Mesoporous chromium aluminophosphate （CrAIPO） was successfully synthesized via solid state reaction （SSR） route at low temperature in the presence of a cationic surfactant cetyltrimethyl ammonium bromide （CTAB） ...Mesoporous chromium aluminophosphate （CrAIPO） was successfully synthesized via solid state reaction （SSR） route at low temperature in the presence of a cationic surfactant cetyltrimethyl ammonium bromide （CTAB） and inorganic sources such as A1C13 · 6H20, CrCI3 · 6H20 and NaH2PO4 · 2H20. Characterizations by means of powder X-ray diffraction （XRD）, N2 adsorption- desorption, high resolution transmission electron microscopy （HR-TEM）, scanning electron micrography （SEM）, energy dispersion spectroscopy （EDS）, thermo-gravimetry （TG）, Fourier transform infrared spectroscopy （FT-IR）, and ultraviolet visible light spectroscopy （UV-Vis） were carried out to understand both the pore characteristics and electron transition route of these obtained materials. The experimental results show that the meso-CrA1PO materials with various Cr/A1 molar ratios possess a mesostructure and a specific surface area of 193 to 310 m2/g corresponding to an average pore size of 5.5 to 2.2 rim, respectively. The maxium content of Cr in meso-CrA1PO materials synthesized via SSR route can achieve 16.7wt%, being significantly higher than that of the meso-CrA1PO prepared via a conventional sol-gel route. Meanwhile, the formation mechanism of the meso-CrA1PO was also proposed.展开更多
According to the theory of crystal field, the existing state of chromium ions in β-C_2S was studied with optical spectra and EPR. The energy levels of chromium ions were calculated. Chromium ions exist in form of Cr^...According to the theory of crystal field, the existing state of chromium ions in β-C_2S was studied with optical spectra and EPR. The energy levels of chromium ions were calculated. Chromium ions exist in form of Cr^(4+) and Cr^(5+) coordinated with distorted octahedra. The reason of fading of β-C_2S hydrate is that the strength of light absorption declines be- cause of the valence change of chromium ions and chroninm dissolves out and loses in water.展开更多
基金Funded by the Program for New Century Excellent Talents in Universitythe Ministry of Education of China+3 种基金the National Natural Science Foundation of China (No.21061006)the Research of Natural Science and Technology Foundation of Guizhou Province ([2010]2006),Chinathe Natural Science Research Foundation of Education Bureau of Guizhou Province (No.2007083)the China Guizhou Province Characteristic Leading Academic Discipline Project in Material Physics and Chemistry (No.[2011]208)
文摘Mesoporous chromium aluminophosphate （CrAIPO） was successfully synthesized via solid state reaction （SSR） route at low temperature in the presence of a cationic surfactant cetyltrimethyl ammonium bromide （CTAB） and inorganic sources such as A1C13 · 6H20, CrCI3 · 6H20 and NaH2PO4 · 2H20. Characterizations by means of powder X-ray diffraction （XRD）, N2 adsorption- desorption, high resolution transmission electron microscopy （HR-TEM）, scanning electron micrography （SEM）, energy dispersion spectroscopy （EDS）, thermo-gravimetry （TG）, Fourier transform infrared spectroscopy （FT-IR）, and ultraviolet visible light spectroscopy （UV-Vis） were carried out to understand both the pore characteristics and electron transition route of these obtained materials. The experimental results show that the meso-CrA1PO materials with various Cr/A1 molar ratios possess a mesostructure and a specific surface area of 193 to 310 m2/g corresponding to an average pore size of 5.5 to 2.2 rim, respectively. The maxium content of Cr in meso-CrA1PO materials synthesized via SSR route can achieve 16.7wt%, being significantly higher than that of the meso-CrA1PO prepared via a conventional sol-gel route. Meanwhile, the formation mechanism of the meso-CrA1PO was also proposed.
文摘According to the theory of crystal field, the existing state of chromium ions in β-C_2S was studied with optical spectra and EPR. The energy levels of chromium ions were calculated. Chromium ions exist in form of Cr^(4+) and Cr^(5+) coordinated with distorted octahedra. The reason of fading of β-C_2S hydrate is that the strength of light absorption declines be- cause of the valence change of chromium ions and chroninm dissolves out and loses in water.
