Effects of hydrogen spillover on CO2 hydrogenation over Pt-Co-Al based catalysts

Abstract

CO₂ hydrogenation presents a crucial pathway for carbon circularity. The activation, adsorption, and hydrogen spillover are key processes in CO₂ hydrogenation. This study investigates the effects of hydrogen spillover induced by Pt on CO₂ hydrogenation over Pt-promoted Co-Al catalysts. A series of Pt-promoted Co-Al catalysts were synthesized via co-precipitation and employed for CO₂ hydrogenation. The optimized Pt-promoted Co-Al catalyst efficiently converts CO₂, leading to the formation of methane (46.6 mmol g_cat⁻¹ h⁻¹), methanol (509.4 μmol g_cat⁻¹ h⁻¹), and higher alcohols (220.6 μmol g_cat⁻¹ h⁻¹). The Pt-promoted Co-Al catalysts facilitate hydrogen spillover, optimizing the catalysts’ reducibility and exposing more active sites. Moreover, the hydrogen adsorption is weakened due to the Pt induced hydrogen spillover, which facilitates the formation of *HCOO, *CH₃, and *CO intermediates. This in turn facilitate the coupling between *HCOO/*CO and *CH₃, enhancing the formation of higher alcohols.