Preparation of S, N codoped lignin composite iron phthalocyanine as an efficient oxygen reduction reaction catalyst by one-pot method and application to high-performance lignin fuel cells.

Lignin fuel cells have received widespread attention due to their high energy conversion efficiency and green environmental protection. However, lignin fuel cells limit practical applications due to high catalyst costs and low power generation efficiency. Therefore, this study prepared three-dimensional composite catalysts with nitrogen-doped reduced graphene oxide (NrGO), sulfur and nitrogen-doped lignin, and iron phthalocyanine (FePc). The catalyst showed good catalytic activity for the oxygen reduction reaction (ORR) with a half-wave potential of 0.81 V, a 4-electron transfer. The catalysts also showed better stability and resistance to methanol toxicity. The catalyst applied to a lignin liquid stream fuel cell showed an open-circuit voltage of 1.23 V and a maximum power density of 151.6 mW cm-2 while being able to light LEDs. When lignin is discharged as a fuel, the cracking products are mainly phenol and vanillin. Lignin fuel cells with simple catalyst preparation and high power generation efficiency have the potential for practical applications.