This research aims to create novel, resilient, inexpensive, active, and selective catalyst materials to concurrently conquer current constraints and achieve an efficient, scalable, and intensified non-oxidative methane conversion (NMC).
University of Maryland, College Park, MD 20742
The catalysts proposed in this project are made of isolated single metal atoms supported in a silica matrix and operated at medium-high temperatures (900-1100 °C). The isolation of metal atoms achieves methane activation by heterogeneous surface dehydrogenation to generate a hydrocarbon pool and hydrogen species, followed by C-C coupling on the active sites, and limits coke formation due to the absence of metal atom ensembles. The high reaction temperature induces homogeneous gas-phase reactions to form dehydrogenated and cyclized C2+ products. The integration of novel single atom catalysts for NMC initiation with homogeneous reactions in a microreactor (e.g., a catalytic wall reactor) will enable unprecedented NMC performance. The objectives of this project are to: 1) synthesize isolated single atoms of various metals in a silica matrix to prove universality of these catalysts in CH4 activation; 2) utilize a wide range of experimental and computational techniques to probe in situ and operando the surface and bulk structure/property of the NMC catalysts; 3) mechanistically understand the reaction network by an integrated experimental and computational effort to identify rigorously species, temperature, and kinetics; and 4) validate and scale-up synthesis of robust catalysts and reactors for efficient NMC of natural gas guided by validated process modeling. The proposed system is designed to run at single-pass CH4 conversion and C2+ yields of >25%, with > 90% C2+ selectivity, and a lifetime of >1000h.
While methane, the primary component of natural gas, is a source of energy and economic growth, it can also be an environmental concern. Recent developments in horizontal drilling as well as enhanced extraction methods have resulted in production of an estimated 62.4 trillion m3 of ‘stranded’, or uneconomic, natural gas. Associated gas is often flared or vented at remote oil production sites. Leaked, flared, and/or vented gas represents a lost opportunity and reduces domestic energy security. To address this problem, the University of Maryland College Park (UMD) and the University of Delaware (UD) propose to develop transformative isolated single atom metal/silica (M/SiO2) catalysts and an intensified catalytic wall reactor technology to convert CH4 to value-added C2+ and H2 products.
The team is conducting in-situ characterizations on the methane activation over the Fe/SiO2 catalyst in both fixed-bed and catalytic wall reactor settings in a customized capillary sampling system connected to a process mass spectrometer. The study will reveal the contributions from gas phase and surface reactions to the measured conversions. The catalytic performance of the catalysts with different compositions in the induction period of NMC are being studied. The studies for pushing high methane conversions in the catalytic wall reactor is ongoing. The computational calculations for optimizing catalyst and reactor operation conditions are being conducted.