The Scott group is using X-ray absorption spectroscopy and other methods appropriate for solid catalysts to investigate the nature of the active sites in heterogeneous Cu-containing catalysts, including supported molecular catalysts and Cu-doped porous metal oxides. These catalysts are being developed by CenSURF researchers for lignin disassembly and CO2 reduction. The insights we generate by studying both the freshly-prepared and used catalysts, as well as in situ measurements under reaction conditions, are being used to inform both experiments and calculations aimed at elucidating mechanisms and improving catalyst performance.