Guo Chaozhong, Sun Lingtao, Liao Wenli, Li Zhongbin
Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Yongchuan 402160, Chongqing, China.
College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences, Yongchuan 402160, Chongqing, China.
Materials (Basel). 2015 Dec 23;9(1):1. doi: 10.3390/ma9010001.
The development of highly stable and efficient electrocatalysts for sluggish oxygen reduction reaction (ORR) is exceedingly significant for the commercialization of fuel cells but remains a challenge. We here synthesize a new nitrogen-doped biocarbon composite material (N-BC@CNP-900) as a nitrogen-containing carbon-based electrocatalyst for the ORR via facile all-solid-state multi-step pyrolysis of bioprotein-enriched enoki mushroom as a starting material, and inexpensive carbon nanoparticles as the inserting matrix and conducting agent at controlled temperatures. Results show that the N-BC@CNP-900 catalyst exhibits the best ORR electrocatalytic activity with an onset potential of 0.94 V ( reversible hydrogen electrode, RHE) and high stability. Meanwhile, this catalyst significantly exhibits good selectivity of the four-electron reaction pathway in an alkaline electrolyte. It is notable that pyridinic- and graphtic-nitrogen groups that play a key role in the enhancement of the ORR activity may be the catalytically active structures for the ORR. We further propose that the pyridinic-nitrogen species can mainly stabilize the ORR activity and the graphitic-nitrogen species can largely enhance the ORR activity. Besides, the addition of carbon support also plays an important role in the pyrolysis process, promoting the ORR electrocatalytic activity.
开发用于缓慢氧还原反应（ORR）的高稳定性和高效电催化剂对于燃料电池的商业化极为重要，但仍然是一个挑战。我们在此通过以富含生物蛋白的金针菇为起始材料，在可控温度下以廉价的碳纳米颗粒作为插入基质和导电剂，通过简便的全固态多步热解合成了一种新型氮掺杂生物碳复合材料（N-BC@CNP-900）作为用于ORR的含氮碳基电催化剂。结果表明，N-BC@CNP-900催化剂表现出最佳的ORR电催化活性，起始电位为0.94 V（可逆氢电极，RHE）且具有高稳定性。同时，该催化剂在碱性电解质中显著表现出对四电子反应途径的良好选择性。值得注意的是，在增强ORR活性中起关键作用的吡啶型和石墨型氮基团可能是ORR的催化活性结构。我们进一步提出，吡啶型氮物种主要稳定ORR活性，而石墨型氮物种可大大增强ORR活性。此外，碳载体的添加在热解过程中也起着重要作用，促进了ORR电催化活性。
