Synthesis of mesoporous chromium phosphate through an unconventional sol–gel route

Mesoporous chromium (III) phosphate has been synthesized first time using an unconventional sol–gel technique using inexpensive chromium source ammonium dichromate. In situ synthesized chromium (III), prepared through reduction of ammonium dichromate using ethanol and nitric acid, forms gel in presence of ammonium dihydrogen phosphate and urea at elevated temperature where tetradecyltrimethylammonium bromide (TTBr) is used as structure directing agent. High specific surface area of 384 m2/g with narrow pore size distribution has been achieved after extracting the surfactants with ethanolic sodium acetate solution. EDS analysis shows that the Cr/P ratio is 1.05. The material was characterized by powder low angle X-ray diffraction (XRD), wide angle XRD, N2 adsorption–desorption, HRTEM, FTIR, UV–visible and ESR spectroscopy. Wide-angle XRD patterns show the amorphous nature of the compound. UV–visible and ESR spectroscopic data shows the presence of octahedrally coordinated Cr3+ solely.