) and 0.2–6 µM (luteolin) with the limit of detection of 0.05 µM and 0.03 µM, respectively. In addition, the developed CuO/ZnO-CCNT@CFP electrode was further investigated to detect baicalein and luteolin in traditional herbal medicine samples, showing satisfied results in comparison with analytic results from high performance liquid chromatography. [ABSTRACT FROM AUTHOR]

Creatinine is one of the most important biomarkers to detect renal failures. The electrochemical detection of creatinine has been performed using complex enzymatic and non-enzymatic electrode arrays hindering their commercialization. In this work, a new and practical non-enzymatic electrochemical sensor was fabricated depositing copper on carbon paper electrodes by physical vapor deposition (namely Cu/CP). Surface and cross-sectional SEM images demonstrated the deposition of copper over the 3D structure of carbon paper. A thin film was found on the surface, while Cu nanowires with diameters of 180 ± 30 nm were found inside the 3D structure of CP. The thickness of the Cu film on the tubular structures of CP was of 390 ± 40 nm. High-resolution TEM images indicated that the Cu film was integrated by hierarchical structures containing terminal Cu hemispheres of 17.6 ± 2.2 nm. Additionally, interplanar distances from the selected-area electron diffraction pattern demonstrated the presence of Cu0, while Cu2O was also found. Creatinine concentrations in saliva between 16 and 400 µM indicate kidney failure. The Cu/CP electrochemical sensor detected creatinine with linear concentration ranges from 0 to 1000 µM with a r2 = 0.9936. Outstandingly, this sensor presented good reproducibility (RSD = 7.3%), and selectivity to detect creatinine in artificial saliva using interferents like urea, glucose, glycine, ascorbic and uric acids. [ABSTRACT FROM AUTHOR]

The preparation of graphene materials from biomass resources is still a challenge, even more so if they are going to be employed as supports for electrocatalysts for water splitting. Herein, we describe the preparation and characterization of graphene oxides (GOs) from solid macroalgae waste obtained after processing an agar–agar residue. The structural and morphological characterization of the obtained GO confirm the presence of a lamellar material that is composed of few layers with an increased number of heteroatoms (including nitrogen) if compared with those observed in a GO obtained from graphite (reference). Three-dimensional electrodes were prepared from these GOs by depositing them onto a fibrous carbon paper, followed by electrodeposition of the catalyst, NiFe. The electrocatalytic performance of these hybrid systems for the oxygen evolution reaction (OER) showed a proactive effect of both graphene materials toward catalysis. Moreover, the electrode prepared from the algae-based graphene showed the highest electrocatalytic activity. This fact could be explained by the different structure of the algae-based graphene which, due to differences in the nucleation growth patterns and electroactive sites developed during the electrodeposition process, produced more reactive NiFe species (higher oxidation state). [ABSTRACT FROM AUTHOR]

Skin-based wearable devices have gained significant attention due to advancements in soft materials and thin-film technologies. Nevertheless, traditional wearable electronics often entail expensive and intricate manufacturing processes and rely on metal-based substrates that are susceptible to corrosion and lack flexibility. In response to these challenges, this paper has emerged with an alternative substrate for wearable electrodes due to its cost-effectiveness and scalability in manufacturing. Paper-based electrodes offer an attractive solution with their inherent properties of high breathability, flexibility, biocompatibility, and tunability. In this study, we introduce carbon nanotube-based paper composites (CPC) electrodes designed for the continuous detection of biopotential signals, such as electrooculography (EOG), electrocardiogram (ECG), and electroencephalogram (EEG). To prevent direct skin contact with carbon nanotubes, we apply various packaging materials, including polydimethylsiloxane (PDMS), Eco-flex, polyimide (PI), and polyurethane (PU). We conduct a comparative analysis of their signal-to-noise ratios in comparison to conventional gel electrodes. Our system demonstrates real-time biopotential monitoring for continuous health tracking, utilizing CPC in conjunction with a portable data acquisition system. The collected data are analyzed to provide accurate heart rates, respiratory rates, and heart rate variability metrics. Additionally, we explore the feasibility using CPC for sleep monitoring by collecting EEG signals. [ABSTRACT FROM AUTHOR]

Electric‐driven conversion of carbon dioxide (CO2) to carbon monoxide (CO) under mild reaction conditions offers a promising approach to mitigate the greenhouse effect and the energy crisis. Surface engineering is believed to be one of the prospective methods for enhancing the electrocatalytic activity of CO2 reduction. Herein, hydroxyl (OH) groups were successfully introduced to cadmium nanosheets to form cadmium and cadmium hydroxide nanocomposites (i. e. Cd/Cd(OH)2 nanosheets) via a facile two‐step method. The as‐prepared Cd/Cd(OH)2/CP (CP indicates carbon paper) electrode displays excellent electrocatalytic activity for CO2 reduction to produce CO. The Faradaic efficiency of CO reaches 98.3 % and the current density achieves 23.8 mA cm−2 at −2.0 V vs. Ag/Ag+ in a CO2‐saturated 30 wt% 1‐butyl‐3‐methylimidazole hexafluorophosphate ([Bmim]PF6)‐65 wt% acetonitrile (CH3CN)‐5 wt% water (H2O) electrolyte. And the CO partial current density can reach up to 71.6 mA cm−2 with the CO Faradaic efficiency of more than 85 % at −2.3 V vs. Ag/Ag+, which stands out against Cd/CP, Cd(OH)2/CP, and Cd/CdO/CP electrodes. The excellent electrocatalytic performance of the Cd/Cd(OH)2/CP electrode can be attributed to its unique structural properties, suitable OH groups, perfect interaction with electrolyte, abundant active sites and fast electron transfer rate. [ABSTRACT FROM AUTHOR]

Waste wood, which has a large amount of cellulose fibers, should be transformed into useful materials for addressing environmental and resource problems. Thus, this study analyzed the application of waste wood as supercapacitor electrode material. First, cellulose fibers were extracted from waste wood and mixed with different contents of graphene nanoplatelets (GnPs) in water. Using a facile filtration method, cellulose papers with GnPs were prepared and converted into carbon papers through carbonization and then to porous activated carbon papers containing GnPs (ACP−GnP) through chemical activation processes. For the morphology of ACP−GnP, activated carbon fibers with abundant pores were formed. The increase in the amount of GnPs attached to the fiber surfaces decreased the number of pores. The Brunauer–Emmett–Teller surface areas and specific capacitance of the ACP−GnP electrodes decreased with an increase in the GnP content. However, the galvanostatic charge–discharge curves of ACPs with higher GnP contents gradually changed into triangular and linear shapes, which are associated with the capacitive performance. For example, ACP with 15 wt% GnP had a low mass transfer resistance and high charge delivery of ions, resulting in the specific capacitance value of 267 Fg−1 owing to micropore and mesopore formation during the activation of carbon paper. [ABSTRACT FROM AUTHOR]

This work investigates the optimization of carbon-based electrodes employed in bio-electrochemical systems (BES) through the deposition of nanostructured layers of poly(3,4-ethylene-dioxy-thiophene) poly(styrene-sulfonate) (PEDOT:PSS) on commercial carbon paper electrodes via ultrasonic spray coating (USC). This innovative application of USC demonstrated that uniform and controlled depositions of PEDOT:PSS can be successfully performed on carbon-based electrodes. To this end, the morphology and spatial uniformity of depositions were verified via scanning electron microscopy and Raman spectroscopy. Electrochemical characterizations of fabricated electrodes demonstrated a more than two-fold increase in the electrochemical active surface area with respect to bare carbon paper. A lab-scale experiment on BES was performed, selecting microbial fuel cells (MFCs) as the reference devices. Devices featuring USC-deposited PEDOT:PSS electrodes showed a three-fold-higher energy recovery with respect to control cells, reaching a maximum value of (13 ± 2) J·m−3. Furthermore, the amount of PEDOT:PSS required to optimize MFCs' performance is in line with values reported in the literature for other deposition methods. In conclusion, this work demonstrates that USC is a promising technique for application in BES. [ABSTRACT FROM AUTHOR]

Zinc nanoparticles were electro-deposited along the fibres of carbon paper (CP) substrate uniformly in a salt-induced pre-phase separation region solution. The as-prepared Zn/CP electrode was used for electro-reduction of CO 2 and exhibited a Faradaic efficiency towards CO of 97.6% with a current density of 340 mA cm−2 in an H-type cell, which is the best result to date. [Display omitted] Efficient electrode design is crucial for the electrochemical reduction of CO 2 to produce valuable chemicals. The solution used for the preparation of electrodes can affect their overall properties, which in turn determine the reaction efficiency. In this work, we report that transition metal salts could induce the change of two-phase ionic liquid/ethanol mixture into miscible one phase. Pre-phase separation region near the phase boundary of the ternary system was observed. Zinc nanoparticles were electro-deposited along the fibres of carbon paper (CP) substrate uniformly in the salt-induced pre-phase separation region solution. The as-prepared Zn(1)/CP electrode exhibits super-wettability to the electrolyte, rendering very high catalytic performance for CO 2 electro-reduction, and the Faradaic efficiency towards CO is 97.6% with a current density of 340 mA cm −2, which is the best result to date in an H-type cell. [ABSTRACT FROM AUTHOR]

We utilize a coupled economy–agroecology–hydrology modeling framework to capture the cascading impacts of climate change mitigation policy on agriculture and the resulting water quality cobenefits. We analyze a policy that assigns a range of United States government’s social cost of carbon estimates ($51, $76, and $152/ton of CO2-equivalents) to fossil fuel–based CO2 emissions. This policy raises energy costs and, importantly for agriculture, boosts the price of nitrogen fertilizer production. At the highest carbon price, US carbon emissions are reduced by about 50%, and nitrogen fertilizer prices rise by about 90%, leading to an approximate 15% reduction in fertilizer applications for corn production across the Mississippi River Basin. Corn and soybean production declines by about 7%, increasing crop prices by 6%, while nitrate leaching declines by about 10%. Simulated nitrate export to the Gulf of Mexico decreases by 8%, ultimately shrinking the average midsummer area of the Gulf of Mexico hypoxic area by 3% and hypoxic volume by 4%. We also consider the additional benefits of restored wetlands to mitigate nitrogen loading to reduce hypoxia in the Gulf of Mexico and find a targeted wetland restoration scenario approximately doubles the effect of a low to moderate social cost of carbon. Wetland restoration alone exhibited spillover effects that increased nitrate leaching in other parts of the basin which were mitigated with the inclusion of the carbon policy. We conclude that a national climate policy aimed at reducing greenhouse gas emissions in the United States would have important water quality cobenefits. [ABSTRACT FROM AUTHOR]

A well-designed support material between catalyst and substrate can always significantly enhance the performance of an electrode on water oxidation. In this work, a functional Ni and N-doped carbon layer (NNC) was designed on carbon paper (CP) via pyrolysis by using a controlled electrodeposited polyporphyrin as a precursor. Consequently, the fabricated NiFe-LDH/NNC/CP achieved a catalytic current density of 100 mA cm−2 at a small overpotential of 231 mV with a low Tafel slope of 26.0 mV dec−1, as well as high durability for more than 360 h. The insights are that N-doping reinforces the hydrophilicity and the catalyst binding capacity, while Ni-doping intensifies the conductivity. [ABSTRACT FROM AUTHOR]

This study aims to exploit the distinctive properties of carbon nanotube materials, which are particularly pronounced at the microscopic scale, by deploying fabrication techniques that allow their features to be observed macroscopically. Specifically, we aim to create a semiconductor device that exhibits flexibility and the ability to modulate its electromagnetic wave absorption frequency by means of biasing. Initially, we fabricate a sheet of carbon nanotubes through a vacuum filtration process. Subsequently, phosphorus and boron elements are separately doped into the nanotube sheet, enabling it to embody the characteristics of a PN diode. Measurements indicate that, in addition to the fundamental diode's current–voltage relationship, the device also demonstrates intriguing transmission properties under the TEM mode of electromagnetic waves. It exhibits a frequency shift of approximately 2.3125 GHz for each volt of bias change. The final result is a lightweight and flexible carbon-based semiconductor microwave filter, which can conform to curved surfaces. This feat underscores the potential of such materials for innovative and effective electromagnetic wave manipulation. [ABSTRACT FROM AUTHOR]

Rationale: Rapid on‐site detection of persistent organic pollutants (POP) is highly desirable for environmental protection. Methods: Herein, a rapid on‐site analytical workflow was developed for the investigation of polycyclic aromatic hydrocarbons and perfluorinated compounds using multiwalled carbon nanotube–modified paper spray ionization (PSI) coupled with a miniature ion trap mass spectrometer. Critical parameters regarding PSI and miniature mass spectrometry analysis were optimized. Results: The analytical performance of the developed method was evaluated under optimized conditions, obtaining a short analysis duration of less than 1 min, sufficient linearity with correlation coefficients greater than 0.99, acceptable recovery rates of 93.1%–105.8% with relative standard deviations of between 3.5% and 10.3%, and reasonable sensitivity with limits of detection and quantitation of 2–200 and 5–500 μg/L, respectively. Conclusions: Considering these aspects, it was concluded that the present approach demonstrated a promising solution for rapid on‐site detection of emerging POPs. [ABSTRACT FROM AUTHOR]

China's rapid urbanization has led to the development of integrated transport networks, which requires the transport sector to pay particular attention to the integrated transport comprehensive carrying capacity (ITCCC). Concurrently, global climate change has focused the world community's attention on greenhouse gas concentrations like CO2. This study establishes an ITCCC measurement model of urban agglomerations (UAs) and measures the comprehensive carrying capacity from four factors: socio-economic, basic resources, transport facilities, and traffic environment. In particular, this paper takes carbon emission as a critical indicator of the traffic environment when considering the impact factors of ITCCC. Based on the data of China's five major UAs, this study estimates carrying capacity levels with the ITCCC model and analyses regional characteristics using the spatial-temporal differentiation method. The results show that the traffic environment significantly impacts the ITCCC. Further low-carbon transport policies and measures are recommended to achieve sustainable development of integrated transport in UAs. [ABSTRACT FROM AUTHOR]

Carbon fibers (CFs) cannot be directly used for the preparation of CF paper because of their chemically inert nature. Herein, the surface of CFs was modified using the spontaneous oxidative self-polymerization of dopamine. By taking full advantage of the spontaneous oxidation and self-polymerization properties of PD to maintain the maximum strength of CFs, a polydopamine-modified CF paper (PDA-CFP) with excellent performance was prepared using PD-modified CFs (PDA-CFs). This increased the proportion of hydrophilic functional groups on the surface of carbon fibers, increased the O/C ratio on the CF surface by 6 times, and improved the bond strength between the modified CF and the adhesive by making full use of the interaction force between polydopamine and PVA fibers. In this way, the primary properties of the CF paper were improved. Overall, the results showed that the dispersion of CF was considerably improved with dopamine modification. In addition, the primary physical properties of PDA-CFP were better than those of virgin CF paper (CFP-0). PDA-CFP exhibited a maximum tensile strength of 2.04 kN·m−1, a minimum resistivity of 0.06055 Ω·cm−1, and a minimum porosity of 72.4%. The tightness was increased by up to 12.1%. [ABSTRACT FROM AUTHOR]

The large-scale implementation of renewable energy systems necessitates the development of energy storage solutions to effectively manage imbalances between energy supply and demand. Herein, we investigate such a scalable material solution for energy storage in supercapacitors constructed from readily available material precursors that can be locally sourced from virtually anywhere on the planet, namely cement, water, and carbon black. We characterize our carbon-cement electrodes by combining correlative EDS-Raman spectroscopy with capacitance measurements derived from cyclic voltammetry and galvanostatic charge-discharge experiments using integer and fractional derivatives to correct for rate and current intensity effects. Texture analysis reveals that the hydration reactions of cement in the presence of carbon generate a fractal-like electron-conducting carbon network that permeates the load-bearing cement-based matrix. The energy storage capacity of this space-filling carbon black network of the high specific surface area accessible to charge storage is shown to be an intensive quantity, whereas the high-rate capability of the carbon-cement electrodes exhibits self-similarity due to the hydration porosity available for charge transport. This intensive and self-similar nature of energy storage and rate capability represents an opportunity for mass scaling from electrode to structural scales. The availability, versatility, and scalability of these carbon-cement supercapacitors opens a horizon for the design of multifunctional structures that leverage high energy storage capacity, highrate charge/discharge capabilities, and structural strength for sustainable residential and industrial applications ranging from energy autarkic shelters and self-charging roads for electric vehicles, to intermittent energy storage for wind turbines and tidal power stations. [ABSTRACT FROM AUTHOR]

A noble-metal-free bifunctional electrocatalyst with outstanding activity and stability is of great importance for the development of rechargeable zinc-air batteries (ZABs). Herein, we employed a facile strategy to fabricate nitrogen-doped NiCo 2 O 4 nanostructures on carbon paper as a binder-free air cathode for rechargeable ZABs. An optimized process of nitrogen plasma treatment has enhanced the electrical conductivity of the metal oxide and induced abundant active sites into the crystal structures, resulting in enhanced electrocatalytic activities toward oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Notably, mild plasma treatment leads to efficient N doping while the morphology and specific surface area of the catalyst both remain unchanged. The air cathode with NiCo 2 O 4 doped with nitrogen in 2 min plasma treatment and integrated into a zinc-air battery with liquid electrolyte provided a small charge-discharge voltage gap and distinguished cycling stability superior to the air cathode with noble-metal catalyst counterparts. Furthermore, the solid-state zinc-air battery with this material displays excellent stability with just a small increase of the charge-discharge voltage gap over 20 h of operation. This work illustrates the promising potential of plasma treatment in the fabrication of high-performance catalysts. • N-doped NiCo 2 O 4 was prepared by hydrothermal method and N 2 plasma treatment. • Mild plasma treatment leads to efficient N doping in NiCo 2 O 4. • NiCo 2 O 4 with N 2 plasma treatment of 2 min exhibits excellent OER/ORR performances. • N–NiCo 2 O 4 -2 min worked as a binder-free air cathode in Zn-air batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] Li-rich dual-phase Li-Cu alloy is a promising candidate toward practical application of Li metal anode due to its in situ formed unique three-dimensional (3D) skeleton of electrochemical inert LiCu x solid-solution phase. Since a thin layer of metallic Li phase appears on the surface of as-prepared Li-Cu alloy, the LiCu x framework cannot regulate Li deposition efficiently in the first Li plating process. Herein, a lithiophilic LiC 6 headspace is capped on the upper surface of the Li-Cu alloy, which can not only offer free space to accommodate Li deposition and maintain dimensional stability of the anode, but also provide abundant lithiophilic sites and guide Li deposition effectively. This unique bilayer architecture is fabricated via a facile thermal infiltration method, where the Li-Cu alloy layer with an ultrathin thickness around 40 μm occupies the bottom of a carbon paper (CP) sheet, and the upper part of this 3D porous framework is reserved as the headspace for Li storage. Notably, the molten Li can quickly convert these carbon fibers of the CP into lithiophilic LiC 6 fibers while the CP is touched with the liquid Li. The synergetic effect between the LiC 6 fibers framework and LiCu x nanowires scaffold can ensure a uniform local electric field and stable Li metal deposition during cycling. As a consequence, the CP capped ultrathin Li-Cu alloy anode demonstrates excellent cycling stability and rate capability. [ABSTRACT FROM AUTHOR]

The electrochemical detection of BPA often requires modification of electrodes to overcome BPA′s slower kinetics and higher oxidation potential. This work reports a modification‐free, paper electrode based on vacuum‐filtered SWCNT thin film. The prepared electrode does not need to be polished or transferred into the conducting substrates. The linear sweep voltammetric detection showed a linear response from 0.5–10 μM and 25–100 μM with the experimental LOD of 1.0 μM (S/N=3). The interference study and good recovery percentage (93–105 %) in real water samples demonstrated the method's selectivity. The sensor can be promising for developing a simple, low‐cost, portable, and paper‐based BPA monitoring system. [ABSTRACT FROM AUTHOR]

The formation of a cellular hierarchically organized NiO film on a carbon paper substrate under hydrothermal conditions using triethanolamine as a base has been studied. The thermal behavior of the carbon paper substrate with the applied semi-product shell was studied using synchronous thermal analysis (TGA/DSC) and it was demonstrated that such modification of the material surface leads to a noticeable increase in its thermal stability. Using scanning electron microscopy (SEM), it was shown that the NiO film grown on the carbon fiber surface is characterized by a complex cellular morphology, organized by partially layered individual nanosheets of about 4–5 nm thickness and lateral dimensions up to 1–2 μm, some edges and folds of which are located vertically relative to the carbon fiber surface. The surface of the obtained material was also examined using atomic force microscopy (AFM), and the electronic work function of the oxide shell surface was evaluated using the Kelvin probe force microscopy (KPFM) method. The electrochemical parameters of the obtained flexible NiO/CP electrode were analyzed: the dependence of the specific capacitance on the current density was determined and the stability of the material during cycling was studied, which showed that the proposed approach is promising for manufacturing hierarchically organized electrodes for flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Potassium vanadium fluorophosphate (KVPO4F) is regarded as a promising cathode candidate for potassium-ion batteries due to its high working voltage and satisfactory theoretical capacity. However, the usage of electrochemically inactive binders and redundant current collectors typically results in inferior electrochemical performance and low energy density, thus implying the important role of rational electrode structure design. Herein, we have reported a scalable and cost-effective synthesis of a cellulose-derived KVPO4F self-supporting electrode, which features a special surface hydroxyl chemistry, three-dimensional porous and conductive framework, as well as super flexible and stable architecture. The cellulose not only serves as a flexible substrate, a pore-forming agent, and a versatile binder for KVPO4F/conductive carbon but also enhances the K-ion migration ability. Benefiting from the special hydroxyl chemistry-induced storage mechanism and electrode structural stability, the flexible freestanding KVPO4F cathode exhibits high-rate performance (53.0% capacity retention with current densities increased 50-fold, from 0.2 C to 10 C) and impressive cycling stability (capacity retention up to 74.9% can be achieved over 1,000 cycles at a rate of 5 C). Such electrode design and surface engineering strategies, along with a deeper understanding of potassium storage mechanisms, provide invaluable guidance for better electrode design to boost the performance of potassium-ion energy storage systems. [ABSTRACT FROM AUTHOR]

The electrocatalytic hydrogenation of aromatic rings in benzoic acid derivatives has arisen as a notionally engaging substitute for thermal catalysis under mild conditions. However, the utilization of organic solvents and low faradaic efficiency are incompatible with the principles of green chemistry and energy conservation. Herein, bimetallic PtRu supported on carbon paper developed by co-electrodeposition with optimized atomic ratios maintains an inspiring high conversion of 92.9%, high selectivity of 100% and a high faradaic efficiency of 62.2% for the hydrogenation of benzoic acid to cyclohexanecarboxylic acid in an acidic aqueous electrolyte without external H2, which is the best result to date. The optimized electrocatalyst also exhibits outstanding stability and universality for the electrocatalytic hydrogenation of benzoic acid derivatives. In situ Raman results and theoretical calculations prove that the synergistic effect generated by Ru modifying the electronic structure of Pt simultaneously enhances the capture of benzoic acid molecules and interfacial active hydrogen species and lowers the reaction energy barrier. After adsorbing benzoic acid, more accumulation of electrons around the Ru atom reduces the electron density of phenyl, thereby activating the reaction. Meanwhile, the uniform alloy nanoclusters anchored to the carbon paper surface ensure highly efficient electronic transmission and high dispersion of active components, reducing excessive agglomeration. A proton-exchange membrane reactor is also used to certify the potential of the electrocatalytic hydrogenation of benzoic acid derivatives for large-scale application. [ABSTRACT FROM AUTHOR]

Recent progress in the in situ synthesise of various nanomaterials has gained tremendous interest and wide applications in various fields. For the first time to the best of our knowledge, this work reports a methodology of ultra-fast in situ synthesis of cobalt–cobalt oxide-reduced graphene oxide (Co−Co3O4−rGO (CC–rGO)) composite by laser ablation. The photothermal reduction technique was leveraged to develop the CC–rGO. For this, a low-cost 450 nm blue diode laser was irradiated onto a grade 1 filter paper in the presence of cobalt ions readily patterns the carbon matrix of paper to the composite material. Moreover, the variation of cobalt concentrations from 0.1–0.5 M led to structural and morphological changes. Standard techniques were adopted for thorough characterizations of developed sensor material for conductivity analysis, specific surface area, crystal-structural information, surface morphology, and chemical composition. The observed results were highly promoting towards the electrochemical sensing applications. Further, the developed sensor was found to be highly selective toward detecting a vital bio analyte alkaline phosphatase (ALP). The sensors performance was highly significant in the linear range of 10–800 mU l−1 with a detection limit of 10.13 mU l−1. The sensors applicability was further validated in actual human serum samples via a recovery-based approach. In the future, the developed in situ material methodology can begin a rapid composite material synthesis at a larger scale. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trimetallic NiCoFe PBAs are electrodeposited homogeneously on CFP as precursors. • The NiCoFe-Se NCs grown on CFP as self-supported electrode for OER. • The NiCoFe-Se/CFP exhibits remarkable OER activity and desirable stability. • Trimetallic element regulation effectively improves the OER activity of selenides. The progress of inexpensive, high-efficiency, and steady oxygen evolution reaction (OER) electrocatalysts is of great importance to promoting water splitting for green hydrogen production. Herein, tri-metallic NiCoFe selenide catalyst backed up by carbon fiber paper (CFP) was synthesized by a facile selenization of NiCoFe Prussian blue analogues (PBAs) for OER in alkaline solutions. The NiCoFe-Se/CFP inherited the porous nanostructure of the metal-organic frameworks (MOFs) precursors prepared by rapid cyclic voltammetry electrodeposition. Benefiting from the 3D hierarchical porous structure, optimized electronic structure of NiCoFe selenides and high conductivity, the synthesized electrocatalyst exhibits outstanding catalytic activity to the corresponding mono-metallic or bi-metallic selenides. Specifically, the NiCoFe-Se/CFP electrode demands an overpotential of 221 mV to attain the 10 mA cm−2 current density in 1.0 M KOH solution and a low Tafel slope of 38.6 mV dec-1. The prepared catalyst also displays good stability and durability. These findings prove a feasible strategy to further improve the catalytic activities of non-precious metal based OER electrocatalysts by the cooperation of structure design and chemical component modification. [ABSTRACT FROM AUTHOR]

Despite modern chemistry's success in providing affordable fertilizers for feeding the population and supporting the ammonia industry, ineffective nitrogen management has led to pollution of water resources and air, contributing to climate change. Here, we report a multifunctional copper single-atom electrocatalyst-based aerogel (Cu SAA) that integrates the multiscale structure of coordinated single-atomic sites and 3D channel frameworks. The Cu SAA demonstrates an impressive faradaic efficiency of 87% for NH3 synthesis, as well as remarkable sensing performance with detection limits of 0.15 ppm for NO3- and 1.19 ppm for NH4+. These multifunctional features enable precise control and conversion of nitrate to ammonia in the catalytic process, facilitating accurate regulation of the ammonium and nitrate ratios in fertilizers. We thus designed the Cu SAA into a smart and sustainable fertilizing system (SSFS), a prototype device for on-site automatic recycling of nutrients with precisely controlled nitrate/ammonium concentrations. The SSFS represents a forward step toward sustainable nutrient/waste recycling, thus permitting efficient nitrogen utilization of crops and mitigating pollutant emissions. This contribution exemplifies how electrocatalysis and nanotechnology can be potentially leveraged to enable sustainable agriculture. [ABSTRACT FROM AUTHOR]

Lithium sulfur batteries are suitable for drones due to their high gravimetric energy density (2600 Wh/kg of sulfur). However, on the cathode side, high specific capacity with high sulfur loading (high areal capacity) is challenging due to the poor conductivity of sulfur. Shuttling of Li-sulfide species between the sulfur cathode and lithium anode also limits specific capacity. Sulfur-carbon composite active materials with encapsulated sulfur address both issues but require expensive processing and have low sulfur content with limited areal capacity. Proper encapsulation of sulfur in carbonaceous structures along with active additives in solution may largely mitigate shuttling, resulting in cells with improved energy density at relatively low cost. Here, composite current collectors, selected binders, and carbonaceous matrices impregnated with an active mass were used to award stable sulfur cathodes with high areal specific capacity. All three components are necessary to reach a high sulfur loading of 3.8 mg/cm2 with a specific/areal capacity of 805 mAh/g/2.2 mAh/cm2. Good adhesion between the carbon-coated Al foil current collectors and the composite sulfur impregnated carbon matrices is mandatory for stable electrodes. Swelling of the binders influenced cycling retention as electroconductivity dominated the cycling performance of the Li-S cells comprising cathodes with high sulfur loading. Composite electrodes based on carbonaceous matrices in which sulfur is impregnated at high specific loading and non-swelling binders that maintain the integrated structure of the composite electrodes are important for strong performance. This basic design can be mass produced and optimized to yield practical devices. [ABSTRACT FROM AUTHOR]

Without excess Li, anode‐free Li‐metal batteries (AFLMBs) have been proposed as the most likely solution to realizing highly‐safe and cost‐effective Li‐metal batteries. Nevertheless, short cyclic life puzzles conventional AFLMBs due to anodic dead Li accumulation with a local current concentration induced by irreversible electrolyte depletion, insufficient active Li reservoir and slow Li+ transfer at the solid electrolyte interphase (SEI). Herein, SrI2 is introduced into carbon paper (CP) current collector to effectively suppress dead Li through synergistic mechanisms including reversible I−/I3− redox reaction to reactivate dead Li, dielectric SEI surface with SrF2 and LiF to prevent electrolyte decomposition and highly ionic conductive (3.488 mS cm−1) inner layer of SEI with abundant LiI to enable efficient Li+ transfer inside. With the SrI2‐modified current collector, the NCM532/CP cell delivers unprecedented cyclic performances with a capacity of 129.2 mAh g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]