High-performance Pt/CeO2-ZrO2 catalysts for selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols under mild reaction conditions: “Giant” hydrogen spillover behind the activity enhancement

•Giant H2 spillover occurs on Pt/CeO2-ZrO2 with Pt of 0.025–1 % wt. at −50 - +25 °C.•H2 spillover leads to Ce3+ sites formation for C = O bond activation in aldehyde.•Pt/CeO2-ZrO2 system is more active and selective than Pt/C, Pt/SiO2, Pd/C.•1H MAS SS NMR detects hydrogen in activated hydride state on Pt/CeO2-ZrO2.•not activated H2 with no spillover is observed on 1 %Pt/SiO2 by 1H MAS SS NMR.