Confinement of Ultrasmall Cobalt Oxide Clusters within Silicalite-1 Crystals for Efficient Conversion of Fructose into Methyl Lactate

Abstract

Chemocatalysis of sugars to methyl lactate (MLA) exhibits great advantages over the conventional fermentation approach because of its higher productivity and cost-effective separation process. However, widely used supported metal oxide catalysts suffer from deactivation resulting from sintering during the reaction and removal of coke at high temperatures. Herein, we report ultrasmall cobalt oxide clusters (∼1.7 nm) stabilized within silicalite-1 crystals catalyst (CoO@silicalite-1), exhibiting superior catalytic activity and resistance to sintering for the conversion of fructose into methyl lactate. HAADF-STEM, EDS-mapping, and XRD experiments identify the existence of confined CoO clusters. XANES and Raman spectra demonstrated the covalent interaction between CoO and silicalite-1. Thanks to the ultrasmall CoO particle size (∼1.7 nm), the CoO@silicalite-1 affords nearly 100-fold higher Co-mass-based activity (mg MLA/mg Co) compared with CoO or Co3O4 particles outside the silicalite-1 framework. More importantly, this catalyst exhibits good reuse performance via the removal of coke with facile calcination.

Sustainable access to renewable N-containing chemicals from reductive amination of biomass-derived platform compounds

“…Various carboxylic acids including lactic acid [182], succinic acid [183], glucaric acid [184], xylaric acid [185], itaconic acid [186] and formic acid [187] can be obtained from biomass-derived carbohydrates in high yields. Amongst these, lactic acid stands out due to the high market demand of biodegradable poly(lactic acid) and its function as a versatile intermediate for the production of many commodity chemicals [188,189].…”

Encapsulation of CuO nanoparticles within silicalite-1 as a regenerative catalyst for transfer hydrogenation of furfural

“…The XRD patterns of pristine sil-1 and 3CuO@sil-1 are shown in Figure 2 A exhibits the typical MFI-type zeolite structure, which is indicative of the formation of a sil-1 crystal structure ( Yan et al., 2019 ; Valtchev, 2002 ). The zeolitic five-membered ring structure can also be evidenced in the FTIR spectra in Figure 2 B with the characteristic peaks located at 551 and 1230 cm −1 .…”

Biomass valorisation over metal-based solid catalysts from nanoparticles to single atoms

“…Silicalite has been alternatively used to encapsulate sintering-resistant clusters of CoO for the conversion of fructose into methyl lactate. 50 Ultrasmall CoO NPs (B1.7 nm) were attained through a bottom-up steam-assisted method with Co loadings smaller than 2 wt% and led to nearly 100-fold higher Co-mass-based activity (mg methyl lactate mg Co Sn-containing beta zeolite applied to the more complex glucose-to-DHA conversion, i.e., an additional initial isomerisation step is required when starting from the aldose (Fig. 6a).…”