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As an essential technology in metal additive manufacturing (AM), laser powder bed fusion (LPBF) has garnered significant attention owing to its unique capability to fabricate complex structural components with high design freedom, near-perfect density and enhanced mechanical properties. Herein, the influences of processing parameters on the microstructure characteristics and mechanical properties of LPBF-built AlSi10Mg samples are experimentally investigated, and a finite element model with multi-track laser scanning is developed to explore the effect of non-equilibrium solidification on the formation of metallurgical defects and microstructure evolution during LPBF process. The experimental results demonstrate that the tensile properties of LPBF-built samples can be significantly enhanced by decreasing the porosity level, and the optimized processing parameters yield an ultimate tensile strength (UTS) of 448 +/- 3 MPa and an elongation to failure of 8.3 +/- 0.9%. Analysis of predicted melting pool morphologies indicates that the formation mechanism of the melting pool is conductive melting, and the lack-of-fusion defects can be eliminated through the optimization of the overlap ratio between adjacent melting pools. Simulation results confirm that the cooling rate serves as a reliable indicator of alpha-Al cell size in the microstructure of LPBF-built AlSi10Mg, and fine cellular structures with cell size of similar to 0.45 mu m are obtained when performing a high scanning speed of 1200 mm/s. Notably, the correlation between the mechanical properties and the solidification cell size also indicates that the UTS and yield strength can be highly improved with the refinement of the alpha-Al cells, while the elongation to failure remains highly sensitive to the microstructural defects.

Graphene exhibits promise in gas detection applications despite its limited selectivity. Functionalization with fluorine atoms offers a potential solution to enhance selectivity, particularly towards ammonia (NH+) molecules. This article presents a study on electron-beam fluorinated graphene (FG) and its integration into gas sensor platforms. We begin by characterizing the thermal stability of fluorographene, demonstrating its resilience up to 450 °C. Subsequently, we investigate the nature of NH₃ interaction with FG, exploring distinct adsorption energies to address preferential adsorption concerns. Notably, we introduce an innovative approach utilizing x-ray photoelectron spectroscopy cartography for simultaneous analysis of fluorinated and pristine graphene, offering enhanced insights into their properties and interactions. This study contributes to advancing the understanding and application of FG in gas sensing technologies.

SiC-reinforced Al composites fabricated by additive manufacturing (AM) demonstrate great potential for engineering applications in aerospace, optics, automobile, and electronic packaging, owing to their lightweight nature, high specific strength, and exceptional corrosion resistance. In this work, microstructure evolution, thermal behavior and wear characteristics of SiC-reinforced AlSi10Mg composites fabricated via laser powder bed fusion (LPBF) were comprehensively investigated. The density measurements indicate that increasing the SiC content gradually decreases the relative density of LPBF-built SiC/AlSi10Mg composites, whereas higher laser power further decreases the relative density and therefore the densification level. Microstructural analysis reveals the formation of fish-scale molten pools with broadened boundaries in samples with high SiC content, and the eutectic Si network exhibits disrupted continuity, accompanied by dispersed precipitates formed via in-situ reactions between aluminum and SiC particles. These precipitated phases improve the microhardness up to 172 HV0.1 for samples with 10 % SiC and wear resistance up to 67 % reduction in wear rate versus pure AlSi10Mg. The variation in thermal conductivity is governed by competing mechanisms: densification level and residual precipitates. Furthermore, increasing the energy input during LPBF enhances the thermal conductivity, demonstrating that the influence of precipitate-dominated thermal behavior can outweigh the effects of reduced densification.

Electrochemical water oxidation reaction (WOR) lies among the most forthcoming approaches toward eco-conscious manufacturing of green hydrogen owing to its environmental favors and high energy density values. Its vast commoditization is restricted by high-efficiency and inexpensive catalysts that are extensively under constant research. Herein, calcium, magnesium, and yttrium doped lithium nickel phosphate olivines (LiNi1-xMxPO, LNMP; x = 0.1-0.9; M = Ca2+, Mg2+, and Y3+) were synthesized via non-aqueous sol-gel method and explored for catalytic WOR. Lithium nickel phosphates (LNP) and compositions were characterized via Fourier transform infrared, scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray diffraction techniques for the structural and morphological analyses. Glassy carbon electrode altered with the LNMPs when studied in a standard redox system of 5 mM KMnO4, displayed that yttrium doped LNP, i.e. LNYP-3 exhibits the highest active surface area (0.0050 cm(2)) displaying the lowest average crystallite size (D-avg) i.e. similar to 7 nm. Electrocatalytic behavior monitored in KOH showed that LNMP-2 offers the highest rate constant "k(o)," value, i.e. 3.9 10(-2) cm s(-1) and the largest diffusion coefficient "D-o," i.e. 5.2 x 10(-5) cm(2) s(-1). Kinetic and thermodynamic parameters demonstrated the facilitated electron transfer and electrocatalytic properties of proposed nanomaterials. Water oxidation peak current density values were indicative of the robust catalysis and facilitated water oxidation process besides lowering the Faradic onset potential signifying the transformation of less LNP into more conducive LNMP toward water oxidation.

The topological characteristics of the down-skin surfaces for as-built components by laser powder bed fusion (LPBF) are particularly representative, while the study on the improvement of the surface quality of these surfaces remains largely unexplored. Herein, the laser polishing of LPBF-built components with different inclination angles was systematically investigated with an emphasis on the down-skin surfaces. Our result shows that the topography of the top surface is independent of the inclination angle, and the surface topography of the down-skin surface is dominated by additional angle-dependent surface characteristics. It also indicates that the surface roughness can be reduced sharply when increasing the laser power from 40 W to 60 W, and the reduction slows down when further increasing the laser power while decreasing the scanning speed leads to a progressive improvement of the surface morphology. Moreover, a second-order regression model was established to evaluate the influence of the initial surface morphology and polishing parameters on the polished surface roughness and to achieve surface roughness optimization. Therefore, our established methodology can be readily applied to surface morphology manipulation and process optimization for laser polishing of widely used metals and alloys fabricated by the additive manufacturing process.

Two-dimensional (2D) materials such as MXenes have attracted considerable attention owing to their enormous potential for structural flexibility. Here, we prepared a Mo₂TiC₂T_x-layered structure from parent Mo₂TiAlC₂T_x MAX by chemically selective etching of the aluminum layer. The prepared MXene was employed in composite formation with CTAB-grafted multiwalled carbon nanotubes (MWCNTs) to have a structure with improved electrochemical performance. The samples were characterized to analyze the structure, morphology, elemental detection, vibrational modes, and surface chemistry, followed by an electrochemical performance of the Mo₂TiC₂T_x MXene and MWCNTs@Mo₂TiC₂T_x composite using the GAMRAY Potentiostat under a 1 M KOH electrolyte. The specific capacitance of pristine Mo₂TiC₂T_x was 425 F g^–1, which was enhanced to 1740 F g^–1 (almost 4 times) at 5 mV s^–1 due to the increase in active surface area and conductive paths between the MXene sheets. The charge storage mechanism was studied by further resolving the cyclic voltammograms. MWCNTs@Mo₂TiC₂T_x showed much improved electrochemical performance and reaction kinetics, making it an ideal material candidate for supercapacitor applications.

In this work, ammonia electrooxidation (AEO) is studied to probe the electrochemical behavior of aqueous NH₃ as direct fuel by implication of gamma alumina supported copper oxide catalysts (CuO/Al₂O₃). Precipitation and impregnation techniques are adapted to synthesize the substrate Al₂O₃, and loading of different ratios (1%, 2%, 3%, 4%) of active precursor i.e., CuO, respectively. Small average crystallite sizes (D_Avg) in range of 1.46–6.76 nm and smaller particle sizes from micrographs proposed a superb activity of the catalysts. Modified GCE exhibited the excellent conductive properties towards standard redox probe K₄[Fe(CN)₆] and KCl, displaying a high active electrochemical surface area of up to 0.0021 cm². Current profiles in response to increase in scan rates, concentrations of ammonia and temperature have been observed in 0.1 M KOH, thereby estimating the thermodynamic and kinetic constraints of the AEO process. Attributed to the electroactive properties towards AEO, CuO/Al₂O₃ is found to exhibit the desirable physiochemical properties owing to large oxidation current, large diffusion coefficient “D°” (3.6 × 10^-9 cm² s^-1), large rate constant “k^o” (1.2 × 10^-5 cm s^-1), large system entropy “ΔS” (-108 J K^-1 mol^-1), high change in enthalpy “ΔH” (72.3 J mol^-1) and low activation energy “ΔG” (32.8 kJ mol^-1). Resultingly, the oxidation of ammonia is found to be facile and robust by incorporation of CuO/Al₂O₃ catalysts owing to large k^o, ΔH and ΔH. This study opened a gateway towards eco-benign and economical efficient energy generation and viable market entry of direct ammonia fuel cells.

Direct hydrazine fuel cells (DHFC) insist on the evolved and persistent electrocatalysts for anodic hydrazine oxidation reaction (HzOR). Herein, PdO promoted CuO heterostructures supported on γ-Al₂O₃ are depicted as efficient electrocatalysts for HzOR. γ-Al₂O₃ is prepared by precipitation method while metal precursors are incorporated by co-impregnation technique. Physiochemically characterized PdO-CuO/Al₂O₃ mesoporous composites displayed large electrochemical active surface area (ECSA) i. e., 0.18 cm², high current density (j) i. e., 35.7 mA cm⁻², larger diffusion coefficient (D°) i. e., 29.3×10⁻⁴ (cm²s⁻¹), large apparent rate constant (k_app) i. e., 13.2 cm⁻¹ with low charge transfer resistance (R_ct) i. e., 3.6 kΩ shown by the best catalyst i. e., 1 % PdO-CuO/Al₂O₃. Cyclic voltammetry indicated that the fabricated working electrodes offer high efficiency towards HzOR in alkaline medium in such a way that 1 % PdO-CuO/Al₂O₃ produced 600 times higher oxidation current than CuO/Al₂O₃ composite. Owing to stability and reproducibility, PdO modified CuO/Al₂O₃ would achieve a huge catalytic significance in multiple electrochemical oxidation reactions with economic and ecological benefits.

Harnessing the power of sustainable hydrogen energy requires the development of efficient, non-precious metal electrocatalysts for water splitting. 2D materials, particularly MXenes offer potential solutions, given their unique attributes like metal-like conductivity, hydrophilic surfaces, and rich chemistry. In this research, we synthesized NiO@V2CTx, a novel bifunctional electrocatalyst with a synergistic three-layer structure. This composite merge the tunable properties of V2CTx MXene with the catalytic capability of NiO nanoparticles. By varying the NiO concentrations, we synthesized four distinct composites, each showing unique electrochemical characteristics. The 7.5 % composite (VN3), in particular, exhibited superior electrochemical performance with overpotentials of 253 mV (HER) and 346 mV (OER), along with Tafel slopes of 104 mV/dec and 91 mV/dec, respectively, to reach a benchmark current density of 10 mAcm  2. However, higher concentrations lead to blockage of active sites that diminish performance. The low charge transfer resistance (11.33 omega) of the Niadsorbed V2CTx MXene contributes to the rapid reaction kinetics and enhanced performance. The composite displayed exceptional durability, indicating its potential for long-term application. It maintained a high current retention of 93 %, indicating outstanding electrochemical stability. Moreover, the cell configuration using NiO@V2CTx//NiO@V2CTx requires a cell voltage of 1.75 V for overall water splitting. In essence, the VN3 composition was found to be the "sweet spot" for achieving optimal electrochemical performance, potentially offering benefits like high catalytic activity, enhanced conductivity, and improved durability.

Two-dimensional (2D) materials have sparked intense interest among the scientific community owing to their extraordinary mechanical, optical, electronic, and thermal properties. In particular, the outstanding electronic and optical properties of 2D materials make them show great application potential in high-performance photodetectors (PDs), which can be applied in many fields such as high-frequency communication, novel biomedical imaging, national security, and so on. Here, the recent research progress of PDs based on 2D materials including graphene, transition metal carbides, transition-metal dichalcogenides, black phosphorus, and hexagonal boron nitride is comprehensively and systematically reviewed. First, the primary detection mechanism of 2D material-based PDs is introduced. Second, the structure and optical properties of 2D materials, as well as their applications in PDs, are heavily discussed. Finally, the opportunities and challenges of 2D material-based PDs are summarized and prospected. This review will provide a reference for the further application of 2D crystal-based PDs.