Rutile Ti_0.9Ir_0.1O₂‐Supported Low Pt Loading: An Efficient Electrocatalyst for Ethanol Electrochemical Oxidation in Acidic Media

Abstract

Developing a cost‐effective electrocatalyst toward ethanol electrochemical oxidation plays a vital role in large‐scale applications of direct ethanol fuel cells (DEFCs). Herein, a rutile Ti0.9Ir0.1O2‐supported low Pt‐loading catalyst is fabricated using a surfactant‐free one‐pot chemical reduction route at room temperature that not only reduces the amount of the Pt loading but also significantly enhances the CO antipoisoning and electrochemical stability toward ethanol electrochemical oxidation compared with the conventional carbon‐supported Pt electrocatalyst. The rutile Ti0.9Ir0.1O2 nanosupport with rod‐like morphology is first prepared via a one‐pot hydrothermal route, and then 15.5 wt% Pt nanoparticles with small size (≈3 nm) are anchored on it by the surfactant‐free chemical reduction process. For ethanol electrochemical oxidation, the rutile Ti0.9Ir0.1O2‐supported Pt catalyst shows a moderate current density (≈13.74 mA cm−2), which is comparable with the 20 wt% Pt/C electrocatalyst, despite its low loading (15.5 wt%). In addition, the rutile Ti0.9Ir0.1O2‐supported low Pt‐loading electrocatalyst demonstrates low onset potential (0.45 V vs normal hydrogen electrode [NHE]), superior CO‐tolerance, and impressive electrochemical stability compared with the carbon‐supported Pt catalyst. These enhancements are ascribable to the inherent durability of the rutile TiO2 nanostructure and the synergistic effect between Pt and Ti0.9Ir0.1O2 nanosupport.

Enhanced formic acid electro-oxidation reaction over Ir,N-doped TiO2-supported Pt nanocatalyst

“…Additionally, the location of the diffraction peaks in the XRD pattern of the Ir,N-doped TiO 2 was slightly shifted to a more positive 2θ angle than the standard TiO 2 structures, being assigned to the different ionic radius of Ti 4+ (0.605 Å) and Ir 4+ (0.625 Å) when introducing Ir element into the TiO 2 structure [9,38,39]. Furthermore, N 3− ions (0.14 Å) can replace O 2− ions (0.13 Å) in the TiO 2 lattice, resulting in the similar length of the Ti-N and Ti-O bond (2.081 Å and 2.002 Å, respectively) [40].…”

“…Although titanium dioxide (TiO 2 ) has been considered a co-catalyst to increase the catalytic activity and CO-tolerance ability of Pt NPs owing to their cation-exchange capacity, the very poor electrical conductivity dragged it out the electrochemical applications [2,[8][9][10]. An efficient strategy for addressing this issue is to incorporate other elements into the TiO 2 lattice, for instance, cationic doping can enhance the electrical conductivity by the formation of the 'aliovalent-ion' effect in the TiO 2 structure [11][12][13][14][15].…”

Milestones of Electrocatalyst Development for Direct Alcohol Fuel Cells

“…[12,14b] In recent years, ethanol has gained attention as a potential fuel to substitute methanol because it is easily generated from biomass, is nontoxic, and has high energy density. [15] The pioneering study on the ethanol oxidation reaction (EOR) mechanism was reported in the 1950s and now has evolved into a dual-pathway mechanism, consisting of C 1 and C 2 pathways. In the C 1 mechanism, the ethanol is completely oxidized to CO 2 through the cleavage of the C─C bond and multiple dehydrogenation and oxidation steps that can release 12 electrons on each ethanol molecule; however, this process is not easy for the fuel cells operation at moderate temperature (≤ 100 °C).…”

Synthesis and characterization of Ti0.9Ir0.1O2-activated carbon composite as a promising support for catalysts in electrochemical energy conversion

“…Therefore, designing robust support is necessary for the next-generation development of renewable and sustainable energy-related conversion technologies. Recently, our group successfully fabricated Ir-doped TiO 2 material via a green hydrothermal method that served as efficient catalyst support for Pt nanoparticles (NPs) for the alcohol electro-oxidation process [16,17]. The Pt NPs/Irdoped TiO 2 catalyst exhibited high CO-tolerance and great electrochemical durability compared to the commercially available C-supported Pt (NPs) catalyst, which was attributable to the synergistic effects and SMSI between Ir-doped TiO 2 and Pt NPs.…”

“…NPs. In a typical experiment, IrCl 3 .xH 2 O was dissolved into 50 ml of distilled water, followed by adjusting pH to 0 by HCl. Next, TiCl 4 was added to the above solution and then transported into a Teflon-lined autoclave, being heated to 210 °C for 12 h. Finally, the resultant product was centrifugated and then dried for further use [16,17,24].…”