In their study, the researchers solved the challenge of discovering the right catalytic pathway for using ethane to convert CO2 into gas for generating electricity, liquid fuels, or ethylene.Converting carbon dioxide (CO2) and ethane—an underutilized component of natural gas—into chemicals with higher value would allow us to make use of a potent greenhouse gas and an unused reservoir of hydrocarbons. But ensuring such reactions specifically lead to one desired product or another can be a challenge.
A team of researchers discovered the underlying principles that determine the behavior of catalysts—the chemical “deal makers” that bring reactants together—thereby providing the key to more selective reactions. The team specifically investigated the catalytic selectivity for one set of reactions: transforming CO2 and ethane (C2H6) into synthesis gas (useful for generating electricity or making liquid fuels) or, alternatively, ethylene (a building block for making paints, plastics, and other polymers).
To discover the key principles, the team conducted detailed studies of a series of bimetallic (two-metal) catalysts—using different metals paired with palladium. For each combination, they examined how the metals come together and measured how the mix of reactants and products changes during the reaction. The team collaborated with staff scientists at the National Synchrotron Light Source II (NSLS-II), the Center for Functional Nanomaterials (CFN), and the Advanced Photon Source (APS)—three DOE Office of Science user facilities at Brookhaven and Argonne National Laboratory, respectively—to study the catalysts’ atomic structures and electronic properties using powerful x-rays. At the NSLS-II, the team specifically turned to the Inner-Shell Spectroscopy (ISS) and Quick X-ray Absorption and Scattering (QAS) beamlines for in situ x-ray absorption studies, while they used diffraction techniques at the APS.