Bimetallic Metal Sites\nin Metal–Organic Frameworks\nFacilitate the Production of 1‑Butene from Electrosynthesized\nEthylene

Abstract

Converting\nCO₂ to synthetic hydrocarbon fuels\nis of\nincreasing interest. In light of progress in electrified CO₂ to ethylene, we explored routes to dimerize to 1-butene, an olefin\nthat can serve as a building block to ethylene longer-chain alkanes.\nWith goal of selective and active dimerization, we investigate a series\nof metal–organic frameworks having bimetallic catalytic sites.\nWe find that the tunable pore structure enables optimization of selectivity\nand that periodic pore channels enhance activity. In a tandem system\nfor the conversion of CO₂ to 1-C₄H₈, wherein the outlet cathodic gas from a CO₂-to-C₂H₄ electrolyzer is fed directly (via a dehumidification\nstage) into the C₂H₄ dimerizer, we study the\nhighest-performing MOF found herein: M′ = Ru and M″\n= Ni in the bimetallic two-dimensional M′₂(OAc)₄M″(CN)₄ MOF. We report a 1-C₄H₈ production rate of 1.3 mol g_cat^–1 h^–1 and a C₂H₄ conversion\nof 97%. From these experimental data, we project an estimated cradle-to-gate\ncarbon intensity of −2.1 kg-CO₂e/kg-1-C₄H₈ when CO₂ is supplied from direct air capture\nand when the required energy is supplied by electricity having the\ncarbon intensity of wind.