直流电弧等离子体制备纳米SiC及其催化特性

利用工业块体硅为硅源, CH₄为碳源, 在含有H₂和Ar混合气氛中, 采用直流电弧等离子体法制备SiC纳米粒子。CH₄含量影响SiC纳米粒子的化学组成和形貌。结果显示: 产物中含有3C-SiC和6H-SiC两种物相, 而在CH₄压力为0.005 MPa条件下制备的SiC纳米粒子还含有Si/SiC核壳结构。利用制备的SiC纳米颗粒作为催化剂, 在恒光强下光电催化还原脱除2,4-二氯酚中的Cl原子。结果显示在-1.02 V偏压下光电催化180 min后, 对2,4-二氯酚的去除效率达92.5%, SiC纳米粒子的吸附效率为19.6%。因此, SiC纳米颗粒可取代贵金属, 作为低成本光电催化候选材料用于污水处理。

Synthesis and Catalytic Performances of SiC Nanoparticles by DC Arc-discharge Plasma

SiC nanoparticles were synthesized by direct current (DC) arc-discharge plasma method, using bulk Si as silicon source and in a mixed atmosphere of CH₄, H₂ and Ar. The chemical composition and morphology of the SiC nano product were affected by the pressure of CH₄ obviusly. These products were characterized by Transmission electron microscopy (TEM), Raman spectra, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicate that the product contains the main phases of 3C- and 6H-SiC, while prepared at low CH₄ pressure of 0.005 MPa, which exists few Si/SiC core-shell structures in the product. The SiC nanoparticles, prepared at 0.01 MPa CH₄, were used as the catalyst to remove the Cl atoms in persistent 2,4-dichlorophenol through photoelectric catalytic reduction. The results show that the SiC nanoparticles have good photoelectric catalytic reductive dechlorination ability under ultraviolet illumination at a constant optical intensity of 500 mW/cm². The removal efficiency reaches about 92.5% and the adsorption efficiency is 19.6% at an appropriate bias potential of -1.02 V after 180 min of photoelectric catalysis. Hence, SiC nanoparticles are identified as a kind of low-cost photoelectrocatalysis candidates to replace noble metals in wastewater treatments.