The Fe-Al coatings were prepared on the surface of 316L stainless steel plate and the inner surface of 316L tubes by pack cementation method. The effect of aluminizing agent ratio, temperature and time on the microstructure and phase composition of the Fe-Al coatings were investigated by Scanning electron microscopy (SEM), energy spectrum analysis (EDS) and X-ray diffractometer (XRD). The growth rate of coatings was measured for the planar samples and the inner wall of the tubes. The results showed that uniform Fe-Al coatings with good coherence to the substrate were obtained after aluminizing at 700~800^oC for 6 h. The higher growth rate of coating was achieved in the aluminizing agent with Fe-Al powder content of 75%. The aluminizing temperature has little effect on the phase compositions of the coatings obtained in the range of 700~800^oC. The prepared Fe-Al coating show double-layered structure, with the outer Al-rich layer mainly composed of FeAl toughness phase, and the inner elemental diffusion layer mainly composed of Fe₃Al phase. With the increasing time, the element diffusion is enhanced in the coating, which leads to dense and smooth coating surface. On the other hand, due to the enhanced element diffusion, some pores with 1-2μm diameter appears in the region near the interface between Al-rich layer and diffusion layer and the number of pores is increasing with time. The Fe-Al coating without pores at the interface of the 316L substrate was prepared on inner surface of 316L stainless steel tubes in the temperature range of 700~800^oC. After the same aluminizing process, the thickness of the coating grown on the inner tube surface is about 1.1~2.1 times of that on the plate surface. It can be explained by the smaller nuclei volume of coating nucleated on a curved surface than that on a flat surface, which result in the higher nucleation efficiency and faster growth rate of coating on the inner surface of tubes.

Polylactic acid (PLA) is a widely used biomass-derived polymer material. A significant amount of discarded polylactic acid is generated every year in the disposable product sector. Herein, a discarded PLA-based hard carbon was synthesized with discarded PLA as precursor, through cross-linking reaction with phosphoric acid and then followed by high-temperature carbonization. The results indicate that excessively lower carbonization temperature will result in unstable pore structure with lower stability. Higher carbonization temperature leads to loss innon-carbon elements and decrease in reversible specific capacity. The introduction of phosphorus (P) increases the spacing between the hard carbon lamellae to 0.37 nm. At carbonization temperature of 700^oC, the prepared discarded PLA-based hard carbon presents a honeycomb-like spherical framework with smaller specific surface area, and richer in high content of heteroatoms P and O, therefore exhibits the best electrochemical performance. By testing the assembled lithium-ion battery with electrode made of the acquired hard carbon, results show that by a current density of 100 mA/g, the specific capacity can reach 552 mAh/g; while for an initial Coulomb efficiency of 58.7% (324 mAh/g), the cycle stability is still excellent after 100 cycles. Besides, after multiple cycles at varying current densities, a reversible discharge capacity of 408 mAh/g is still maintained.

There are many hard primary phases in Al-Fe alloy, which are prone to stress concentration during deformation, leading to alloy fracture and significantly increasing the wire breakage rate of aluminum alloy wires. In order to break down the primary secondary phase in the alloy and refine the microstructure of the alloy, this paper introduces the so-called “Conform process” i.e. continuous extrusion process in the preparation of Al-0.5Fe alloy wires. Correspondingly the evolution of the microstructure and properties of Al-0.5Fe alloy were characterized by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and tensile testing machine. The results showed that after 1st pass, the tensile strength and EC of the alloy increased simultaneously, with the tensile strength increasing from 76.3 MPa to 90.2 MPa and the electric conductivity (EC) increasing from 62.0% IACS to 62.3% IACS; With the increase of conform passes, the tensile strength, EC, and equivalent size of the primary phase all show a decreasing trend. After 4th pass, the tensile strength decreases to 78.4 MPa, the EC decreases to 61.95% IACS, and the equivalent size of the primary phase decreases to 0.31 μm. Through comparative analysis of the microstructures, it was found that with the increase of Conform passes, the decrease of EC may be ascribed to the gradual decrease in size and area fraction of the secondary phase

Transition metal phosphide has not only metal-like conductive properties but good adsorption and catalytic conversion of polysulfide lithium. In this paper, the NiFeP/KB electrocatalyst grown by 2D nanosheet NiFeP on Ketjen Black ECP-600JD carbon black (KB) was prepared. The S/NiFeP/KB cathode material was obtained by mixing the nano sulfur particles with NiFeP/KB in a proportional and uniform way. Due to the synergistic effect of metal doping and hierarchical structure, the electrode prepared using S/NiFeP/KB material had a specific capacity of 1454.5 mAh/g at 0.1C for the first discharge, which remained 821.1 mAh/g after 200 cycles, 639.9 mAh/g after 300 cycles at 2C, and the capacity retention rate reached 74.7%. Further combined with CV and EIS tests, the NiFeP/KB electrocatalyst can effectively improve the oxidation and reduction reaction rate of lithium polysulfide in the battery, thus promoting the reaction kinetics of lithium and sulfur.

Mo-based amorphous alloys show excellent degradation performance and thermal stability in the field of dye wastewater degradation, and have efficient catalytic reactivity over a wide pH range. This paper successfully prepared novel MoFe-based (Mo₅₁Co₁₇Fe₁₇B₁₅ and Mo₅₁Fe₃₄B₁₅) amorphous alloy wires using the melt-spinning method. This further enhanced the catalytic activity of Mo-based amorphous alloys in extremely acidic media, and investigated the degradation performance of the two amorphous wire materials towards crystal violet solution and its reaction mechanism. The results show that Mo₅₁Co₁₇Fe₁₇B₁₅ and Mo₅₁Fe₃₄B₁₅ amorphous alloy wires can completely degrade crystal violet solution with pH 2~9. The degradation efficiency of Mo₅₁Fe₃₄B₁₅ is higher than that of Mo₅₁Co₁₇Fe₁₇B₁₅, and the time required for the former to reach the same degradation degree is only 1/2 of the latter. In addition, the Mo₅₁Fe₃₄B₁₅ amorphous alloy wires have a higher self-corrosion potential and lower corrosion current density, superior corrosion resistance and a higher surface Fe²⁺ content, which is conducive to providing a large number of electron transfer basis for the catalytic degradation process. The suitable corrosion behavior and faster electron transfer ability are the key reasons for its superior degradation performance.

The Fe-doped magnetic biochar FSBC _x-y was prepared via high temperature pyrolysis at 800^oC with Fe-doped carbon precursor as raw material. The Fe-doped carbon precursor was made via co-hydrothermal method with aloe green skin as carbon source and FeSO₄ as Fe source. The as-made FSBC _x-y was characterized by BET、SEM、FTIR、Zeta and XPS, and its application for adsorption of Ni²⁺ and Co²⁺ in waste water was investigated. The result showed that the FSBC _x-y has a hierarchical porous structure with a lamellar-like surface with many small flakes. When the mass ratio of aloe green skin to FeSO₄ was 3:1, the specific surface area of the as-made FSBC_3-1 is 82 m²·g^-1, and the total pore volume is 0.10 cm³·g^-1. The surface of FSBC_3-1 is rich in active groups of O, S and Fe, which can react with Ni²⁺ and Co²⁺ through ion exchange, electrostatic adsorption, complexation, co-precipitation and electrostatic adsorption. The adsorption isotherm and adsorption kinetics were more consistent with Langmuir model and pseudo-second-order kinetic model. According to the Langmuir model, the theoretical maximum adsorption capacities of Ni²⁺ and Co²⁺ by FSBC_3-1 are 136.43 mg·g^-1 and 132.10 mg·g^-1 respectively, which are mainly chemical adsorption. Fixed bed experiment results show that FSBC_3-1 has the high dynamic adsorption capacity for metal ions.

N and P co-doped graphene oxide (NPGO) was prepared by low temperature solution method with graphene oxide (GO) as raw material, phytic acid (PA) as P source, and aqueous ammonia solution (NH₃·H₂O) as N source, and then, N and P co-doped graphene/epoxy resin (NPGO/EP) waterborne composite coating was prepared by using waterborne epoxy resin (EP) as the film former. The structure and morphology of NPGO were characterized by FTIR, XPS, XRD, SEM and TEM. The corrosion resistance of composite coatings was assessed by contact angle measurement, electrochemical measurement and salt spray test. The results show that NPGO/EP composite coating has better metal protection effect than pure EP coating, GO/EP composite coating, as well as single P doped graphene/epoxy resin (PGO/EP) composite coating and single N doped graphene/epoxy resin (NGO/EP) composite coating. NPGO/EP composite coating showing good corrosion resistance when the addition amount of NPGO is 1.5% (mass fraction): the electrochemical impedance reaches 4.85 × 10⁸ Ω·cm², and slight rust marks appear only after 480 h of salt spray test.

A series of bi-functional catalysts (Cu-Co/X-MMT) were prepared via the impregnation method with oxide-pillared montmorillonite (X-MMT, X = SiO₂, Al₂O₃, ZrO₂, TiO₂) obtained from Na-montmorillonite (Na-MMT) as the solid acid, Cu as active component and Co as promoter. The acquired catalysts were characterized by XRD, N₂ adsorption-desorption at low temperature, NH₃-TPD, H₂-TPR, and XPS. The effect of different kinds of X-MMT on the steam reforming of dimethyl ether (SRD) reaction performance of the acquired bi-functional catalysts was investigated. The results show that the structure and acidity of X-MMT are significantly changed compared with Na-MMT, which is dependent on the type of oxide X, meanwhile, different X-MMT affects the particle size and reduction degree of copper, and thus influencing the SRD reaction performance of bi-functional catalysts. Among others, the Cu-Co/SiO₂-MMT bifunctional catalyst exhibits the best SRD performance, with the dimethyl ether conversion and H₂ yield reaching 80.3% and 57.3% under the conditions of 0.1 MPa, 350^oC and gas hour space velocity (GHSV) of 3000 mL/(g·h), respectively.