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The reactions of dimethylzinc (DMZ) and diethylzinc (DEZ) on the As-rich c(4×4) reconstruction of GaAs(100) were studied using temperature programed desorption. Both DMZ and DEZ dissociatively adsorbed on the c(4×4) surface to form adsorbed Zn atoms and alkyl groups. The primary reaction pathway for surface methyl groups formed via dissociative adsorption of DMZ was desorption as methyl radicals between 500 and 720 K. A small fraction of the methyl groups also underwent dehydrogenation to form adsorbed hydrogen atoms and deposit carbon on the surface. In contrast, for surface ethyl groups formed from DEZ, the primary reaction pathway was β-hydride elimination to produce ethylene. Comparison of the results obtained in this study with those reported previously for the Ga-rich (4×2) reconstruction of GaAs(100) indicates that surface Ga atoms enhance the dehydrogenation activity of GaAs(100) surfaces.

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In this research, magnetic porous carbon was directly synthesized through one-step pyrolysis of FeCl3 – lotus seedpod mixture. Properties of the obtained material were analysed by X-ray powder diffraction, SEM image, nitrogen adsorption isotherm and vibrating sample magnetometer. The results showed that magnetic Fe3O4 particles were successfully formed over material template in 1 hour. The magnetic porous carbon possessed the specific magnetization of 7.13 emu/g, high specific surface area of 288 m2/g and total pore volume of 0.18 cm3/g. The material was subsequently applied as a potential catalyst for Ponceau 4R degradation by H2O2. Parameters including pH, H2O2 concentration, and different types of catalysts were investigated. At pH 3, 200 ppm H2O2, and 0.40 g/L magnetic porous carbon, 83% Ponceau 4R 50 ppm was removed after 120 minutes treatment. Moreover, the catalyst powders were separated from the treated mixture easily by a magnet. Summarily, magnetic porous carbon can promise to be an efficient catalyst in decomposition of Ponceau 4R.