A novel and efficient N-doping carbon supported cobalt catalyst derived from the fermentation broth solid waste for the hydrogenation of ketones via Meerwein-Ponndorf-Verley reaction

Most of the non-noble metal catalysts used for the Meerwein-Ponndorf-Verley (MPV) reaction of carbonyl compounds rely on the additional alkaline additives during preparation to achieve high efficiency. To solve this problem, in this work, we prepared a novel N-doped carbon supported cobalt catalyst (Co@CN), in which the carriers were derived from the nitrogen-rich organic waste, i.e., oxytetracycline fermentation residue (OFR, obtained from oxytetracycline refining workshop). No additional nitrogen sources were used during preparation. The results showed that inherent nitrogen in OFR could provide N-containing basic sites, and formed Co-N structures via coordinating with cobalt. The Co-N sites together with the coexisting Co-(0) cooperated to catalyze the conversion of ethyl levulinate (EL) to gamma-valerolactone (GVL) by MPV reaction. Co-(0) dominated the activation of H in isopropanol, while Co-N dominated the formation of the six-membered ring transition state.