title: Sulfur-nitrogen co-doped three-dimensional carbon foams with hierarchical pore structures as efficient metal-free electrocatalysts for oxygen reduction reactions.
abstract: Despite the good progress in developing doped carbon catalysts for oxygen-reduction reaction (ORR), the current metal-free carbon catalysts are still far from satisfactory for large-scale applications of fuel cell. Developing new metal free doped carbon materials with abundance active sites as well as excellent electron transfer and reactant transport rate towards ORR may be a potential solution. Herein, we develop a novel three-dimensional (3D) sulfur-nitrogen co-doped carbon foams (S-N-CF) with hierarchical pore structures, using a convenient, economical, and scalable method. The experimental results have demonstrated that the obtained 3D S-N-CF exhibited better catalytic activity, longer-term stability and higher methanol tolerance than a commercial Pt/C catalyst. Such excellent performances may be attributed to the synergistic effect, which includes high catalytic sites for ORR provided by high S-N heteroatom loading, excellent reactant transport caused by hierarchical pore structures and high electron transfer rate provided by 3D continuous networks. Our results not only develop a new type of catalysts with excellent electrocatalytic performance by a commercially valid route, but also provide useful information for further clarification of the relationship between the microstructures of metal-free carbon materials and catalyst properties for ORR. More importantly, the idea to design hierarchical pore structures could be applied to other catalytic materials and serve as a general strategy for improving the activity of various ORR catalysts.
authors.affiliation: Nanomaterials and Chemistry Key Laboratory, Wenzhou University, Wenzhou, 325027, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Huagui
authors.initials: H
authors.lastname: Nie
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Jin
authors.forename: Yanqi
authors.initials: Y
authors.lastname: Lu
authors.forename: Zhubing
authors.initials: Z
authors.lastname: Xiao
authors.forename: Shaoming
authors.initials: S
authors.lastname: Huang