Hydrogenolysis of alkali lignin using spent cell-phone battery electrode coating derived lithium cobalt oxide on carbon catalyst

Hydrogenolysis of plentiful lignin offers a sustainable approach to producing aromatic renewable feedstocks and intermediates for biofuels. This study demonstrates that a low-cost catalyst derived from Li-ion cell-phone battery waste can serve as an excellent substitute to expensive noble metal catalysts for the hydrogenolysis of alkali and methanol-fractionated lignin, yielding phenols. Catalyst was prepared by pyrolyzing the electrode coating in spent Motorola SNN5749A, 3.6 V cellphone batteries at 600 °C in air and was characterized as LiCo 0.9 O x on graphite carbon using elemental analysis, SEM, EDX, XRD and XPS. The hydrogenolysis of alkali lignin and methanol fractionated alkali lignin in methanol produced liquefaction yields of 62 and 73% respectively in a process using 10% catalyst loading (w/w), 5.5 MPa H 2 , 300 °C for 4.0 h. The major products obtained from alkali lignin were 2-methoxy-phenol ( o -guaiacol), 4-methyl-phenol ( p -cresol) and 4-methoxy-phenol ( p -guaiacol) in 35, 25 and 15% selectivities, respectively. The same three major products were observed in hydrogenolysis of MeOH fractionated alkali lignin in 34, 27 and 20% selectivities. Reuse of LiCo 0.9 O x /C catalyst showed a small gradual decline in catalytic activity resulting in a 73 to 58% decrease in MeOH fractionated alkali liquefaction yield after four cycles.