Yu-Cheng Wang

S‐Doping of an Fe/N/C ORR Catalyst for Polymer Electrolyte Membrane Fuel Cells with High Power Density

Fe/N/C is a promising non-Pt electrocatalyst for the oxygen reduction reaction (ORR), but its catalytic activity is considerably inferior to that of Pt in acidic medium, the environment of polymer electrolyte membrane fuel cells (PEMFCs). An improved Fe/N/C catalyst (denoted as Fe/N/C-SCN) derived from Fe(SCN)3, poly-m-phenylenediamine, and carbon black is presented. The advantage of using Fe(SCN)3 as iron source is that the obtained catalyst has a high level of S doping and high surface area, and thus exhibits excellent ORR activity (23 A g(-1) at 0.80 V) in 0.1 M H2SO4 solution. When the Fe/N/C-SCN was applied in a PEMFC as cathode catalyst, the maximal power density could exceed 1 W cm(-2).

Three-Dimensional Networks of S-Doped Fe/N/C with Hierarchical Porosity for Efficient Oxygen Reduction in Polymer Electrolyte Membrane Fuel Cells

Reasonable design and synthesis of Fe/N/C-based catalysts is one of the most promising way for developing precious metal-free oxygen reduction reaction (ORR) catalysts in acidic mediums. Herein, we developed a highly active metal-organic framework-derived S-doped Fe/N/C catalyst [S-Fe/Z8/2-aminothiazole (2-AT)] prepared by thermal treatment. The S-Fe/Z8/2-AT catalyst with uniform S-doping possesses a three-dimensional macro-meso-micro hierarchically porous structure. Moreover, the chemical composition and structural features have been well-optimized and characterized for such S-Fe/Z8/2-AT catalysts; and their formation mechanism was also revealed. Significantly, applying the optimal S-Fe/Z8/2-AT catalysts into electrocatalytic test exhibits remarkable ORR catalytic activity with a half-wave potential of 0.82 V (vs reversible hydrogen electrode) and a mass activity of 18.3 A g-1 at 0.8 V in 0.1 M H2SO4 solution; the polymer electrolyte membrane fuel cell test also confirmed their excellent catalytic activity, which gives a maximal power density as high as 800 mW cm-2 at 1 bar. A series of designed experiments disclosed that the favorable structural merits and desirable chemical compositions of S-Fe/Z8/2-AT catalysts are critical factors for efficient electrocatalytic performance. The work provides a new approach to open an avenue for accurately controlling the composition and structure of Fe/N/C catalysts with highly activity for ORR.