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To improve gas hydrate storage and transportation technology, ferromagnetic intermetallic compound NiMnGa particles with martensitic transformation endothermics were used to form micro/nanofluids with sodium dodecyl sulfate (SDS) to further strengthen the gas hydration process. In this work, the kinetic process of gas hydration in NiMnGa fluids with different concentrations (0, 0.1, 1, 2, and 3 wt.%) was investigated using a rotating magnetic field gas hydration separation experimental setup. The results show that the induction time of the 3 wt.% NiMnGa system was shortened by 98.3%, the gas consumption was increased by 50.5%, and the gas consumption rate was increased by 351.9% compared with the SDS system. Therefore, it is inferred from the mass transfer that NiMnGa micro/nanofluids can accelerate the formation of hydrates. [ABSTRACT FROM AUTHOR]

Combining the three-phase foam and simulated sea mud particle (SM-P: simulated sea mud particle) containing inert substances (SMTP: simulated sea mud three-phase foam) to engineer a new three-phase foam fire extinguishing material was a viable strategy to solve the problem of coal mine spontaneous combustion prevention and insufficient stability of mine fire extinguishing materials. Herein, based on constant temperature heating table and simulated coal spontaneous combustion fire extinguishing device, the experiments were conducted to evaluate the material properties. As expected, the SMTP-20 exhibited excellent stability (73.00 mins at 40 °C), which was 2.19 times that of ordinary three-phase foam (34.33 mins at 40 °C). The introduction of SM-P can also effectively reduce the thermal decomposition of powdered coal, the corresponding temperature of thermal decomposition peak value of raw coal was delayed 17.78 °C. The SMTP-20 could construct a thin fibrous-like foam layer with SM-P to cover the surface of burning coal and effectively seal cracks in the coal from oxygen contact, thereby preventing coal further oxidation. This work not only offers a new three-phase foam with outstanding performance, but also unravels a strategy for preparing three-phase foam with high stability and good fire extinguishing effect. [ABSTRACT FROM AUTHOR]

The formation of chemical bonds between metal ions and their supports is an effective strategy to achieve good catalytic activity. However, both the synthesis of active metal species on a support and control of their coordination environment are still challenging. Here, we show the use of an organic compound to produce tubular carbon nitride (TCN) as a support for Pd nanoparticles (NPs), creating a composite material (NP-Pd-TCN). It was found that Pd ions preferentially bind with the electron-rich N atoms of TCN, leading to strong metal-support interactions that benefit charge transfer from g-C3N4 to Pd. X-ray absorption spectroscopy further revealed that the metal-support interactions resulted in the formation of Pd-N bonds, which are responsible for the improvement in the charge dynamics as evidenced by the results from various techniques including photoluminescence (PL) spectroscopy, photocurrent measurements, and electrochemical impedance spectroscopy (EIS). Owing to the good dynamical properties, NP-Pd-TCN was used for photocatalytic hydrogen evolution under visible-light irradiation (λ > 420 nm) and an excellent evolution rate of ∼ 381 µmol·h−1 (0.02 g of the photocatalyst) was attained. This work aims to promote a strategy to synthesize efficient photocatalysts for hydrogen production by controllably introducing metal nanoparticles on a support and in the meantime forming chemical bonds to achieve intimate metal-support contact. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 into syngas, which can be used directly in the classical petroleum industrial processes, provides a powerful approach for achieving the recycling of anthropogenic carbon. Pd has previously been reported to be capable of converting CO2 into syngas with various CO/H2 ratios, but only at limited applied potential, which is mainly attributed to fewer active sites exposed toward electrocatalysis. Herein, high‐performance Pd nanomeshes (NMs) assembled with branch‐like Pd nanoparticles were designed and synthesized by using a simple interface‐induced self‐assembly strategy; these NMs could catalyze CO2‐into‐syngas conversion with a high current density in a wide applied potential range from −0.5 to −1.0 V (vs. reversible hydrogen electrode). Further evidence validated that the enhanced activity of the Pd NMs was not only caused by the crosslinked network structure accelerating electron transport, but also by the greater number of edge and/or corner active sites exposed on the surface of the NMs, which facilitated CO2 adsorption, CO2.− formation, COOH* stabilization, and CO generation. Under optimal operating conditions, Pd NMs could balance two competing reactions: CO2 reduction and hydrogen evolution. The resultant syngases with the ideal and tunable CO/H2 ratio between 0.5:1 and 1:1 could be used directly for methanol synthesis and Fischer–Tropsch reactions. [ABSTRACT FROM AUTHOR]

Developing cost-efficient electrocatalysts for oxygen evolution is vital for the viability of H energy generated via electrolytic water. Engineering favorable defects on the electrocatalysts to provide accessible active sites can boost the sluggish reaction thermodynamics or kinetics. Herein, CoS nanosheets were designed and grown on reduced graphene oxide (rGO) by controlling the successive two-step hydrothermal reaction. A belt-like cobalt-based precursor was first formed with the assistance of ammonia and rGO, which were then sulfurized into CoS by L-cysteine at a higher hydrothermal temperature. Because of the non-stoichiometric defects and ultrathin sheet-like structure, additional cobalt vacancies (V') were formed/exposed on the catalyst surface, which expedited the charge diffusion and increased the electroactive surface in contact with the electrolyte. The resulting CoS/rGO hybrids exhibited an overpotential as low as 310 mV at 10 mA·cm in an alkaline electrolyte for the oxygen evolution reaction (OER). Density functional theory calculations indicated that the V' on the CoS/rGO hybrid functioned as catalytic sites for enhanced OER. They also reduced the energy barrier for the transformation of intermediate oxygenated species, promoting the OER thermodynamics. [ABSTRACT FROM AUTHOR]

Establishing effective charge transfer channels between two semiconductors is key to improving photocatalytic activity. However, controlling hetero-structures in situ and designing binding modes pose significant challenges. Herein, hydrolytic SnCl 2 ·2H 2 O is selected as the metal source and loaded in situ onto a layered carbon nitriden supramolecular precursor. A composite photocatalyst, S 4 -Sn-N 2 , with electron pathways of SnS 2 and tubular carbon nitriden (TCN) is prepared through pyrolysis and vulcanization processes. The contact interface of SnS 2 -TCN is increased significantly, promoting the formation of S 4 -Sn-N 2 micro-structure in a Z-scheme charge transfer channel. This structure accelerates the separation and transport of photogenerated carriers, maintains the stronger redox ability, and improves the stability of SnS 2 in this series of heterojunctions. Therefore, the catalyst demonstrated exceptional photocatalytic hydrogen production efficiency, achieving a reaction rate of 86.4 µmol h -1 , which is 3.15 times greater than that of bare TCN., (© 2024 Wiley‐VCH GmbH.)

Designing and developing photocatalysts with excellent performance in order to achieve efficient hydrogen production is an important strategy for addressing future energy and environmental challenges. Traditional single-phase photocatalytic materials either have a large bandgap and low visible light response or experience rapid recombination of the photogenerated carriers with low quantum efficiency, seriously hindering their photocatalytic applications. To solve these issues, an important solution is to construct well-matched heterojunctions with highly efficient charge separation capabilities. To this end, an in situ sulfurization reaction was adopted after the deposition of Bi 3+ supramolecular complex on a layered supramolecular precursor of tubular carbon nitride (TCN). X-ray diffraction (XRD) patterns confirmed that the as-prepared sample has a good crystalline structure without any other impurities, while high-resolution transmission electron microscopy (HR-TEM) revealed that the heterojunction possesses a 2D structure with a layer of nano-array on its surface. Combined Fourier-transform infrared (FT-IR) spectra and energy-dispersive X-ray spectroscopy (EDX) revealed the interfacial interactions. Owing to the formation of the Z-scheme heterojunction, the visible light adsorption and the separation efficiency of the photo-generated carriers are both obviously enhanced, leaving the high energy electrons and high oxidative holes to participate in the photocatalytic reactions. As a result, the photocatalytic hydrogen evolution rate of Bi 2 S 3 -TCN achieves 65.2 μmol g -1 ·h -1 . This proposed green and environmentally benign route can also be applied to construct other sulfides with 2D TCN, providing some important information for the design and optimization of novel carbon-nitride-based semiconductors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Yuan, Yin, Xiang, Shao, Gao, Liu, Meng, Li, Xie, Xiao and Jiang.)

The electro-Fenton oxidation is one of the powerful approaches for achieving the complete mineralization of organic pollutants in water. The key dilemma for efficient industrial application of electro-Fenton oxidation is the complicated post-processing of iron sludge, and the cost and risk associated with H 2 O 2 transportation and storage. Herein, Cu-coupled Fe/Fe 3 C covered with carbon layer on carbon felt (Cu-Fe/Fe 3 C@C), engineered by a hydrothermal reaction followed by the consequent thermal-treatment in N 2 atmosphere, as a self-supported integrated cathode were used for an onsite oxygen reduction reaction and a Fenton oxidation reaction. Experimental evidences demonstrate that, at the operating potential of -1.1 V, Fe 3 C can selectively catalyze O 2 into H 2 O 2 by 2e reduction pathways with assistance of metal Cu. Meanwhile, metal Fe and Cu incorporated into Cu-Fe/Fe 3 C@C simultaneously motivate the onsite Fenton oxidation arose by H 2 O 2 . Such a win-win catalyst presented high activity in the electro-Fenton process. In acidic environment, the efficient mineralization rate of methylene blue, nitrobenzene, phenol, and bisphenol A can reach more than 70% in 60 min, as well as the excellent stability and durability due to the protection of graphited carbon layer. Compared with tradition electrochemical degrade system, the prepared Cu-Fe/Fe 3 C@C electrode as cathode for practical refractory brewing leachate treatment reveal more efficient decolorization and mineralization, saving 14.3% of electricity., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Electrochemical oxygen evolution reaction (OER) can be accelerated by employing transition-metal-based catalysts to obtain the desired activity and durability. Considering the promoting effect of the electrode structure on catalyzing OER, a stereo-film on carbon cloth comprising FeNi3 nanosheet-covered FeOOH (F@FeNi3-CC) was engineered by the hydrothermal reaction and subsequent synchronous electrodeposition of Fe and Ni ions. In F@FeNi3-CC, the FeOOH array not only provides the Fe source of FeNi3 nanosheets during the cathodic electrodeposition, but also functions as the support for the ultrathin FeNi3 nanosheets. Such a stereo-film with good electrolyte-permeability also offers expedited electrolyte/reactant transmission paths. The tailored FeNi3 nanosheet offers abundant exposed catalytic sites by virtue of the in situ derived hydroxide layer during anodic oxidation and also acts as the current collector to accelerate charge transport. The F@FeNi3-CC electrode yields outstanding catalytic activity towards OER in alkaline media, particularly at low potential of 1.50 V and large current density of 100 mA cm-2, accompanied with the excellent long-term stability. These results are significant for the construction of stereo-film electrodes for various engineering applications.

Manipulating the electrical conductivity and morphology of Co-based (hydr)oxides is significant for optimizing energy conversion in the oxygen evolution reaction (OER). Herein, 2D CoSe x nanocrystalline-dotted porous CoCo layered double hydroxide nanosheets (Co-Se NSs) were designed and synthesized via a modified in situ reduction and interface-directed assembly in an inert atmosphere. During the synchronous reduction/precipitation reaction between Co 2+ -oleylamine and NaHSe at the toluene-water interface, the hydrated Co-O and Co-Se clusters are generated and sequentially assemble under strong extrusion driven by the interfacial tension. Owing to the enriched vacancies on the lateral surfaces, the obtained loose and porous Co-Se NS presents low crystallinity. Moreover, electrons could spontaneously transfer from the CoCo LDH to the neighboring CoSe x nanocrystallites due to the stronger electron-withdrawing capability of metallic CoSe x , and thus more Co atoms in the CoCo layered double hydroxide (LDH) present a high oxidation state. This synergistic manipulation in the structure, component, and electron configuration of the Co-Se NS can increase the density of the OER active-sites, improve the electrical conductivity, and also offer a large accessible surface area and permeable channels for ion adsorption and transport. As a result, the resulting Co-Se NSs feature high catalytic activity towards OER, in particular a low onset potential of 1.48 V and an overpotential of only 290 mV at a current density of 10 mA cm -2 for the Co-Se-2 NS, as well as good stability in an accelerated durability test. The strategy developed here provides a reliable and valid way to synthesize multicomponent NSs, and is able to be extended to other areas of application.