Pre-reduction and K loading effects on noble metal free Co-system catalyst for water gas shift reaction

Water gas shift (WGS) reaction over a noble metal free Co-system catalyst was investigated. Although K/Co₃O₄ showed no WGS activity with no pre-treatment, it showed high and stable activity after reduction by CO + H₂ (syngas). Moreover, the high activity was retained even after post-treatment in water vapor. Characterization of the catalyst was conducted using XRD, XPS, and XAFS, which revealed that conducting pre-reduction, especially using CO + H₂ caused the formation of Co₂C, which is a potential candidate as an active site, and that K donated electrons during reduction to form stable Co₂C, suppressing the formation of metallic Co. The catalyst has high competence in activity with noble metal WGS catalysts and conventional LTS catalyst, which can be a promising candidate for a WGS reaction catalyst.