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Tin-based sulfides, such as SnS2, have garnered attention as lithium-ion anode materials due to their layer structure and high conductivity capacity. However, during the lithium alloying/dealloying cycles, SnS2 material exhibits a rapid capacity decay due to the volume expansion, which hinders the application of SnS2. In this study, a heterostructure composite material anchored on exfoliated graphite, designated as nano SnS2S3/Sn3S4/FeS/Fe7S8 anchored on 15.0 wt% exfoliated graphite (FSS/G-15%), was synthesized by heating a mixture of inexpensive reducing agent Fe powder and SnS2 powder, followed by ball milling with 15.0 wt% commercial graphite. Experimental results demonstrated that FSS/G-15% had exhibited optimal overall Li+ storage performance, achieving approximately 1306.7, 1199.2, 1033.1, 882.3, 707.3, 507, 366.3, 255.6, and 203.5 mA hg−1 at current densities of 0.1, 0.2, 0.5, 1, 2, 4, 6, 8, and 10 Ag−1, respectively, surpassing the majority of SnS2-based anode materials. The simplicity and efficiency of the synthetic method may have potential implications in various fields in the future. [ABSTRACT FROM AUTHOR]

The development of inexpensive, highly effective and durable electrocatalysts for hydrogen production via water electrolysis is of paramount importance. Transition metal oxides, owing to their simplicity in preparation and cost-effectiveness, have been widely investigated, particularly cobalt, nickel, and manganese oxides. Inspired by the synergies of the ternary cathode materials of lithium-ion batteries (LiNixMnyCo1-x-yO2, NMC), a simple and feasible method was used to prepare a graphite plate as the support, and Ni and Mn were co-doped with Co3O4 as an efficient water decomposition catalyst. Experimental studies indicated that the 10% Ni and 10% Mn co-doped Co3O4 (Co2.4Ni0.3Mn0.3O4, CNM-811) exhibited the lowest overpotential in the oxygen evolution reaction (OER), with CNM-811 achieving an overpotential of 338 mV at 30 mA cm−2 in NaOH aqueous solution, the Tafel slope is 79.71 mV dec−1. In the hydrogen evolution reaction (HER), an overpotential of 190 mV was attained at 10 mA cm−2. In overall water splitting, a cell voltage of 2.048 V was achieved at 100 mA cm−2, which was superior to many analogous catalysts reported today. [ABSTRACT FROM AUTHOR]

As a new type of negative electrode material for SIBs, (iron germanium sulfide) Fe2GeS4 is considered a highly promising negative electrode material for SIBs owing to its high theoretical capacity, fast Na+ diffusion kinetics, and good thermal stability. In practical applications, it is crucial to synthesize the high-capacity/reversible nanostructured Fe2GeS4-based negative electrodes through an easily executable method. In this study, a two-step synthesis method to prepare nanostructured Fe2GeS4 anchored on graphite (Fe2GeS4/G-15%) was employed: the commercial FeS, S, and Ge powders were mixed and heated, and then graphite was added for ball milling. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that there is a strong interaction between the nanostructured Fe2GeS4 powder and the exfoliated graphite, forming a highly stable nanocomposite material, which is beneficial for improving the reversible charge-discharge performance of the material. When used as a negative electrode material for SIBs, the prepared Fe2GeS4/G-15% exhibited a capacity of 665.5 mAh g−1 during the second cycle at 0.1 A g−1 and could maintain a capacity of 519 mAh g−1 even after the 60th cycle. Considering the simple synthesis process employed in this study, it provides a reference for the production of high-performance Fe2GeS4-based negative electrode materials for SIBs. [ABSTRACT FROM AUTHOR]

To accelerate the low-carbon transformation of the power industry, a range of carbon emission reduction policies and technologies have emerged. However, the current China's carbon emissions trading (CET) policy is inadequate in encouraging power generation enterprises to take proactive measures towards emission reduction due to challenges like fixed and low carbon prices. The high proportion of renewable energy in electricity consumption also faces significant challenges due to the unpredictable nature of wind and PV energy. Therefore, this paper applies stepped CET mechanism, energy storage system (ES) system and carbon capture and storage (CCS) mechanism together to hybrid renewable energy system, aiming to study their synergistic carbon emission reduction effect. Firstly, the paper constructs the stepped CET model considering incentives and penalties. Secondly, the stepped CET model, ES system and CCS are jointly introduced into the hybrid renewable energy system. Finally, a scenario analysis is conducted to investigate the synergistic effect of various carbon emissions reduction policies and technologies in the operation of power generation systems. The results show that: i) compared with traditional CET, the stepped CET increases renewable energy consumption by 0.12% and reduces carbon emissions by 0.6%; ii) the introduction of stepped CET and ES equipment together consumes an additional 36.1% of renewable energy and reduces carbon emissions by 32.4%; iii) based on stepped CET model and ES equipment, the introduction of CCS system reduces carbon emissions by 29.4%. [ABSTRACT FROM AUTHOR]

Understanding the bond-cleavage ability of metal clusters is very important in various fields, such as catalysis and surface science. In this work, we performed density functional theory calculations on the first dehydrogenation process (also the key step) of methanol on Pt ( n = 1-3, q = 0, +1, −1) clusters in varied charge states using quantum chemical calculations. It is shown that methanol is adsorbed much more easily to the cationic Pt than to the neutral and anionic Pt . By contrast, the intrinsic bond cleavage barriers of both C-H and O-H on the cationic Pt are significantly higher than on Pt (the only exception is the C-H bond cleavage on Pt). Promisingly, injecting an electron to the neutral Pt to give Pt can greatly reduce the C-H/O-H bond scission barrier while maintaining appreciable adsorption energy. The charging effect can be nicely interpreted by the nature of the frontier orbitals of Pt . [ABSTRACT FROM AUTHOR]

The bridging Re-Xe-Re bond with a remarkable stability is firstly predicted. The average binding energies for Re-Xe bond in ReCp(PF)Xe with bridging Xe are calculated to be higher than that in ReCp(CO)Xe, ReCp(CO)(PF)Xe and ReCp(PF)Xe with terminal Xe. The interaction between two ReCp(PF) fragments provides an additional contribution for the stability of bridging Re-Xe-Re bond. Besides, the ReCp(PF)Xe isomers with bridging Xe are also stable in energy than the isomers with bridging PF. As the terminal Re-Xe bond was found to exist in experiments, the more stable bridging Re-Xe-Re bond might be existent under similar or even milder condition. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the inner phase of carbon nanotubes (CNTs) can not only change the properties of molecules inside the tube, but also enhance or restrain the SN2 reactions. Thus, the CNTs can be considered a form of solid solvent. In this paper, we study the [2+2] cycloaddition reaction between CH2O and PH3CH2 in the gas phase, benzene solution and inner phase of CNT using the density functional theory (DFT). The results indicate that the inner phase of CNT has little effect on the [2+2] cycloaddition reaction. This can be explained as that while taking the linear arrangement for SN2 reaction, the reactants do not possess the axial symmetry for the studied [2+2] cycloaddition reaction. Therefore, although the CNT has large axial polarizability, it can exert little influence on the [2+2] cycloaddition reaction. Our studies will be helpful for further understanding of the inner phase chemistry of CNTs. [ABSTRACT FROM AUTHOR]

In order to predict potential molecules with Pb≡C bonding, we investigated the potential energy surface of a tetra-atomic system [PbCN2] at the CCSD(T)//B3LYP level. We found that the linear isomer PbCNN possesses good thermodynamic and kinetic stability. The combined molecular orbital analysis, hydrogenation heat, bond energy and bond dissociation energy all proved that PbCNN is composed of Pb≡C triple bonding. [ABSTRACT FROM AUTHOR]