High-Density Rare-Earth Single-Atom-Triggered Unconventional Transition of Adsorption Configuration on La1Pd Monatomic Alloy Metallene for Sustainable Electrocatalytic Alkynol Semi-Hydrogenation

Electrocatalytic alkynol semi-hydrogenation for the high-value chemicals alkenol with mild conditions and carbon-free emission is a potentially green and sustainable alternative to conventional thermocatalytic routes, which generally involves the design of electrocatalysts with high activity and high selectivity. Here, the rare-earth single-atom (Ln = La, Nd, Pr) coordinated Pd metallene (Ln 1 Pdene) is reported for electrocatalytic 2-methyl-3-butyn-2-ol (MBY) semi-hydrogenation reaction (MBY ESHR) to synthesis of 2-methyl-3-buten-2-ol (MBE). Typically, in alkaline medium containing 0.1 m MBY, MBY conversion and MBE selectivity of La 1 Pdene are as high as ≈97% and ≈95%, respectively, with excellent electrocatalytic stability. Meanwhile, in situ infrared spectra reveal the conversion of MBY to MBE during the dynamic electrocatalytic process. Theoretical calculations reveal that the interaction between La single-atom and Pd host triggers an unconventional transformation of the intermediate MBE* adsorption configuration during electrocatalytic hydrogenation, achieving the optimal desorption energy between La 1 Pd and target product and optimizing the reaction energy barriers to inhibit the over-hydrogenation of MBE. Moreover, La single-atom as the adsorption active site of the hydrogen supplier H 2 O effectively reduces the competition adsorption between the reactants MBY and H 2 O, rendering La single-atom and Pd host as the synergistic co-catalytic active sites to promote the electrocatalytic MBY semi-hydrogenation reaction.