Chinese scientists have uncovered the crucial atomic-scale mechanism behind water's remarkable ability to boost platinum (Pt)-catalyzed biomass conversion, according to a recent research article published in the Journal of the American Chemical Society.
Biomass, one of the Earth's most abundant renewable resources, can be catalytically converted into fuels and chemicals to replace fossil-based products — a crucial pathway toward achieving carbon neutrality. This transformation relies heavily on processing furanic compounds, key platform molecules whose conversion requires selective cleavage of their stable furan ring's C-O bonds to produce valuable chain alcohols, carboxylic acids, and amines.
Previous experiments have consistently demonstrated that Pt-catalyzed furan ring-opening hydrogenation proceeds remarkably faster in water than in organic solvents with distinct product selectivity. However, the atomic-scale mechanism behind water's dramatic catalytic enhancement remains elusive.
To solve this puzzle, the research team led by Prof. ZHANG Jian from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences, in collaboration with Prof. William A. Goddard III from the California Institute of Technology, uncovered water's dual role as both a "proton shuttle" and "nucleophile" by combining isotope kinetic experiments with quantum mechanics calculations.
Their groundbreaking findings reveal a detailed "water-mediated pathway". Water participates directly in reductive C−O bond scission through proton-transfer assistance, activating a low-energy barrier path. Functioning as nucleophiles, water molecules attack the C(2) carbon atom, inducing hydroxyl migration in the intermediate, which is then sequentially hydrogenated to yield chain alcohols.
Throughout this catalytic cycle, hydronium ions spontaneously form at the metal/water interface, indirectly influencing reaction mechanism and kinetics.
"Understanding solvent's catalytic role provides critical insights for advancing complex liquid-solid catalytic processes," said corresponding author Prof. ZHANG. "This enables us to design more efficient biomass conversion processes for sustainable chemical production."
The findings provide crucial theoretical support for the industrial-scale green production of bio-based chemicals.
This work was supported by the National Natural Science Foundation of China (No. U23A20125), and the Natural Science Foundation of Ningbo (No. 2023J335), among others.
The platinum-catalyzed biomass conversion through a water-mediated pathway (Image by NIMTE)
Contact
ZHANG Jian
Ningbo Institute of Materials Technology and Engineering
E-mail: jzhang@nimte.ac.cn