Preparation of nitrogen and sulfur co-doped ultrathin graphitic carbon via annealing bagasse lignin as potential electrocatalyst towards oxygen reduction reaction in alkaline and acid media

Abstract

Abstract Renewable lignin used for synthesizing materials has been proven to be highly potential in specific electrochemistry. Here, we report a simple method to synthesize nitrogen and sulfur co-doped carbon nanosheets by using bagasse lignin, denoted as lignin-derived carbon (LC). By adjusting the ratio of nitrogen source and annealing temperature, we obtained the ultrathin graphitic lignin carbon (LC-4-1000) with abundant wrinkles with high surface area of 1208 m2g−1 and large pore volume of 1.40 cm3g−1. In alkaline medium, LC-4-1000 has more positive half-wave potential and nearly current density compared to commercial Pt/C for oxygen reduction reaction (ORR). More importantly, LC-4-1000 also exhibits comparable activity and superior stability for ORR in acid medium due to its high graphitic N ratio and a direct four electron pathway for ORR. This study develops a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in fuel cells.