The Hydrothermal Synthesis And Characterization Of Porous Molybdenum Phosphates

Phosphates as a kind of inorganic microporous materials, have been widely used in catalysis, adsorption, separation and ion exchange because of their many types of framework elements, pore and cage structures. Molybdenum phosphates with microporous structure are a class of transition metal phosphates materials, and have novel open framework. Detailed conditions for synthesis of MoPO and application have not be reported, so the synthesis law of microporous molybdenum phosphates materials was researched systematically and different organic templates have been used trying to synthesize new molybdenum phosphates in this paper.MoPO-1, MoPO-2 and MoPO-3 were synthesized by hydrothermal synthesis method with tetramethylammonium hydroxide, triethylenediamine, diethylenetriamine, tetraethylenepentamine and piperazine as templates, and the typical samples were characterized by XRD, TG, CHN and SEM. The main contents and results are listed as follows:Firstly, MoPO-1(TMA) and MoPO-1(DABCO) were synthesized in the hydrothermal system with tetramethylammonium hydroxide and triethylenediamine as templates, respectively. The former optimal synthetic condition is MoO3: H3PO4: TMAOH: H2O=1.0: 3.5: 1.3: 97.0 (mol ratio, the same below), at 220℃for 3 days. The latter optimal synthetic condition is MoO3:H3PO4: DABCO: H2O=1.0: 3.3: 1.3: 83.3 at 220℃for 5 days.Secondly, MoPO-2(DETA) and MoPO-2(TEPA) were synthesized in the hydrothermal system with diethylenetriamine and tetraethylenepentamine as templates, respectively. The former optimal synthetic condition is MoO3: H3PO4: DETA: H2O=1.0: 2.0: 1.2: 83.3 at 210℃for 3 days. The latter optimal synthetic condition is MoO3:H3PO4: TEPA: H2O=1.0: 2.5: 0.3: 66.7 at 210℃for 3 days.Finally, MoPO-3(piperazine) was synthesized in the hydrothermal system with piperazine as a template. The optimal synthetic condition is MoO3: H3PO4: piperazine: H2O=1.0: 16.6: 0.3: 91.6 at 220℃for 6 days.