High-energy Ball Milling Method Research Articles

A ball milling method for highly dispersed Ni atoms on g-C3N4 to boost CO2 photoreduction

Atomically dispersed active sites can effectively enhance the catalytic activity, but the synthesis of highly dispersed single-atom active sites remains challenging. Herein, we report for the fabrication of single-atom Ni on g-C3N4 (CN) catalysts for photocatalytic CO2 reduction reaction (CO2RR) using a high-energy ball milling method. The uniformly loaded single-atomic Ni on the surface of the substrate suggests the improvement of synthetic methods. After optimizing the Ni loading, the photocatalyst containing 0.5 at% (0.32 wt%) single-atomic Ni (Ni/CN-0.5) exhibited the highest CO2 reduction performance (∼19.9 μmol·g−1·h−1) without any co-catalyst or sacrificial agent. As visualized by aberration-corrected high-angle annular darkfield scanning transmission electron microscopy (AC HAADF-STEM), the Ni atoms in the Ni/CN-0.5 photocatalyst are most uniformly dispersed for different loadings (0.1, 0.3, 0.5, 0.7, 1.0, 3.0 and 5.0 at%). These results suggest that the uniformity of the single-atom active sites plays a decisive role rather than the loading amount in the highly enhanced performance. This work provides insight into the design of photocatalysts with highly dispersed single-atom catalytic active sites for enhancing activity.

High energy ball-milled nano-Ti polymer: Kinetic analysis and synergetic effect

The Nano-Ti polymer was successfully fabricated by a high-energy ball milling method based on the principle of mechanochemistry. The influence of key parameters of ball-to-material ratio, ball-to-diameter ratio, and grinding solvent on the microstructure and dispersion capability of Nano-Ti polymer was investigated to attain an optimal preparation formula. Results show that the prepared Nano-Ti polymer has good dispersion stability. With increasing the ball-to-material ratio, the particle size and the sedimentation rate of Ti powder decrease. With decreasing the weight of the Φ20 mm grinding ball and increasing the weight of the Φ15 mm grinding ball, the sedimentation rate of the Nano-Ti polymer first increases and then decreases. The addition of grinding solvent is beneficial to improving the dispersion stability of Nano-Ti polymers. When the total ball weight is 2600 g and the weight ratio for the three types of balls is 16:7:3 (Φ20 mm: Φ15 mm: Φ5 mm), and the grinding aid is epoxy resin solvent containing acetone, the prepared Nano-Ti polymer has the best dispersion stability, the smallest sedimentation rate (6%) and particle size (28.1 nm), and the largest grafted amount (5.59 ×1019/m2) with epoxy resin.

Enhanced Antioxidant Effects of Naringenin Nanoparticles Synthesized using the High-Energy Ball Milling Method.

Naringenin, one of the flavonoid components, is majorly found in and obtained from grapefruits and oranges. Naringenin also acts as a potent antioxidant, which possesses hypolipidemic as well as anti-inflammatory potential. Naringenin reduces the expressions of several inflammatory mediators, viz., NF-κB, cycloxygenase-2, and other cytokine mediators. In spite of having various biological effects, the clinical application of naringenin is restricted due to its very poor aqueous solubility. In the present study, the high-energy ball milling method was employed for the preparation of naringenin nanoparticles without using any chemical with an aim to enhance the anti-oxidant potential of naringenin. The milled naringenin nanoparticles were characterized for their physicochemical properties using scanning electron microscopy (SEM) and X-ray diffraction. Additionally, the effects of milling time and temperature were further assessed on the solubility of crude and milled naringenin samples. The antioxidant potential of milled naringenin was evaluated with various assays such as DHE, DCFDA, and cleaved caspase-3 using SH-SY5Y human neuroblastoma cells. The nanoparticle size of naringenin after milling was confirmed using SEM analysis. Crystalline peaks for milled and crude samples of naringenin also established that both the naringenin forms were in the crystalline form. The solubility of naringenin was enhanced depending on the milling time and temperature. Moreover, crude and milled naringenin were found to be cytocompatible up to doses of 120 μM each for the duration of 24 and 48 h. It was also observed that milled naringenin at the doses of 1, 2, and 5 μM significantly reduced the levels of reactive oxygen species (ROS) generated by H2O2 and exhibited superior ROS scavenging effects as compared to those of crude or un-milled forms of naringenin. Furthermore, milled naringenin at the doses of 1 and 2 μM inhibited H2O2-induced cell death, as shown by immunofluorescence staining of cleaved caspase-3 and Annexin-V PI flow cytometry analysis. Conclusively, it could be suggested that the size reduction of naringenin using high-energy ball milling techniques substantially enhanced the antioxidant potential as compared to naïve or crude naringenin, which may be attributed to its enhanced solubility due to reduced size.

Leakage Rate Control of Magnetic Powder Seals by Lubricant Coatings on Magnetic Nanoparticles and Flow Field Simulation

Magnetic fluid seals (MFSs) have been a popular sealing method, with unique advantages compared to traditional mechanical seals, such as zero leakage, long lifetime, and low resistance torque. However, restricted by the properties of carrier fluids, MFSs cannot work under extremely high or low temperatures. To ensure stability, the pressure capability per stage is also limited. Recently, a novel sealing method using nano-micro magnetic powders has been presented to solve the problems, and leakage rates turn out to be a main focus. Here, we realize the leakage rate control by lubricant coatings on magnetic nanoparticles. Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> nanoparticles coated with solid lubricants are prepared by the high-energy ball milling method. Effects of different types of lubricants and ball milling parameters on the leakage rate are studied by magnetic powder sealing experiments. Permeability of magnetic powders is estimated from the experimental data. Furthermore, the flow field distribution of a real magnetic powder seal (MPS) is simulated.

Refining of copper powder by a novel micro-abrasive milling method conducted in the air

• Copper powder was refined by conventional milling and micro-abrasive milling. • Finer powder was prepared under the co-effect of micro-abrasives and oxygen. • The milled powder was converted into Cu 2+1 O with an average size of 375.4 nm. • The average size of the dispersed powder was reduced to 179.5 nm. • During the dispersion process, Cu 2+1 O was partly converted into CuO. The pure copper powder was milled by conventional high-energy ball milling (CM) and micro-abrasive milling (MAM) methods in the air or vacuum. The refining behavior of copper powder milled using these different methods has been studied, and the morphologies, microstructures, compositions, and properties of the milled powders have been thoroughly investigated. The results show that, as compared to CM, the MAMed copper powder had a better refinement behavior and contained a smaller number of agglomerates. After milling in the air for 30 h by MAM, whole copper powder was converted into Cu 2+1 O. In addition, under the synergistic effects of micro-abrasion and exposure to oxygen, the Cu 2+1 O powder was soft-agglomerated and had a specific surface area of 15.1031 m 2 /g and an average size of 375.4 nm. During the dispersion process, Cu 2+1 O was partly converted into CuO and the microstructural evolution characteristics were disclosed. The dispersed powder had an average particle size of 179.5 nm. The refining mechanism of the copper powder prepared by the micro-abrasive milling method was also discussed.

Evolution of Microstructure and Mechanical Properties of CNTs/Al-Mg Composites Prepared by Powder Metallurgy

In this research, 1 wt% carbon nanotubes/aluminum 5 wt% Mg (CNTs/Al-Mg) composites were fabricated using powder metallurgy and hot pressing method. Dislocation density increases and dislocation cell structure is formed in Al-Mg particles for the repeared flattening, cold welding, fracturing and rewelding during ball milling. The horizontal stirring high-energy ball milling method can uniformly disperse 1 wt% CNTs in Al-Mg matrix powders, and can form an effective composite interface bonding. Some parts of the carbon nanotubes are twisted to form carbon nanoonions. After 90 min of ball milling, the tensile strength of the composite material obtained by hot pressing reached the maximum value, which was 244 MPa, which was increased by 31% compared with the composite materials none milled.

Synergistic Effect of a Facilely Synthesized MnV2O6 Catalyst on Improving the Low-Temperature Kinetic Properties of MgH2.

While magnesium hydride (MgH2) has drawn considerable attention as a promising hydrogen storage material, it suffers from sluggish kinetics and high desorption temperature, hindering potential applications. Herein, we show that the hydrogen desorption kinetics of MgH2 can be significantly improved using bimetallic oxide MnV2O6 as the catalyst. A MgH2-MnV2O6 composite was prepared by a high-energy ball milling method. The results showed that the MgH2-MnV2O6 composite can release 5.57 wt % hydrogen within 10 min under 250 °C. The dehydrogenated MgH2-MnV2O6 sample can absorb 3.09 wt % hydrogen within 10 min under 50 °C. Notably, the reversible hydrogen storage property did not degrade at least within 100 cycles, showing excellent cycle stability. X-ray diffraction and transmittance electron microscopy measurements revealed that MnV alloy and V2O3 phases were formed during the ball milling process, leading to the synergistic catalytic effect. We argue that the bimetallic MnV alloy plays key catalytic roles in this system because MnV alloy can promote the fracture of the H-H and Mg-H bonds, significantly improving the hydrogen storage kinetics and low-temperature reversible hydrogen storage performance of MgH2.

Magnetic phase diagram of BHF-NZFO composite at room temperature

Composites of barium hexaferrite (BaFe12O19) and nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) have been prepared by the high-energy planetary ball mill method. The magnetic composites are characterized by employing X-ray Diffraction and High-Resolution Transmission Electron Microscopy (HRTEM) techniques. The percentage of barium hexaferrite (BaFe12O19) and nickel zinc ferrite (Ni0.5Zn0.5Fe2O4) in the composite has been obtained from the Rietveld analysis of XRD patterns. The average crystallite sizes of BHF and NZFO are found to be comparable in the composites. The magnetic properties of (1-x) BHF-(x) NZFO with x = 0 to 1 have been studied by measuring the magnetic hysteresis loop (M-H loop) for all the samples. The M-H loops are analyzed by plotting the loop width (ΔH) versus magnetization (M). The magnetic hysteresis loops for the BHF and NZFO are found to be symmetric in all the quadrants. However, symmetry breaks in M-H loops for composites. The symmetry breaking in magnetic hysteresis loops of the bi-magnetic composite suggests a new approach to analyzing the magnetic interaction between magnetic phases in the magnetic composites.

Laser-Induced Exothermic Bonding of SiCp/Al Composites with Nanostructured Al/Ni Energetic Interlayer

In this study, SiCp/Al composites were bonded using the laser-induced exothermic bonding method. The nanostructured Al/Ni energetic materials were prepared by the high-energy ball-milling method and served as the bonding interlayer. The joint microstructure was characterized by SEM, EDS, TEM, and XRD. The effect of Zr content on the joint microstructure and shear strength was investigated. The results indicated that after the ball-milling process the Al and Ni particles underwent strong plastic deformations and were welded to each other, forming the nanostructured Al/Ni energetic materials with a lamellar structure. Compared with the raw powders, the location of the exothermic peak decreased by 42 K, and its exothermic performance was significantly improved. The exothermic reactions that occurred in the Al/Ni interlayer provided the required heat for the bonding process. Near the bonding interface, the interlayer could not react completely due to the cooling effect of the substrates, forming a mixture of residual metal particles and Ni-Al compounds. The addition of Zr content enhanced the interfacial reactions between the bonding interlayer and the SiCp/Al composites. The interlayer products transformed from NiAl to the eutectic organization of NiAl + Ni-Al-Zr, thus decreasing the pores in the joint and improving the bonding quality. With an increase in the Zr content, the joint shear strength first increased and then decreased. When the Zr content was 10 wt.%, the joint shear strength reached a maximum of 22 MPa.

Nanostructured Al/Ni energetic composites: processing, reaction properties and activation energy

In this study, the nanostructured Al/Ni energetic composites were processed using the high-energy ball milling method. The milling conditions, i.e. the ball to powder ratio (BPR), ball sizes, and milling time, were varied to investigate their effect on the microstructures and reaction properties of the Al/Ni NECs. Results indicated that large BPR, appropriate size assortment of milling balls, and long milling time promoted the formation of nano lamellar structure and improved the reaction performance. When the BPR was 10 and the milling time was 100min, the Al/Ni NECs had a nano lamellar structure and a low ignition temperature of 619 K. The activation energy was calculated to be 54.49 kJ/mol using the Kissinger method, and 63.87 kJ/mol using the Ozawa method, respectively.

Research on Preparation and Mechanical Properties of Multilayer Graphene Reinforced Aluminum Matrix Composite

In order to solve the problem of the dispersion of graphene in aluminum-based composite materials, a high-energy ball milling method was used to prepare graphene/aluminum-based composite powder, and then the graphene/aluminum composite material was obtained by vacuum hot pressing. XRD, SEM, TEM were used to analyze and study the morphology and microstructure of graphene/aluminum-based composite powders, and the tensile mechanical properties, hardness and fracture morphology characteristics of graphene/aluminum-based composites. The research results show that the addition of graphene can reduce the cold welding of aluminum powder during the high-energy ball milling process, and obtain better dispersed graphene/aluminum composite powder; when the content of graphene is 1 wt.%, the composite material The tensile strength can reach 295.62 MPa, the hardness is 113.6HV, which is 24% higher than the pure aluminum tensile strength, and the hardness is increased by 20%; graphene exists in the dimples of the tensile fracture, under the action of tensile force, Graphene can carry load transfer and improve the tensile strength of composite materials, which is the enhancement mechanism of graphene in aluminum-based composite materials.

Effect of High-Energy Ball Milling Mixing Process on Electrical Performance and Synthesis Temperature of LiFePO4/C Cathode Material

In this paper, high-energy ball milling method was used to prepare LiFePO4/C precursor and high temperature solid phase method to prepare LiFePO4/C cathode material. The influence of mixing process on the electrical performance and synthesis temperature of LiFePO4/C cathode material was studied by changing the ball milling time.The ball milling time selected in this paper is 0, 0.5, 1, 1.5, 2 h, and XRD, SEM and particle size analysis are used to characterize the properties of LiFePO4/C powder. The research results show that the LiFePO4/C powder obtained under the ball milling time of 1 h has the smallest particle size and uniform distribution. The XRD results also show that the LiFePO4/C phase obtained under this condition has good purity and crystallinity.The electrical performance of the LiFePO4/C material prepared after high-energy ball milling are tested. The results show that the first discharge specific capacity at 0.2 C rate is 163.3 m·Ah/g, which is 19.7% higher than that of the non-ball milled sample.The TG-DTA curve results show that the reaction temperature of the sample after high-energy ball milling is 454 °C, and the mass loss ends at about 570 °C. Compared with the sample without ball milling, the reaction temperature is reduced by 60 °C.The results of this study show that the preparation of precursor by high-energy ball milling can effectively improve the electrical performance of LiFePO4/C materials and reduce the material synthesis temperature.

Multifunctional interstitial-carbon-doped FeCoNiCu high entropy alloys with excellent electromagnetic-wave absorption performance

Electromagnetic-wave absorbing (EMA) materials that have efficient absorption performances, great mechanical properties and chemical stability are rare and yet essential for communication security and protection. Herein, flaky interstitial-carbon-doped FeCoNiCu high entropy alloys (HEAs) as novel EMA materials were successfully prepared by high-energy ball-milling method. Interstitial-carbon doping as a modulating approach impacted the phase forming, morphology and electromagnetic properties of FeCoNiCu HEAs. Impedance matching was significantly optimized via tuning interstitial carbon contents. The carbon-doped FeCoNiCu HEAs with appropriate carbon contents delivered superior EMA performance compared with other HEAs EMA materials. Strong reflection loss as low as -61.1 dB in the Ku band, broad effective absorption bandwidth of 5.1 GHz was achieved for FeCoNiCuC0.04. Moreover, the carbon-doped FeCoNiCu HEAs exhibited excellent mechanical hardness and chemical stability. This work not only suggests that interstitial-carbon doping is an available approach to tuning electromagnetic properties of HEAs, but also presents carbon-doped FeCoNiCu HEAs as promising EMA materials for civilian and military due to the efficient absorption, broad bandwidth, great durability and stability.

Influence of ammonium octamolybdate on flame retardancy and smoke suppression of PVC matrix flame retardant composites

Abstract In order to improve the flame retardancy and smoke suppression of polyvinyl chloride (PVC), ammonium octamolybdate (AOM)/nano-antimony trioxide (nano-Sb2O3)/dioctyl Phthalate (DOP)/PVC composites were prepared by high energy ball milling and melt blending methods using AOM as the smoke suppressant. The effects of AOM on the flame retardancy and smoke suppression of the PVC composites were studied by means of vertical burning tests (UL-94), limiting oxygen index (LOI), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and cone calorimetry (CCT). The results showed that the flame retardancy of PVC composites containing AOM was improved, namely the UL-94 grade of the composites reached the V-0 grade and the LOI increased from 22.3% to 30.6%, whilst the heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSR) and smoke factor (SF) decreased significantly. In addition, AOM could promote the dehydrochlorination reaction of the PVC composites at lower temperature, resulting in more compact and continuous char residues. Therefore, AOM is an effective smoke suppressant and has a good synergistic flame retardant effect with nano-Sb2O3 in flame retardant PVC matrix composites.

High-performance silicon from quartz product waste as an anode material for Li-ion batteries

As the demand for quartz products increases year over year, the increase in the production of quartz waste has gradually contributed to increases in resource waste and environmental pollution. To recover quartz from spent quartz product waste and realize its high-value utilization, quartz waste ($0.15/kg) was used as the raw material to prepare high-performance porous silicon as an anode material for lithium ion batteries via a simple high-energy ball-milling method, followed by magnesiothermic reduction. The formation mechanism of silicon from quartz particles with different particle sizes during magnesiothermic reduction was investigated by X-ray diffraction, field-emission scanning electron microscopy, and other methods. The preparation of porous silicon without residual impurities was determined to be highly dependent on the size of the quartz particles after high-energy ball milling. When formed into an anode material for electrochemical measurements, the pure porous silicon (Si-4) anode delivered an initial specific charge capacity of 2712 mAh·g−1 with a high initial Coulombic efficiency of 81% at a current density of 200 mA g−1. The specific capacity was sustained at 923 mAh·g−1 for 300 cycles at a current density of 4000 mA g−1. The results reported herein highlight the feasibility of recovering spent quartz resources for harmless treatment and high-value utilization.

Effect of bonding process on the microstructures and strength of W/steel joints with a W-Cu-Ni interlayer

Bonding between W and steel using a 90W-9Cu-1Ni powder mixtures/Ni multi-interlayer was carried out in vacuum for 60 min at 1120 °C with a bonding pressure of 20 MPa and a bonding pressure of 5 MPa assisted with presetting Co powder on the surface of W. The microstructures, composition distribution, and fracture characteristics of the joint were studied by SEM, EDS. Joint properties were evaluated by shear experiments tests. The results showed that the joints comprised W/W-Cu-Ni composites/Ni/steel. The W-Cu-Ni composites with a homogeneous and dense microstructure formed by liquid phase sintering of 90W-9Cu-1Ni powder mixtures prepared by high energy ball mill method. Under the bonding pressure of 20 MPa, a bonding line with a width of about 0.5 μm and high element tungsten content formed between W-Cu-Ni composites and W, which resulted in high shear strength (275 ± 12 MPa) of the W/steel joints and failure during testing was always located at W near the W-Cu-Ni composites/W interface. For the bonding process of bonding pressure of 5 MPa assisted with presetting Co powder on the surface of W，μ-(Co, Ni)7W6 intermetallic compounds layers were formed in W-Cu-Ni composites and W, which atomic ratio of Co to Ni is 2 to 1. The average shear strength of W/steel joints bonded by this bonding process was 242 ± 9 MPa and all joints were fractured in the Ni layer near the W-Cu-Ni composites/Ni interface.

Fabrication and Characterization of Submicron-Scale Bovine Hydroxyapatite: A Top-Down Approach for a Natural Biomaterial.

Submicron hydroxyapatite has been reported to have beneficial effects in bone tissue engineering. This study aimed to fabricate submicron-scale bovine hydroxyapatite (BHA) using the high-energy dry ball milling method. Bovine cortical bone was pretreated and calcined to produce BHA powder scaled in microns. BHA was used to fabricate submicron BHA with milling treatment for 3, 6, and 9 h and was characterized by using dynamic light scattering, scanning electron microscope connected with energy dispersive X-Ray spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffractometry to obtain its particle size, calcium-to-phosphorus (Ca/P) ratio, functional chemical group, and XRD peaks and crystallinity. Results showed that the particle size of BHA had a wide distribution range, with peaks from ~5 to ~10 µm. Milling treatment for 3, 6, and 9 h successfully gradually reduced the particle size of BHA to a submicron scale. The milled BHA’s hydrodynamic size was significantly smaller compared to unmilled BHA. Milling treatment reduced the crystallinity of BHA. However, the treatment did not affect other characteristics; unmilled and milled BHA was shaped hexagonally, had carbonate and phosphate substitution groups, and the Ca/P ratio ranged from 1.48 to 1.68. In conclusion, the fabrication of submicron-scale BHA was successfully conducted using a high-energy dry ball milling method. The milling treatment did not affect the natural characteristics of BHA. Thus, the submicron-scale BHA may be potentially useful as a biomaterial for bone grafts.

Enhanced Electromagnetic-Wave Absorbing Performances and Corrosion Resistance via Tuning Ti Contents in FeCoNiCuTix High-Entropy Alloys.

Efficient and stable electromagnetic-wave (EMW) absorption materials have attracted great attention in the field of reducing microwave pollution. Herein, FeCoNiCuTix high-entropy alloys (HEAs) as electromagnetic-wave absorbing materials were prepared by a high-energy ball-milling method. The as-milled HEA powders presented a flaky shape with a high aspect ratio. Impedance matching was efficiently optimized by severe lattice distortion, which was caused by Ti incorporation. The introduced plentiful defects in FeCoNiCuTix HEAs provided abundant polarization sites for dielectric loss. By tuning Ti contents, FeCoNiCuTi0.2 HEAs delivered excellent EMW absorption performances. The maximal reflection loss (RLmax) values reached -47.8 dB at 10.86 GHz as thin as 2.16 mm, and the widest bandwidth was 4.76 GHz (5.97-10.73 GHz). Furthermore, the introduction of Ti enhanced corrosion resistance via increasing the charge transfer resistance of a passivated film. Those characteristics of FeCoNiCuTix HEAs made these materials a practical gigahertz-range EMW absorber. Additionally, our findings provided a facile and tunable strategy for designing EMW absorbing materials, which was aimed at lightweight, highly efficient absorption, and resistance to harsh environments.

Magnetic and microwave absorbing properties of La0.7Sr0.3MnO3 nanoparticles

The magnetic and absorbing properties of La0.7Sr0.3MnO3 nanoparticles created by ceramic and high-energy ball milling methods were investigated in detail in this study. The x-ray diffraction data show that they belong to a rhombohedral structure with an average crystalline size of ⟨D⟩ = 41 ± 2 nm. The field emission scanning electron microscope image showed that the La0.7Sr0.3MnO3 particles have a pseudo-spherical shape with particle sizes ranging from 20 to 100 nm. The Curie temperature (TC), effective paramagnetic moment, coercivity (Hc), and saturation magnetization (Ms) of the sample were determined using the temperature and magnetic field dependences of the magnetization. It shows that La0.7Sr0.3MnO3 nanoparticles exhibit a soft ferromagnetism with TC = 358 K and Hc ≈ 15 Oe and Ms ≈ 60 emu/g at 300 K. The microwave reflection loss (RL) of La0.7Sr0.3MnO3–paraffin composites with thicknesses t = 1.5–3.5 mm at room temperature was measured at frequencies 4–18 GHz using a vector network analyzer. The largest negative RL values obtained for un-backed and Al-backed samples are about −14.07 dB at 17.97 GHz and −24.87 dB at 14.71 GHz corresponding to the absorbing thicknesses t = 1.5 and 2.0 mm, respectively. These resonant effects are explained by the impedance matching mechanism in the samples.

Study on preparation methodology of zero-valent iron decorated on graphene oxide for highly efficient sonocatalytic dye degradation

Various preparation methodologies (stirring, hydrothermal, and high energy ball milling methods) were used to prepare zero-valent iron (ZVI) catalysts decorated on graphene oxide (GO) for highly efficient sonochemical dye degradation, and their dye degradation efficiencies were compared. For the effective activation of ZVI, N,S co-doped GO (N,S-GO) prepared by high-energy ball milling synthesis was also tested. According to the preparation methodologies, the ZVI catalysts showed different degrees of surface passivation, morphologies, and zeta-potentials because of the different degrees of aerial oxidation of ZVI, which are the key factors determining their activities in sonocatalytic dye degradation. The ZVI catalysts on GO prepared using the stirring and hydrothermal methods showed a high oxidation state with low sonocatalytic activity. In contrast, the ZVI catalysts on GO prepared using the high-energy ball milling method exhibited moderate sonocatalytic activity due to moderate passivation. The ZVI on N,S-GO prepared by stepwise high-energy ball milling synthesis showed the maximum activity (100% removal efficiency within 1 min) due to the minimum aerial oxidation. The rapid generation of •OH radicals by high-energy sonication, the existence of mixed-valence states of iron via activation, and N,S-doping facilitated electron transfer for the dye degradation process. The complete mineralization and degradation pathway of crystal violet dye was confirmed by electrospray ionization-mass spectrometry.