Synthesis of Na@nanoFAU Zeolite Catalyst and Catalysis for Production of Formic Acid with Na@nanoFAU

Abstract: Microporous aluminosilicate is one type of most important catalyst supports in catalysis reactions performed at high temperatures in gas phase and at a relatively low temperature in a liquid phase. There is significant limit of diffusion resulting from long diffusion path of molecules in a particle of aluminosilicate with a size of a few hundreds of nanometers and from the limited pore diameter of subnanometer when a catalytic reaction is performed in the micropores of aluminosilicate buried in liquid phase at a low temperature (< 200 °C). To avoid such diffusion limit, FAU at nanoscale (nanoFAU) was synthesized through growth of layered porous aluminosilicate in confined space between adjacent graphene oxide layers and a following removal of the graphene oxide through combustion at a high temperature. The as-synthesized nanoFAU exhibits a lateral dimension of tens of nanometers but a thickness of only 2–3 nm in terms of a single unit cell of zeolite. The Na ⁺ cations anchored on Brønsted site in micropores of the as-synthesized nanoFAU exhibit (Na@nanoFAU) is active for synthesis of formic acid from CO and H ₂ O in aqueous solution under the gas phase of 10 bar CO. The apparent activation barrier for synthesis of formic acid on this Na@nanoFAU is about 50.1 kJ/mol. Graphical Abstract: [Figure not available: see fulltext.]