US 12,448,289 B2
Method of nitrogen-phosphorus doped porous carbon for oxygen reduction electrocatalysis within a wide PH range
Lang Xu, Xuzhou (CN); Jiawei Qi, Xuzhou (CN); Haishen Jiang, Xuzhou (CN); Peiyao Bai, Xuzhou (CN); Weiqi Liu, Xuzhou (CN); Bailin Jin, Xuzhou (CN); and Wendu Zhang, Xuzhou (CN)
Assigned to China University of Mining and Technology, Xuzhou (CN)
Appl. No. 17/775,736
Filed by China University of Mining and Technology, Xuzhou (CN)
PCT Filed Jun. 11, 2021, PCT No. PCT/CN2021/099599
§ 371(c)(1), (2) Date May 10, 2022,
PCT Pub. No. WO2022/142155, PCT Pub. Date Jul. 7, 2022.
Claims priority of application No. 202011600692.5 (CN), filed on Dec. 30, 2020.
Prior Publication US 2023/0271833 A1, Aug. 31, 2023
Int. Cl. C01B 32/05 (2017.01)
CPC C01B 32/05 (2017.08) [C01P 2002/70 (2013.01); C01P 2002/82 (2013.01); C01P 2002/85 (2013.01); C01P 2004/03 (2013.01); C01P 2004/04 (2013.01); C01P 2006/12 (2013.01); C01P 2006/14 (2013.01); C01P 2006/40 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A preparation method of nitrogen-phosphorus doped porous carbon material for oxygen reduction electrocatalysis within a wide pH range, comprising:
(1) cleaning and drying natural mineral-based carbon sources, and mixing the natural mineral-based carbon sources for ball milling; pre-carbonizing the obtained mixture in a shielding gas; washing the pre-carbonized mixture with 2-3 mol ·L−1 potassium hydroxide solution at 80-90° C. for 1-3 hours, filtering, and re-washing with water till the filtrate is neutral; pickling the washed pre-carbonized mixture with 4-6 mol·L−1 hydrochloric acid solution at 50-60° C. for 1-3 hours, filtering, washing with water till the filtrate is neutral, and drying the pickled product;
(2) weighing the product to be doped from step (1) or (3), a nitrogen dopant and an activator respectively at a mass ratio of 1: (2-6): (1-3), milling and mixing, and transferring the mixture into a tube furnace, carbonizing at 850-1,050° C. for 1-4 hours in a nitrogen atmosphere at a heating rate of 2-20° C. ·min−1, taking out the resultant product after the carbonization is finished, and then pickling, filtering, washing with water, and drying, so that a nitrogen-doped carbon is obtained;
(3) weighing the product to be doped from step (1) or (2) and a phosphorus dopant respectively at a mass ratio of 1: (3-5), adding water for dilution and mixing, drying and transferring the mixture into a tube furnace, carbonizing at 850-1,050° C. for 1-4 hours in a nitrogen atmosphere at a heating rate of 2-20° C.·min−1, and pickling, filtering, washing with water, and drying, so that a phosphorus-doped carbon is obtained; and
(4) pickling the secondarily carbonized product obtained through the above steps in a sequence of (1), (2) and (3) or (1), (3) and (2) with 1 mol·L−1 dilute hydrochloric acid solution at 40-60° C. for 1-3 hours, filtering, washing with water till the filtrate is neutral, and drying;
(5) producing a nitrogen-phosphorus doped porous carbon material having a specific surface area in a range of 800 to 1300 m2·g−1, wherein a specific surface area of micropores is in a range of 500 to 700 m2·g−1 and a specific surface area of mesopores in a range of 100 to 800 m2·g−1, and wherein the nitrogen-phosphorus doped porous carbon material comprises a nitrogen content and phosphorus content of 2.64% and 2.42% respectively, a ratio of graphite nitrogen to pyridine nitrogen in the range of 1.5 to 3, and a ratio of P-C bonds to P-O bonds in the range of 1 to 2.5.