University of Rochester
Department of Chemical Engineering
Reverse water-gas shift (RWGS) followed by Fischer-Tropsch synthesis (FTS) is a potential pathway for transforming CO2 into value-added chemicals and fuels. The combined RWGS-FTS reaction pathway is currently being investigated for the seawater-to-fuel process, which uses CO2 and H2 produced via electrolysis of seawater and is ideally powered by nuclear or renewable energy. Synthesis of fuels through a renewable process not only benefits the circular carbon economy, but also may provide U.S. Navy carrier groups with a strategic advantage when they
operate away from the mainland. We recently developed a highly selective K-Mo2C RWGS catalyst, which can achieve >99% CO selectivity at 450 °C and a GHSV of 132,000 mL/g/h. Under these conditions, the RWGS effluent contains ~50% unreacted CO2 after water removal, which presents a challenge for downstream fuel synthesis via FTS. Instead of separating the CO from CO2 via traditional methods, we are developing catalysts for reactive separations of CO/CO2 mixtures over single- atom alloy (SAA) Ru-Co catalysts. Aberration corrected-transmission electron microscopy (AC-TEM) and H2-temperature-programmed reduction (TPR) illustrate that the Ru single atoms are well-dispersed on the surface of Co nanoparticles, and the Ru single atoms decrease the reduction temperature of Co. Density functional theory (DFT) calculations of segregation energies agree with AC-TEM observations, and simulated reaction pathways of -CH- coupling and dissociation illustrate that Ru dopants may slow alkane-chain growth without affecting chain termination. Our results suggest that the Ru atoms in the Ru-Co SAA preserve Co in a reduced phase under reaction conditions and are promising catalysts for reactive separations of CO/CO2 mixtures.
Professor Marc Porosoff received his BS in 2009 and MS in 2010, both in Chemical and Biomolecular Engineering from the Johns Hopkins University. In 2015, he completed his PhD in Chemical Engineering at Columbia University, with a thesis on developing catalysts for carbon dioxide conversion. Porosoff then worked as a National Research Council sponsored postdoctoral fellow at the Naval Research Laboratory on the ‘Seawater to Fuel’ project. At Rochester, Porosoff plans to investigate low-cost, alternative catalysts for CO2 hydrogenation and natural gas conversion into value-added chemicals and fuels. Porosoff’s research targets relationships between chemical reactivity and catalyst electronic/structure properties through reactor studies, XAFS, XPS, XRD, CO chemisorption, and in situ FTIR and XAFS measurements. Porosoff will be teaching a new graduate-level reactor design course starting in Spring of 2018 and Green Energy (CHE 150) in Fall of 2018.