Catalytic performance of acid-treated multi-walled carbon nanotube-supported platinum catalyst for PEM fuel cells

Improved durability of Pt/CNT catalysts by the low temperature self-catalyzed reduction for the PEM fuel cells

“…The agglomeration of Pt was observed for all catalysts but the most significant one was Pt/C catalyst. The particle size of Pt/C increased by 215% but only by 124% in case of Pt/CNT-A, which is similar as previous report on fuel starvation operation [26]. On the other hand, Pt/ CNT-R showed only 19% increase in Pt size even after 6 h high voltage acceleration, which might also contribute to the less drop of cell performances, resistance and ECSAs in this study.…”

“…However, recent experiments showed that the electrocatalysts such as Pt or PteRu can accelerate carbon corrosion and reduce the corrosion potentials to 0.55 V (vs. RHE) or lower [37]. i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 7 ( 2 0 1 2 ) 1 7 9 9 2 e1 8 0 0 0 As previously reported in the fuel starvation condition [26], Pt/CNT-A showed less degradation after acceleration test due to its higher degree of graphitic crystallinity than Pt/C. The initial current density of MEA-1 and MEA-2 at 0.6 V were 795.7 and 771.3 mA cm À2 , respectively, which were reduced to 298.4 (À62.5%) and 499.0 mA cm À2 (À35.3%), respectively.…”

“…The acid treated catalyst (Pt/CNT-A) was i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 7 ( 2 0 1 2 ) 1 7 9 9 2 e1 8 0 0 0 synthesized using treated MWCNTs as catalyst supports via a polyol process described in our previous work [26]. The acid treated CNTs were separated from the solution and washed with deionized water.…”

“…[29,30]. The functional groups increased after acid treatment, which deteriorate the long-term durability of MEAs by the easy loss of carbon support and flooding phenomena as well as improve the dispersion of Pt particle and the bonding strength between Pt and carbon support [26]. The amount of functional group decreased in the entire species of functional groups after LTHB treatment, which may be due to dehydration by the atomic hydrogen transferred from Pt surface [27].…”

“…Recent studies showed that pre-treatment of CNTs with oxidizing chemicals could induce oxygen functional groups such as carboxyl (eCOOH), hydroxyl (eOH) and carbonyl (eCO) that are suitable for anchoring Pt metal onto the CNT, which resulted in the reduced size, improved distribution and enhanced electrocatalytic active area of Pt particles [22e25]. Meanwhile, recent study in our group showed that Pt catalysts supported on the highly functionalized CNT resulted in severe reduction of catalytic performances and loss of electrochemical surface area in the accelerated cell test due to the accelerated Pt agglomeration [26].…”