Strong Interaction between Platinum Nanoparticles and Tantalum-Doped Tin Oxide Nanofibers and Its Activation and Stabilization Effects for Oxygen Reduction Reaction

Abstract

Electrocatalyst supports stable to high potential are required for the proton exchange membrane fuel cell cathode. Electrocatalyst supports based on tantalum doped tin oxide (Ta: SnO2) were prepared by electrospinning. The dopant amount was varied between 0 (undoped SnO2, TO) and 7.5 at.%, and the resulting materials were characterized for their morphology, composition, structure, porosity and electrical properties. Platinum nanoparticles prepared by a microwave assisted polyol method were deposited with different loadings on 1 at.% Ta doped SnO2 (1Ta:SnO2), selected for its highest electrical conductivity of 0.09 S cm -1 . Their electrocatalytic properties towards the oxygen reduction reaction (ORR) were compared with those of the same S2 particles deposited on carbon black and those of a commercial carbon supported Pt catalyst.Pt/1Ta:SnO2 showed higher ORR activity and stability at high potential than Pt/C. In particular, the electrocatalyst with the lowest Pt loading (7 wt%) presented high mass activity and stability which, from XPS analysis, is suggested to result from very strong metal support interaction. These results indicate that amongst tin oxides doped with pentavalent metals such as niobium (Nb:SnO2), antimony (Sb:SnO2) and tantalum, Ta:SnO2 has the advantage of both higher conductivity than Nb:SnO2, and greater stability in the fuel cell voltage range than Sb:SnO2.

Oxygen Reduction Reaction Promoted by the Strong Coupling of MoS2 and SnS

“…The XPS survey spectrum of MoS 2 -SnS/NPC (Figure S3) shows the existence of Mo, Sn, S, N, C, and O. The high-resolution Sn 3d spectra (Figure a) reveal the presence of Sn 3d 3/2 (494.93 eV) and Sn 3d 5/2 (486.47 eV). , For Mo 3d spectra (Figure b), two peaks of Mo 3d 3/2 and Mo 3d 5/2 are observed at 232.42 and 229.17 eV, respectively. Moreover, S 2s (226.34 eV) and Mo 6+ (235.98 eV) can be detected. ,, The presence of little Mo 6+ is the result of air oxidation.…”

Eriobotrya japonica assisted green synthesis of g‐C3N4 nanocomposites and its exceptional photoactivities for doxycycline and rhodamine B degradation with mechanism insight

“…It has promising applications in the fields of transparent conducting electrodes, transistors, antistatic films, rechargeable lithium batteries, and devices, because of its easy synthesis processes, good reversibility, and low manufacturing costs. [30] For understanding, Figure S4 shows the comprehensive synthesis scheme for SnO 2 nanosheets coupled green g-C 3 N 4 nanosheets nanocomposite through a sequential template approach. While the XRD pattern and TEM image of SnO 2 nanosheets are shown in Figure S5A,B respectively.…”

Platinum Nanocatalysts Supported on Defective Hollow Carbon Spheres: Oxygen Reduction Reaction Durability Studies

“…Currently, the state-of-the-art PEMFC catalyst is a Pt or a Pt/transition metal bimetallic catalyst placed on a variety of supports. Supports that have been used vary from structured carbons like nanotubes (CNTs), nanofibers (CNFs), carbon black (CB), broken hemispherical hollow carbons (BHCSs) as well as doped metal oxides and carbides ( Mao et al, 2019 ; Jiménez-Morales et al, 2020 ; Mohideen et al, 2020 ; Wang et al, 2020 ; Mashindi et al, 2021 ). Carbon supports are favoured due to their different structured forms, their lightweight that is important for mobile applications, thermal stability for high-temperature applications, high surface area for nanoparticle deposition and gas diffusion, as well as their earth abundance.…”

“…The long-term goal is thus to develop a highly durable catalyst that is cheap and can sustain operation over 5,000 h as proposed by the United States Department of Energy in its fuel cell blueprint ( Ren et al, 2020 ). Though newer non-carbon supports for Pt have been discovered in the previous decade, the other favorable properties of structured carbons have made it difficult to completely dispose of carbon as the support of choice, hence the continuous study on how a structured carbon can enhance the durability of the fuel cell catalysts ( Jackson et al, 2017 ; Mohamed et al, 2018 ; Jiménez-Morales et al, 2020 ). Even though a few studies have been conducted on Pt supported on hollow carbon spheres (HCSs) and nitrogen doped HCSs (NHCSs), detailed studies on durability protocols have not been comprehensively elucidated for these catalyst systems.…”