Interface-controlled synthesis of nickel phyllosilicate for efficient CO2 hydrogenation to methane: Breaking limitation of the conventional silica-surface-controlled synthesis

The conventional synthesis of Ni-phyllosilicate occurs on the surface of silica material via the reaction between SiO2 species and nickel salt. This process greatly relies on the silica surface, which results in a thick layer and low catalytic activity of Ni-phyllosilicate. To overcome this limitation, we propose an interface-controlled synthesis of Ni-phyllosilicate using tetraethyl orthosilicate and nickel nitrate as precursors. In this method, an emulsification system is created using a dual solvent of H2O and n-heptane, along with the emulsifier oleylamine. The Niphyllosilicate can only form at the liquid-liquid phase interface of the microemulsion droplet, resulting in an extremely thin layer with a thickness of just 0.72 f 0.20 nm. Consequently, the optimal NiPs-60-S-15 catalyst exhibits a competitive CO2 conversion of 85.23 f 0.50 % at 400 degrees C, 60 L center dot g- 1 center dot h-1, 0.1 MPa, with a high turnover frequency for CO2 (TOFCO2, 3.6 f 0.01 x 10-2 s- 1) and low activation energy of 66.60 f 0.20 kJ center dot mol- 1. Importantly, it maintains high stability for 100 h and exhibits strong resistance to Ni sintering. Overall, this study breaks limitation of the traditional silica-surface-controlled synthesis of Ni-phyllosilicate and introduces a novel interface-controlled method for synthesizing materials with small sizes and thin layers.