Combinatorial Search for Quaternary Methanol Tolerant Oxygen Electro‐Reduction Catalyst

Abstract

A combinatorial library containing 645 different compositions was synthesised and characterised for methanol tolerant oxygen electro‐reduction reaction (ORR) catalytic performance. The library was composed of compositions involving between 1 and 4 metals among Pt, Ru, Fe, Mo and Se. In an optical screening test, Pt(50)Ru(10)Fe(20)Se(10) composition exhibited the highest ORR activity in the presence of methanol. This composition was further investigated by synthesis and characterisation of a powder version catalyst [Pt(50)Ru(10)Fe(20)Se(10)/C]. At 0.85 V [vs. reversible hydrogen electrode (RHE)] in the absence of methanol, the Pt/C catalyst exhibited higher ORR current (0.0990 mA) than the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst (0.0902 mA). But much higher specific activity (12.7 μA cmpt–2) was observed in the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst than for the Pt/C catalyst 6.51 μA cmpt–2). In the presence of methanol, the ORR current decreased by 0.0343 and 0.247 mA for the Pt(50)Ru(10)Fe(20)Se(10)/C and Pt/C catalysts, respectively, which proved the excellent methanol tolerance of the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst.

Combinatorial search for oxygen reduction reaction electrocatalysts: A review

“…Although fluorescein can operate at a higher pH range than Phloxine B, it should be mentioned that NaNO 3 was added to the electrolyte solution in the case of Refs. [39,40] to maintain conductivity of the electrolyte. Operating at a higher pH brings an advantage of easy detection of activity because far less amount of proton consumption is required at higher pH range, which means fluorescein is more sensitive to the proton consumption.…”

“…In the Pt-based array, PteBi and PteSe binary compositions exhibited high ORR activities, while RuFe did in the non-Pt array. The identical condition was employed by Jeon et al [40] to search for methanol tolerant ORR electrocatalysts. In this study, the best composition Pt(50)Ru (20) Fe (20)Se (10) was also investigated in its powder version, which also exhibited excellent methanol tolerance.…”

Combinatorial High-Throughput Optical Screening of High Performance Pd Alloy Cathode for Hybrid Li–Air Battery

“…The prepared combinatorial library was used as a working electrode in the analysis of optical screening. 29 Optical screening requires an electrolyte with the properties of a UV sensitive pH indicator. From previous reports, fluorescein Na salt was used as the pH indicator to investigate the ORR performance of the catalyst spots in combinatorial library.…”

“…29,30,32−40 In our group, this methodology was used to investigate various optimized catalysts in the field of fuel cells. 22,[29][30][31]41 However, this experiment was targeted to hybrid Li−air battery, therefore, the entire combinatorial system was…”

Fluorophore Metal–Organic Complexes: High-Throughput Optical Screening for Aprotic Electrochemical Systems

“…Optical methods, favored for their ease and speed, rely on the performance of the fluorophore indicators for which ultraviolet (UV) sensitivity is triggered by a change in pH of the electrolyte. ,− These dyes have enabled the rapid screening of electrocatalysts for many H + -involved processes such as oxygen reduction/evolution reactions (ORR/OER, O 2 + 4H + + 4e – ↔ 2H 2 O) − and methanol oxidation (CH 3 OH + H 2 O → CO 2 + 6H + + 6e – ). ,− This type of optical screening technology, requiring the ready availability and transfer of protons, is difficult to apply to nonaqueous electrolytes.…”