Thermal Behavior Of Mg-Ni-Phyllosilicate Nanoscrolls And Performance Of The Resulting Composites In Hexene-1 And Acetone Hydrogenation

Here we report on the thermal properties of Mg-Ni-phyllosilicate nanoscrolls as a promising precursor for production of Ni/silicate composite catalysts. Spontaneous scrolling of the phyllosilicate layer originating from size difference between metal-oxygen and silica sheets provides high surface area of the catalyst. Metal nanoparticles can be obtained directly from the matrix by H-2 reduction. The phyllosilicate structure passed through a number of transformations including partial dehydroxylation with formation of sepiolite-like phase followed by silicate or oxide crystallization. Temperature ranges of these transitions overlapped with the reduction process sophisticating the H-2 consumption profiles. In particular, some amount of Ni2+ got sealed up by the sepiolite structural features, that opened a path for the tuning of Ni-0 : Ni2+ ratio of the catalyst. An increase of Ni content in the system yielded a decrease in the metal nanoparticles sizes due to both high intensity of nucleation and type of residual matrix. Ni nanoparticles size distribution and specific surface area of the composite catalysts governed conversion rate of hexene-1 and acetone hydrogenation. In the view of the turnover frequency MgNi2Si2O5(OH)(4) precursors were slightly more preferable than pure Ni3Si2O5(OH)(4).