Synthesis of mesoporous chromium phosphatesvia solid-state reaction at low temperature

Abstract

Using solid-state reaction at low temperature (SSRLT), mesoporous chromium phosphates were successfully synthesized in the presence of a surfactant template, cetyltrimethyl ammonium bromide (CTAB), at a temperature of 353 K without using a water solvent. The synthesized chromium phosphates were characterized by XRD, EDS, HR-TEM, N₂-physisorption, TGA-DSC, FT-IR, and UV-vis spectroscopies. It was found that mesoporous chromium phosphate can be formed only at atomic ratios of P/Cr ≥ 1.8. The mesophase at P/Cr = 2.0 showed the highest ordering of pore arrays, with a specific surface area as high as 250.78 m² g^-1 and an average pore size of 3.48 nm. The catalytic performance of the synthesized chromium phosphates was examined using the dehydration of isopropanol to propene as the model reaction. The results indicated that the mesoporous chromium phosphates synthesized via the SSRLT route exhibited significantly higher isopropanol conversions and propene yields than that synthesized via the solution sol–gel route and the non-mesoporous chromium phosphate.