Atomically dispersed Co on MgAlO boosting C alcohols selectivity of ethanol valorization

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 25; no. 7; pp. 2653 - 2662
• Main Authors: Lv, Wen-Lu, He, Lei, Li, Wen-Cui, Zhou, Bai-Chuan, Lv, Shao-Pei, Lu, An-Hui
• Format: Journal Article
• Published: 03.04.2023
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d3gc00078h

Catalytic upgrading of biomass-derived ethanol to C 4+ compounds through C-C coupling is an essential green and sustainable approach towards value-added fine chemicals. Developing catalysts to improve the selectivity of C 4+ compounds is highly desired due to the complex transformation of ethanol affording diverse species. Here, we report atomically dispersed Co 2+ on MgAlO x as catalysts derived from layered double hydroxide (LDH) precursors for the dehydrogenation coupling of ethanol to C 4-10 alcohols. The selectivity for C 4-10 alcohols reaches 95.4% with 32.9% ethanol conversion over the optimal catalyst, Co 0.15 Mg 2.85 AlO x , at 523 K and 0.1 MPa. A yield of 31.4% is greatly higher than that (∼15%) over most of the state-of-the-art catalysts. Characterization techniques including XRD, XPS, UV-Vis and CO-IR reveal that the atomically dispersed Co 2+ in the lattice of MgAlO x is originated from the replacement of Mg in the LDH precursor and remain stable during the reactions. Both increments of basic and acid sites are observed after Co 2+ replacement according to the TPD-MS measurements of CO 2 and NH 3 . The introduction of an appropriate amount of Co 2+ effectively facilitates the dehydrogenation step, thus, high activity under milder conditions. Meanwhile, abundant basic and acid sites boost the following aldol condensation step resulting in ultra-high C 4-10 selectivity. These findings can shed light on sustainable heterogeneous catalytic processes. Atomically dispersed Co 2+ on MgAlO x derived from CoMgAl-LDH was offered in a one-pot catalytic transformation of ethanol into the C 4-10 alcohols process, which could boost the C 4-10 alcohols yield of ethanol valorization at relatively low temperature.