Electroreductive CO coupling provides a prospective strategy for biomass derivative upgrading via reducing the number of oxygen-containing functional groups and increasing their molecular weight. However, exploring superior electrocatalysts with effective reactivity and high selectivity for target products are still a challenge. In this work, single atom Au surface derived NiMn2O4 (SACs Au-NiMn2O4) spinel synergetic composites were fabricated by a versatile adsorption-deposition method and applied in electroreductive self-coupling of benzaldehyde to dibenzyl ether. The SACs Au-NiMn2O4 spinel synergetic composites enhanced electroreductive coupling of benzaldehyde, significantly improved the yield and selectivity of dibenzyl ether. Systematic characterizations and density functional theory calculation revealed that atomically dispersed Au occupied surface Ni2+ vacancies, which played a dominated role in CO coupling of benzaldehyde. Detailed calculation results showed that benzaldehyde preferred to adsorb on Ni octa-hedral sites of NiMn2O4 spinel synergetic structure, single atom Au surficial derivation over NiMn2O4 further reduced the adsorption energy (Eads) of benzaldehyde on SACs Au-NiMn2O4, thus the CO coupling of benzaldehyde to dibenzyl ether was promoted. Moreover, single atom Au surficial derivation lowered the energy barrier of rate-determining step, facilitated the formation of dibenzyl ether species. Our work also paves an avenue for rational design single atom materials using spinel as support.
Keywords: Benzaldehyde CO coupling; Biomass upgrading; Dibenzyl ether production; Mechanism research; SACs Au−NiMn(2)O(4).
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