Degradation Analysis of Pt/Nb–Ti<sub>4</sub>O<sub>7</sub> as PEFC Cathode Catalysts with Controlled Arc Plasma-deposited Platinum Content - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Electrochemistry (Tokyo, Japan) Année : 2022

Degradation Analysis of Pt/Nb–Ti4O7 as PEFC Cathode Catalysts with Controlled Arc Plasma-deposited Platinum Content

Résumé

For polymer electrolyte fuel cell cathodes, highly durable supports are required to prevent catalyst degradation in supports. In this study, as model Pt catalysts, 2-10 wt% Pt was deposited on Magneli-phase niobium-doped macroporous Ti4O7 (Nb-Ti4O7) mounted on glassy carbon rods using the coaxial arc plasma deposition method. The morphologies of 2, 5, and 10 wt% Pt catalysts showed the hemisphere fine particles, islands with ca. 1.4nm diameter and ca. 2.4nm thickness, and films with ca. 3.3nm thickness, respectively. During start/stop accelerated durability tests (ADTs) of 5000 cycles following the Fuel Cell Commercialization Conference of Japan protocol, Pt was slightly agglomerated; consequently, the morphologies of the 2, 5, and 10 wt% Pt catalysts were island-like with 3.5nm thickness, chain bead-like with 4 nm thickness, and film-like with 4 nm thickness, respectively. This slight agglomeration led to good durability during the ADTs. Herein, the oxygen reduction reaction (ORR) mass activity (MA) values at 0.9 V vs. reversible hydrogen electrode (RHE) of the 2, 5, and 10 wt% Pt catalysts were 79, 60, and 36 Ag-pt(-1) after 5000 cycles ADT, respectively, which had declining ratios after 5000 cycles were 32 %, 17 %, and 0%, respectively. The island-like and film-like Pt/Nb-Ti4O7 presented activity and durability comparable to a Pt/C catalyst, which was 42 A(Pt)(g-1) (0.9 V vs. RHE) with a 12% of declining ratio after the ADTs. The durability of the MA suggested that the different affinity caused by different crystal faces led to the slight agglomeration of 2, 5, and 10 wt%_Pt/Nb-Ti4O7 catalysts. These catalysts showed electrochemical surface areas (ECSAs) of 36, 27, and 29m(2) g(-1) after the ADTs, with declining ratios as low as 20 %, 6%, and 0%, respectively. All Pt/Nb-Ti4O7 catalysts showed higher durability of the ECSAs than the Pt/C catalyst, which was 68m(2) g(-1) with a 30% declining ratio after the ADT. Different from common Pt nanoparticle catalysts, which agglomerate into large spherical Pt particles, the slight agglomeration was caused by the interconnection of the deposits and supplemented by a limited increase in the diameter or thickness. The island-like morphology of Pt with a limited thickness presented both high durability and activity among the Pt/Oxide catalysts.
Fichier principal
Vignette du fichier
90_22-00025_Ma-Shige2.pdf (3.7 Mo) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03866669 , version 1 (22-11-2022)

Identifiants

Citer

Yongbing Ma, Hirokata Kajima, Yuta Shimasaki, Takaaki Nagai, Teko W Napporn, et al.. Degradation Analysis of Pt/Nb–Ti4O7 as PEFC Cathode Catalysts with Controlled Arc Plasma-deposited Platinum Content. Electrochemistry (Tokyo, Japan), 2022, 90 (5), pp.057004-057004. ⟨10.5796/electrochemistry.22-00025⟩. ⟨hal-03866669⟩
6 Consultations
19 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More