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Due to its suitable bandgap and excellent stability, 3C-SiC is being investigated as one of the promising candidates for photoelectrochemical (PEC) water oxidation. However, the limited surface activity and short carrier lifetime prevent 3C-SiC photoanodes from facilitating efficient PEC water splitting. To tackle these problems, this work proposes a plasma technique to control the crystal structure and optical characteristics of 3C-SiC. Nitrogen plasma induces carbon vacancies (Vc) and Si–N bonds, further leading to a narrower bandgap of 3C-SiC. The combination of Vc and N doping enhanced the light trapping capability of the electrode, thereby improving the efficiency of electron–hole pair separation and charge transfer, resulting in an accelerated water oxidation reaction, i.e., photocurrent density (2.50 mA cm−2 at 1.23 VRHE) increased by 7.6 times compared to that of pristine SiC. This work offers an effective strategy for regulating the electronic structure of SiC-based photoanodes by plasma treatment, which may be extended to other photoelectrodes for PEC application. [ABSTRACT FROM AUTHOR]

Transition metal nitrides (TMN) are promising material alternative to replace noble metals in the field of plasmonic applications, especially surface‐enhanced Raman spectroscopy (SERS). Here we demonstrate a practical surface enhanced Raman spectroscopy (SERS) substrate using zirconium nitride (ZrN) thin films grown by reactive gas‐timing (RGT) rf magnetron sputtering. The tailored properties of ZrN thin film exploited for SERS activity could be achieved to obtain a highly sensitive ZrN thin film SERS substrate with the enhancement factor (EF) of 1.24 × 106 and 4.8 %RSD at 1626 cm‐1 toward methylene blue (MB) analyte which are comparable to the optimized Au sputtered thin films (EF=1.18 × 106 and with 5.1%RSD). We find that the spatial plasmonic hotspots on the surface of ZrN SERS substrate controlled by the turn‐on timing of Ar:N2 sputtered gas sequence, leading to the discrete conductive surface profile, strongly relates to non‐stoichiometric composition and the degree of (200)‐oriented texture at the surface of ZrN thin film. Furthermore, ZrN thin film SERS substrates exhibit an excellent recyclability more than 30 cycles with simple cleaning process and a storage time longer than 6 months. The detection and reusability of ZrN SERS substrate on the low concentration of trinitrotoluene (TNT) for homeland security are also performed. [ABSTRACT FROM AUTHOR]

Rubber/nanocellulose composite sheets improve tensile properties compared with neat rubber sheets, when nanocellulose materials are suitably compounded with rubber matrices. First, two oven‐dried nanocellulose materials containing different additive components were prepared from nanocellulose/water dispersions, and the oven‐dried nanocellulose‐containing materials were compounded with rubber sheets under high shear forces by using a two‐roll mill. The tensile moduli and strength of the rubber/nanocellulose composite sheets were clearly better than those of the rubber sheet prepared without nanocellulose, while the elongations at break were similar. Thin films were cut from the rubber/nanocellulose composite sheets, and their real‐time tensile deformation processes were observed by transmission electron microscopy (TEM) to understand the time‐dependent patterns of crack propagation, void formations, and fusion between cracks and voids in the composites during tensile deformation. TEM observations showed that the composite sheets consisted of individual rubber/nanocellulose clusters. Voids initially formed inside the rubber/nanocellulose clusters, propagated to form cracks, fused with other voids or secondary cracks. There were slight differences between the crack‐propagation patterns of the two rubber composites, probably because of differences in the morphologies, sizes, distributions, and structures of the rubber/nanocellulose clusters, and surface chemical structures of individual nanocellulose elements between the composites. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous Zn/ZnSO4/MnO2 batteries, due to their high performance and safety, have attracted much attention as promising candidates for grid-scale energy storage. Despite intensive efforts in previous studies, the cathode electrochemistry remains largely unidentified. We observed new insights into the cathode electrochemistry in Zn/ZnSO4/MnO2 batteries and found that, regardless of the physicochemical states of manganese in the pristine, as-prepared cathode, birnessite is the fated compound. The birnessite consisted of both Mn(III) and Mn(IV) with Zn2+ as the foreign cation. Birnessite stores energy via chemical redox reactions. Mn(III) has the highest priority for discharge. Mn(IV) discharges stepwise, first to MnO–OH, and then MnO–OH continuously discharges to Mn2+. During recharge, birnessite is produced stepwise via Mn2+ → MnO–OH and MnO–OH → birnessite. Zinc sulphate hydroxide plays essential roles in driving discharge and recharge via its formation with hydroxyl ions (by-products of discharge) and via neutralization of proton ions (by-products of recharge). We inserted birnessite into three-dimensional networks of single-walled carbon nanotubes (3D-SWCNT-networks) via electrochemical deposition and the superior conductive properties of the birnessite/3D-SWCNT-networks have extended the cycling numbers of the rechargeable aqueous Zn/ZnSO4/MnO2 batteries over 11 000 with a capacity retention > 82.5% at a high discharge/recharge rate of 1.5 A g−1. The rechargeable aqueous Zn/ZnSO4/MnO2 batteries with birnessite/3D-SWCNT-networks as cathodes are the promising devices for applications in long-term energy storage. [ABSTRACT FROM AUTHOR]

Data science has been rapidly developed and implemented in diverse scientific and technological fields over the past decade, to accelerate new knowledge generation and develop high‐impact applications. Recently, different data science tools and techniques have been widely used, such as optimizations, regressions, and classifications of data (tabular, spectral, or visual). In this review, data science tools and techniques are discussed for their adoption for the synthesis, characterization, and applications of carbon‐based materials. Materials synthesis in conjunction with data science has resulted in optimal growth conditions with desired properties and processing techniques. Regarding characterization, molecular structures can be reconstructed using microscopy images, and a particular property can be predicted based on the other properties of the desired carbon material. Moreover, for the applications of carbon materials, data science has enabled prediction of the water treatment efficiency, classification of electronic signals, prediction of the biological activity, and virus classification. It is clear that by combining data science and carbon‐related materials, it is now possible to accelerate theory‐experimental research in the quest for novel materials and their emerging applications. [ABSTRACT FROM AUTHOR]

A resorcinol resin/water dispersion and a rubber latex are added to 1% 2,2,6,6,‐tetramethylpyperidine‐1‐oxyl (TEMPO)‐oxidized cellulose nanofibers (TEMPO‐CNFs) dispersed in water, followed by oven drying at 40 °C for 20 h to prepare a dried TEMPO‐CNF/resorcinol resin/latex rubber (DTRL) mixture with a weight ratio of 1/0.5/3. DTRL is then added to a nitrile‐butadiene rubber (NBR) or a carboxy group‐containing NBR (X‐NBR) sheet, and the mixture is kneaded by a two‐roll mill at 20–30 °C with high shear forces. The tensile strength and Young's modulus of the crosslinked DTRL/rubber composite sheets remarkably increased from 10 and 12 MPa, respectively, for the reference sheet to 24 and 82 MPa, respectively, for the DTRL/rubber composite sheets containing ≈10 vol% TEMPO‐CNFs. Scanning electron microscopy revealed that no TEMPO‐CNF agglomerates are present in the DTRL/rubber composite sheets. The tensile properties of the composite sheets are the best when a X‐NBR sheet and NBR latex are used as the matrix rubber and latex in DTRL preparation, respectively. When water‐extracted DTRL (WDTRL, mass recovery ratio ≈94%) is used in place of DTRL, the WDTRL/rubber composite sheets show sufficient water resistance, while the tensile properties are almost the same as those of the DTRL/rubber composite sheets. [ABSTRACT FROM AUTHOR]

Carbon solubility in the catalyst for the growth of graphene-type nanomaterials is an essential issue for their large-scale fabrication. Iron compounds are fundamental catalysts for the synthesis of carbon materials. The carbon solubility of ferrite (α-Fe) is ∼0.1% at 700 °C, which is enough to promote the growth of graphene nanomaterials. In this work, we synthesized crystalline multilayer graphene flakes (MLGFs) by a two-step catalytic chemical vapor deposition method using an α-Fe catalyst derived from the reduction of nanostructured hematite at 950 °C under an Ar–H 2 environment. In the first step, nitrogen-doped multi-walled carbon nanotubes were synthesized by a benzylamine-ferrocene mixture at 850 °C and oxidized at 620 °C in air. In the second step, the reduced nanostructured hematite was exposed to a mixture of a 1:9 benzylamine-1,2- dichlorobenzene at 950 °C. Raman spectroscopy confirmed the presence of MLGFs with a G band and a significant 2D band intensity. The results of the thermogravimetric analysis show that the maximum oxidation rate was at 643.5 °C. Additional functional density calculations were performed considering graphene growth on the oriented (110) α-Fe surface. This work reasserts the possibility of using alternative carbon sources for graphene growth. N-MWCNTs are oxidized in the air at a temperature of 620 °C to form nanostructured hematite (Fe 2 O 3), which is reduced at 950 °C under an Ar/H 2 flow to obtain nanostructured high carbon solubility γ-Fe. Then a nebulized mixture of benzylamine-1,2 dichlorobenzene flows to carbon-saturated it. Finally, by cooling producing the MLGFs. [Display omitted] • The use of nanostructured Fe-based catalyst for producing MLGFs. • Nebulized carbon precursors containing nitrogen and chloride atoms for synthesis MLGFs. • Electrochemical studies show MLGFs potential uses where extensive electron transfer capability is a necessary process. [ABSTRACT FROM AUTHOR]

Sponge-type nitrogen-doped multiwall carbon nanotubes (N-MWCNTs), synthesized via an aerosol-assisted catalytic chemical vapor deposition (AACCVD) method, were extensively studied. A ball-milled and oxidized red-leptosol (RL) was used as the catalyst precursor, and benzylamine worked as a carbon and nitrogen source. The ball-milled and oxidized RL increased their contact area and purity for the N-MWCNT synthesis. X-ray diffraction characterization revealed that raw RL contained kaolinite, quartz, graphite, hematite, and goethite. According to the electron microscopy analysis, the N-MWCNTs exhibited exotic morphologies and microstructures. The high-resolution X-ray photoelectron spectroscopy showed that the as-grown N-MWCNTs contained pyrrolic and pyridinic nitrogen species. The cyclic voltammetry studies demonstrated that the redox processes in the N-MWCNTs in 0.1 M H 2 SO 4 were dominated by the carboxyl, pyridinic, and pyrrolic groups. Using the natural RL as a catalyst precursor in AACCVD led to a large yield of N-MWCNTs mixed with different minerals, causing the observed morphologies and influencing the electrochemical behavior, which is of interest in energy-storage and sensing applications. Sponge-type nitrogen-doped multiwall carbon nanotubes (N-MWCNTs) synthesized by aerosol-assisted catalytic chemical vapor deposition using benzylamine as carbon and nitrogen sources and a red leptosol as a catalyst precursor. Cyclic voltammetry studies found pyrrolic-N, pyridinic-N, and oxygen groups as the leading chemical surface reactant groups for redox processes. [Display omitted] • A facile route to produce sponge-type nitrogen-doped multiwall carbon nanotubes using a low-cost red-leptosol as catalyst. • Soil minerals in red-leptosol enhance the yield of N-MWCNT. • The synthesized N-MWCNTs show promising properties for electrochemical devices. • CNT morphologies exhibit unusual structures. [ABSTRACT FROM AUTHOR]

Due to the special three-dimensional structures and excellent physicochemical properties, vertical graphene (VG) has been extensively investigated as potential material for supercapacitors. However, achieving VG-based supercapacitors with high-energy density and high-power density is a still tremendous challenge. Here we attempt to synthesize large-scale VG films on flexible substrates and design a novel battery-like supercapacitor (BSCs) with the VG on Ni foil (VG@Ni) as a binder-free electrode operating in the KOH electrolyte with the redox additives of K 3 Fe(CN) 6 and/or K 4 Fe(CN) 6. The VG@Ni electrodes demonstrate an ultrahigh areal capacitance of 1453 mF cm−2 at 5 mA cm−2 in 1 M KOH electrolyte with adding 0.07 M K 3 Fe(CN) 6 and 0.07 M K 4 Fe(CN) 6 , coulombic efficiency greater than 90%, and long-life cycling stability (capacitance retention is 99.3% after 20000 charge-discharge cycles). The BSCs, which are assembled with two identical VG@Ni electrodes, deliver the areal capacitance of 231 mF cm−2 with energy density of 32 μWh cm−2 and power density of 2498 μW cm−2 at 1 mA cm−2. These outstanding performances can be ascribed to the special feature and excellent properties of VG materials, high electronic conductivity of binder-free VG@Ni electrode, faradaic properties of redox electrolyte, and synergistic effects between the VG film and redox electrolyte. • Large-scale VG films are obtained on nickel and graphite foils by PECVD technique. • The VG films present excellent electrochemical performance in redox electrolyte. • The VG-based BSCs show high energy and power densities as well as long stability. [ABSTRACT FROM AUTHOR]