Al3d xps peak
Thus, this is a crucial issue in the development and application of FCs, namely, replacing precious and nondurable Pt-based catalysts with cheap and highly efficient materials for ORR. However, there are some vital problems still plaguing Pt-based catalysts such as high cost, limited quantity available, poor stability and susceptibility to methanol crossover. Currently, the platinum 3, 4, 5 (Pt) and Pt-based 6, 7, 8, 9, 10 catalysts are common for ORR. The sluggish kinetics of oxygen reduction reaction (ORR) at fuel cells (FCs) cathode seriously hinder the overall development of efficient energy storage and conversion devices 1, 2, so catalysts must be used to enhance the efficiency of fuel cells. Furthermore, the outstanding methanol tolerance and excellent long-term stability of NPS-C-MOF-5 are superior to those of the commercial Pt-C catalyst for ORR in alkaline media. In particular, the kinetic limiting current density of NPS-C-MOF-5 catalyst at −0.6 V is up to approximate −11.6 mA cm −2, which is 1.2 times higher than that of the commercial Pt-C catalyst. Due to the synergistic effect of N, P and S ternary-doping, the NPS-C-MOF-5 catalyst shows a higher onset potential as a metal-free electrocatalyst for ORR among the currently reported metal-free electrocatalysts, very close to the commercial Pt-C catalyst. The influences of porous carbons from carbonizing different MOFs and carbonization temperature on ORR have been systematically investigated. The nitrogen (N), phosphorus (P) and sulphur (S) ternary-doped metal-free porous carbon materials have been successfully synthesized using MOFs as templates (denoted as NPS-C-MOF-5) for oxygen reduction reaction (ORR) for the first time.