CO2 Hydrogenation to Ethanol over Cu@Na-Beta

Summary Here, we report a high-performance catalyst Cu@Na-Beta, prepared via a unique method to embed 2∼5 nm Cu nanoparticles in crystalline particles of Na-Beta zeolite, for CO2 hydrogenation to ethanol as the only organic product in a traditional fixed-bed reactor. The ethanol yield in a single pass can reach ∼14% at 300°C, ∼12,000 mL·gcat−1·h−1, and 2.1 MPa, corresponding to a space-time yield of ∼398 mg·gcat−1·h−1. The key step of the reaction is considered as the rapid bonding of CO2∗ with surface methyl species at step sites of Cu nanoparticles to CH3COO∗ that converts to ethanol in following hydrogenation steps. The points of the catalyst seemed to be that the irregular copper nanoparticles stuck in zeolitic frameworks offer high density of step sites and the intimate surrounding of zeolitic frameworks strongly constrain the CO2 reactions at the copper surface and block by-products, such as methanol, formic acid, and acetyl acid.