386 / 2018-07-31 23:57:18

Preparation of nitrogen and phosphorus co-doped biochar for electrochemical oxygen reduction reaction

全体主题 > 生物质发电

In non-metallic oxygen reduction reaction (ORR) catalysts, nitrogen and phosphorus co-doped carbon materials show better catalytic activity than single heteroatom N-doped. Therefore, In this study, okara (a cheap, nitrogen-rich biomass) was choosed as precursor to prepare nitrogen and phosphorus co-doped biochar (N-P-B-X, X means the doping temperature) catalysts through hydrothermal and ammonium phosphate high-temperature doping. Specific surface area of the typical product (N-P-B-900) increased from less than 30 m2 g-1 to 689 m2 g-1 and N-P-B-900 processes porous structure, which means that more accessible sites are provided and also that is good for proton transfer. At the same time, N-P-B-900 has high nitrogen and phosphorus content after doping, achieving 5.47%, 3.04% respectively, and the active pyridine nitrogen content increased up to 25%. In addition, the electrochemical results show that N-P-B-900 has s positive onset potential 0.87V but lower limits current 4.6 cm-1 mA. Furthermore, N-P-B-900 reveals better tolerance to methanol poisoning effects and durability than commercial 20% Pt/C catalyst in alkaline solution, about 87.3% current left after 20000s chronoamperometry test. These attractive electrochemical properties indicate that nitrogen and phosphorus co-doped biochar is a promising catalyst for ORR.