Effect of modification of multi-walled carbon nanotubes with nitrogen-containing polymers on the electrochemical performance of Pt/CNT catalysts in PEMFC

Abstract

The influence of the surface modification of multi-walled carbon nanotubes (MWCNT) with nitrogen-containing compounds on the performance of 40 wt% Pt/MWCNT catalysts in the oxygen electroreduction reaction (ORR) was investigated using a rotating disk electrode (RDE) at 10-35 °C in 0.1 M HClO 4 as electrolyte in electrochemical cell, and in a hydrogen-oxygen polymer electrolyte membrane fuel cell (PEMFC) at 82 °C. The catalysts were characterized by low-temperature nitrogen adsorption, XPS, TEM, gas-phase CO titration, electrooxidation of the adsorbed CO monolayer, and cyclic voltammetry. It was shown that the modification of MWCNT with melamine-formaldehyde resin leads to the surface nitrogen concentration up to 8.3 at.% (CNT-MF sample). The 40 wt% Pt/CNT-MF catalyst with 0.1 mg cm −2 Pt loading on the cathode showed a good performance in PEMFC (~ 0.61 W cm −2) and a high utilization ratio (0.84) of Pt in membrane electrode assembly as compared to Pt/CNT catalyst (~ 0.37 W cm −2 and utilization of 0.29). The higher power density of nitrogen-modified catalysts was ascribed to a higher utilization of Pt in the electrode layer.

The Advances in Biomedical Applications of Carbon Nanotubes

“…There are two main methods for the polymer modification: noncovalent attachment (polymer wrapping and absorption) and covalent attachment ("grafting") [37]. There is a range of studies on the effect of polymer modification on the electrochemical, mechanical, thermal, and rheological properties of CNTs [38][39][40][41]. In addition, polymer modification and hybridization with CNTs have been also actively studied with regard to bio-medical applications, particularly for bio-sensing [42][43][44].…”

Recent developments of nanocarbon based supports for PEMFCs electrocatalysts

“…In this way, N can be introduced into both carbon skeleton and carbon surface [113]. In the latter case, the already existing carbon materials are frequently treated in NH3 atmosphere, nitrogen plasma, melamine, polybenzimidazole, or ethylene diamine with carbonization to fix nitrogen on the carbon surface [110,112]. In this case, N was just introduced onto the carbon surface.…”

“…8(d)). Kuznetsov et al [112] prepared a Pt/MWCNT-MF catalyst using melamine-formaldehyde resin (MF) as nitrogen source to modify WMCNTs through nitrogen doping. The per-formance test results showed that the Pt/CNT-MF catalyst with a surface nitrogen content of 8.3 at% and a Pt loading of 0.1 wt% exhibited the best membrane electrode performance (0.61 W cm -2 ) and the highest Pt utilization coefficient (84%).…”

Green algae and gelatine derived nitrogen rich carbon as an outstanding competitor to Pt loaded carbon catalysts

“…The operational environment for Zn–air batteries is a neutral electrolyte or aqueous alkaline, increasing their environmental safety 1 , 5 , 6 . Platinum-based electrocatalysts are widely used due to their relatively low overvoltage and high current density 5 , 7 , 8 ; however, they have their disadvantages, such as no resistance to intermediates, slow kinetics, and instability with prolonged use 9 . Moreover, platinum-loaded electrode materials for anode design do not meet the cost and environmental requirements of the technologies of tomorrow.…”