N‐rich mesoporous carbon supported CoNC and FeNC catalysts derived from o‐phenylenediamine for oxygen reduction reaction

Abstract

The exploitation of high efficiency non-precious electrocatalysts for oxygen reduction reaction (ORR) is of great significance for large-scale commercialization of next-generation fuel cells. Herein, we report the synthesis of conjugated polymers (CP) based on poly(o-phenylenediamine) as a nitrogen-containing precursor for preparation of Co-and FeCl 3 -doped N-rich carbon for ORR (abbreviated as Co-OPD and FeCl 3 -OPD). Based on their high specific surface, excellent porosity and large pyridine nitrogen content, the as-synthesized FeCl 3 -OPD, which is prepared at a pyrolysis temperature of 800 C (FeCl 3 -OPD-800), exhibits highest catalytic activity among the resulting electrocatalysts, that is, it possesses a largest half-wave potential of 0.854 V (≈20 mV more positive than Pt/C), a high diffusion limiting current density of 3.95 mA cm −2 and a biased 4e − reaction pathway. In addition, this catalyst also discloses an excellent methanol tolerance and better durability than the commercial Pt/C. Taking advantage of their high ORR activity as well as simple fabrication which makes it possible using inexpensive FeCl 3 as both catalysts for CP precursors and metal dopant for FeCl 3 -OPD only by a one-step pyrolysis, thus such FeCl 3 -OPD may hold great potentials as promising alternative of precious metal catalysts for next generation fuel cells.

Boosting the Oxygen Reduction Reaction in Zn–Air Batteries via a Uniform Trace N-Doped Carbon-Based Pore Structure

“…The intensity ratio (I D /I G ) reflects the defect concentration of carbon. 30 The I D /I G ratios of the SPC (1.05) and USPC (1.07) were higher than that of PC (1.03) and UPC (1.05), respectively, demonstrating that NaCl activation caused structural defects. 27 PC with the lowest I D /I G ratio (1.03) exhibited the worst performance.…”

“…The G-band at ∼1586 cm –2 could be attributed to the vibration of the E 2g vibration mode (including C–C and C–N bonds) in sp 2 -bonded graphite carbon. The intensity ratio ( I D / I G ) reflects the defect concentration of carbon . The I D / I G ratios of the SPC (1.05) and USPC (1.07) were higher than that of PC (1.03) and UPC (1.05), respectively, demonstrating that NaCl activation caused structural defects .…”

“…However, these are not sufficient to meet the requirements for ORR activity. − The introduction of N atoms larger than C into MOFs may cause a higher strain at their edges, thus promoting the charge potential and chemical adsorption of oxygen, which are the main reasons for the enhanced ORR activity. − Many reports have confirmed that N doping, mostly in the form of pyridine nitrogen and graphite nitrogen, can effectively improve the ORR activity of catalysts. ,− It is widely acknowledged that urea is the most popular nitrogen source due to its low cost and high content of nitrogen. More importantly, urea is more likely to synthesize the catalytic sites such as pyridine nitrogen and graphite nitrogen during the process of high-temperature pyrolysis. ,− …”

Mesoporous carbon-based materials and their applications as non-precious metal electrocatalysts in the oxygen reduction reaction

“…Eq. ( 8) The performance of electrocatalysts in the ORR is normally assessed using electrochemical techniques, such as cyclic voltammetry, linear sweep voltammetry and rotating disc electrode (RDE) experiments [77,78,81]. As illustrated in Fig.…”

“…Therefore, there is increasing interest in the development of more sustainable ORR electrocatalysts from Earth abundant elements that are cost-effective and readily scalable. It is no surprise that carbon-based materials, including MC and OMC are attracting considerable interest in the development of ORR electrocatalysts, as they are environmentally acceptable, inexpensive with very good stability and are readily available [81,82].…”