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Recycling silicon from environmentally hazardous diamond wire saw silicon powder waste (DWSSP) and effectively removing boron is still an elusive aim. Here, pressure-less sintering and dynamic-slag...

Titanium (Ti) and calcium (Ca), as trappers, were introduced into copper-alloyed metallurgical grade silicon (MG-Si). The effects of trappers on the segregation behavior and removal efficiency of phosphorus (P) were investigated. It was found that P tended to enrich in the TiSi2 and CaCu2Si2 phases, and quenching above the eutectic temperature of Si-Cu alloy is conducive to the P removal. The corrosion process of the P-enriched phases indicated that Ca addition was in favour of P removal, while Ti addition was opposite. The results suggested that though the addition of Ti and Ca could effectively enrich P in the Si-Cu alloy, the acid sensitivity of P-enriched phases would affect the P removal.

The electrochemical performance of lithium iron silicate (Li2FeSiO4) as a cathode material for lithium ion batteries would be remarkably enhanced by selective substitution of 25% oxygen with 25% sulfur to form a Li2FeSiO3S compound based on the previous first-principles calculation. However, the experimental verification has little studied. In this work, the sol-gel precursor and solid-state reaction route was employed to prepare a series of carbon coated Li2FeSiO4 (Li2FeSiO4/C) composites with different sulfur modifications using 1-dodecanethiol as a sulfur source material. The effects of important preparation parameters including sucrose amount, sulfur content, sintering temperature and sintering time on the crystal structure, surface morphology and electrochemical performance of sulfur modified Li2FeSiO4/C composites were investigated through orthogonal design experiments. The results indicated that the significance of the influence on the capacity performance in decreasing order followed sulfur doping content > carbon content > sintering temperature > sintering time. The optimized synthesis conditions were determined to be carbon content of 50% and sulfur doping content of 20% with the sintering temperature at 650°C for 12 h.

The carbon supported PdCu alloyed catalysts (PdCu/C) with different molar ratios of Cu to Pd (Cu/Pd), namely, Cu/Pd=2.0, 3.0, 4.0, and 5.0, were synthesized by a simple and facile two-step method. The Cu nanoparticles were first obtained by microwave assisted method, and then followed by galvanic substitution of Pd on Cu nanoparticles. The PdCu/C catalysts exhibited mainly cubic phase with the average crystallite sizes ranging 4.0~4.5 nm by varying the Cu/Pd ratios of 2.0~5.0. The microstructure and the activity toward oxygen reduction reaction (ORR) of PdCu/C were significantly influenced by the Cu/Pd ratios. The higher degree of alloying and better ORR activity could be achieved with the Cu/Pd=4.0. The half-wave potential (E1/2) reached 0.760 V in the acid medium, which was only 40 mV lower than that of commercial Pt/C. Only 20 mV (2.6%) decrease in E1/2 after 1000 cycles between 0.4 and 1.0 V suggested the good stability.

In this study, titanium was introduced to a Cu-Si alloy as an impurity getter to redistribute boron. A small amount of Ti was melted with Cu-Si alloy, followed by cooling of the alloy to precipitate purified Si crystals which were later separated through multi-step leaching. The effects of Ti content on the distribution of various elements in different phases and microstructure of the solidified alloy were investigated. It was found that Ti in Cu-Si alloy facilitates boron removal by several mechanisms including formation of TiB2 and decreasing the segregation coefficient of B between Si and Cu-Si. Addition of Ti to a Cu-50 wt%Si alloy, compared to silicon metal, showed a significant increase in B removal. An increase in Ti in the range of 1–5% increased B removal, reaching ∼85% at 5% Ti addition. Ti in excess of that required to form TiB2 reacts with Si to generate TiSi2, which collects impurities such as P and Al.

Large-scale cupric oxide (CuO) nanowires have been synthesized by thermal evaporating copper foils in O2 ambient at the temperatures from 300°C to 900°C. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were performed on the study of the CuO nanowires. XRD studies reveal the possibility of two-steps of nanowire formation; HRTEM image shows the bicrystal structure of the nanowire; SEM studies indicate the relationship between the morphology of the prepared nanowires and the growth conditions. The growth of the nanowires seems to be vapor–solid (VS) mechanism.

Hafnium-based dielectrics have been extensively investigated as a possible replacement for SiO 2 . Anhydrous Hf/Zr mixed-metal nitrate precursor Hf x Zr 1−x (NO 3 4 (HZN) was successfully synthesized and hafnium zirconate (Hf x Zr 1− O 2 ) thin films were prepared by the chemical vapor deposition (CVD) technique from this precursor. The basal dielectric properties of Hf x Zr 1− O 2 films were studied, and C-V curves with negligible hysteresis are achieved.