Pt‐Nanoparticle‐Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Abstract

this corrosion, including the use of sp 2carbon materials without functional groups, i.e., carbon nanotubes [11] and graphene, [12] and noncarbon materials [13] as nanoparticle supports and the decoration of the Pt nanoparticles on carbon. [14] Although these approaches have been effective in reducing the degradation to varying degrees, unfortunately, further developments are required due to the high costs, complex preparation procedures, and insufficient electrode performances resulting from these approaches. Hence, developing an effective approach to provide high electrocatalytic activity and catalyst stability is a great challenge.An ionic liquid (IL) is a liquid salt consisting of a cation and anion at room temperature and is a subset of a molten salt. The unique features of an IL, such as a negligible vapor pressure, wide electrochemical window, good thermal stability, antistatic properties, have led to many proposed applications thus far. Recently, we reported Pt-nanoparticle-supported carbon electrocatalysts easily produced by agitating Pt-nanoparticle-monodispersed ILs, which were prepared by magnetron sputtering onto the ILs, [15,16] with various carbon supports, e.g., carbon nanotubes and carbon black, under heating conditions. [17][18][19][20][21][22] The resulting electrocatalysts showed favorable catalytic activities for ORR and high durabilities. [23] The latter feature was attributed to the thin IL layer between the Pt nanoparticles and carbon support, which suppressed carbon corrosion. [23] ILs should play key roles in the further improvement of electrocatalysts. Here, we focused on a protic organic salt (POS) and protic ionic liquid (PIL) that are easily synthesized, a cost-effective option and often show desirable physicochemical properties over commonly used ILs. [24][25][26][27] To reveal the effects of the ILs on the catalytic activities of the resulting Pt-nanoparticle-supported carbon materials, diphenylammonium hydrogen sulfate ([DPA][HSO 4 ]) and N,N-diethyl-N-methylammonium hydrogen sulfate ([DEMA] [HSO 4 ]) were exploited in this investigation as a POS and a PIL, respectively. The aim of this study is to disclose approaches to improve the performances of electrocatalysts for PEFCs.[DPA] [HSO 4 ] and [DEMA] [HSO 4 ] were prepared by procedures described in previous articles. [26,27] [DEMA] [HSO 4 ] was used in a sputtering process to produce a Pt-nanoparticlemonodispersed IL.[DPA] [HSO 4 ], which is a solid salt at room temperature, was used as an additive to provide functionality to the Pt-nanoparticle-supported carbon materials. In this article, electrocatalysts prepared with and without [DPA][HSO 4 ] Pt-nanoparticle-supported carbon catalysts for the electrochemical oxygen reduction reaction produced using a Pt-nanoparticle-monodispersed ionic liquid (IL) show better durability than a commercially available catalyst due to the small amount of IL between the Pt nanoparticles and the carbon support. In this study, to add further functionality to the catalysts prepared with the Pt-na...

Room-Temperature Fabrication of Electrocatalyst for Oxygen Reduction Using Pt Nanoparticle-dispersed Protic Ionic Liquid with Poly(3,4-ethylenedioxythiophene)

“…We have previously reported enhancement of catalytic activitie by adding electropolymerizable compounds like aniline and diphenyl amine in Ptsputtered IL, as mentioned in the introduction section. 7,8 Compared to the polymers of those compounds, PEDOT possesses the highest To estimate optimized amount of EDOT in the Pt-sputtered PIL, the mass activities of Pt-NPs/PIL+EDOT/C containing different amount of EDOT were measured and the obtained values are plotted as a function of EDOT concentration, as shown in Fig. 3(b).…”

“…As a deliberate method to solve this problem, we added an electropolymerizable compound in the IL and a conducting polymer network is formed in the IL layer by electrochemical oxidation. 7,8 This strategy effectively works when using diphenyl amine and aniline as additives, but use of some other additives regrettably resulted in a failure; pyrrole and 3,4-ethylenedioxythiophene were decomposed when heated to induce Pt-NPs adsorption. Poly(3,4-ethylenedioxythiophene) (PEDOT) prepared by oxidative polymerization of the latter compound is known well as one of the ideal conducting polymers due to its attractive properties like high conductivity (up to 300 S cm ¹1 ), high environmental stability, and flexibility, especially, when composited with poly(styrenesulfonate).…”

Ionic liquid‐modified materials as polymer electrolyte membrane and electrocatalyst in fuel cell application: An update

“…In Izumi et al's study, 173 This is due to developing a (poly(diphenylamine)) conducting polymer among Pt nanoparticles and carbon support through possible processing. Li et al 174,175 described a processing technique that helps in the development of a thin (<2 nm) conformal IL covering the layer of threedimensional electrocatalysts and bulk single crystals by sequential capacitive deposition (SCD) of anionic and cationic components and their subsequent condensation into a hydrophobic, protic IL.…”

Recent Advances in Layered-Double-Hydroxides Based Noble Metal Nanoparticles Efficient Electrocatalysts

“…Unfortunately, it is still a difficult and challenging problem to improve the utilization rate of active components, the rate of catalytic reaction and the thermal stability of the catalyst by controlling the dispersion of active sites and the microstructure [22]. Loading the catalyst on suitable supporters (such as carbon materials [23][24][25], metals [26,27], metal oxide [28,29], metal hydroxide [30,31], metal-organic frameworks [32][33][34] and boron nitride [35,36]) is an optimal strategy to solve this problem. In particular, layered double hydroxides (LDHs) and their derivatives (metal hydroxides, hydroxides, oxides, sulfides, nitrides and phosphides) are widely studied in water splitting, due to their compatible properties with traditional noble metals, easy synthesis, low cost, rich resources, good activity and long-time durability [37,38].…”