Relay semi-hydrogenation of acetylene via hydrogen spillover on non-reducible Al<sub>2</sub>O<sub>3</sub>-supported single-atom catalysts.
basic_science · Level V
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- Record sourced from PubMed, PMID 42303643.
- Also identified by DOI 10.1038/s41467-026-74503-0.
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Abstract
Hydrogen spillover involves the migration of hydrogen atoms from metal to another component, yet it remains challenging to achieve on non-reducible supports. This paper describes the observation of hydrogen spillover on non-reducible Al<sub>2</sub>O<sub>3</sub>-supported Pd single-atom catalysts, facilitated by phosphorus-hydroxyl (P-OH) bridge sites, for acetylene semi-hydrogenation. Through in situ spectroscopy, kinetic analysis, and computational analyses, we show that Pd single atoms promote the heterolytic activation of H<sub>2</sub>, while phosphorus doping on Al<sub>2</sub>O<sub>3</sub> lowers energy barrier for hydrogen spillover via the formation of P-OH species. Gas-phase acetylene collides and hydrogenates with as-formed P-OH, following Eley-Rideal type mechanism, making inert Al<sub>2</sub>O<sub>3</sub> active in hydrogenation reaction. This unconventional relay pathway reduced Pd usage by one order of magnitude and improved catalytic stability, with over 95% ethylene selectivity at 99% acetylene conversion in ethylene-rich stream at 100 °C for more than 200 hours. This work elucidates the mechanism of hydrogen spillover on non-reducible Al<sub>2</sub>O<sub>3</sub> and relay hydrogenation on supported single-atom catalysts.