Comparison of methods to determine electrocatalysts’ surface area in gas diffusion electrode setups: a case study on Pt/C and PtRu/C

Abstract

In recent years, gas diffusion electrode half-cell setups have attained increasing attention bridging the gap between fundamental and applied fuel cell research. They allow quick and reliable evaluation of fuel cell catalyst layers and provide a unique possibility to screen different electrocatalysts at close to real experimental conditions. However, benchmarking electrocatalysts’ intrinsic activity and stability is impossible without knowing their electrochemical active surface area (ECSA). In this work, we compare and contrast three methods for the determination of the ECSA: (a) underpotential deposition of hydrogen (Hupd); (b) CO-stripping; and (c) underpotential deposition of copper (Cuupd) in acidic and alkaline electrolytes, using representative electrocatalysts for fuel cell applications (Pt and PtRu-alloys supported on carbon). We demonstrate that, while all methods can be used in gas diffusion electrode setups, CO-stripping is the most convenient and reliable. Additionally, the application of Cuupd offers the possibility to derive the atomic surface ratio in PtRu-alloy catalysts. By discussing the advantages of each method, we hope to guide future research in accurately determining surface area and, hence, the intrinsic performance of realistic catalyst layers.

Anchoring Ru nanoclusters to defect-rich polymeric carbon nitride as a bifunctional electrocatalyst for highly efficient overall water splitting

“…4f. The ESA CO of Ru NCs/V N -C 3 N 4 was calculated to be 979 cm 2 mg Ru −1 , much larger than those of Pd/RuO 2 –SnO 2 /C (690 cm 2 mg metal −1 ), 55 Pt 1 Ru 1.5 (780 cm 2 mg Ru −1 ) 56 and Pt 1 Ru 1 /Ir/C (975 cm 2 mg metal −1 ), 57 validating the larger surface area of the Ru NCs/V N -C 3 N 4 for the electrocatalytic reaction. 58 To eliminate the contributions of ECSA to the tested OER activity, the ECSA-normalized polarization curves were measured (Fig.…”

Lutetium-Induced Ultrafine PtRu Nanoclusters with a High Electrochemical Surface Area for Direct Methanol Fuel Cells at Alleviated Temperatures

“…The ECSAs were calculated from the COstripping because this method is more suitable for a Pt alloy. 40 The PtRuLu demonstrates an ultrahigh ECSA of 239.0 m 2 g Pt −1…”

“…These results indicate the significantly reduced CO absorption on the Pt sites in the case of PtRuLu. The ECSAs were calculated from the CO-stripping because this method is more suitable for a Pt alloy . The PtRuLu demonstrates an ultrahigh ECSA of 239.0 m 2 g Pt –1 , which is about 1.9 times and 2.5 times as high as PtRu (124.0 m 2 g Pt –1 ) and PtRu-JM (97.2 m 2 g Pt –1 ), respectively.…”

Accelerating materials research with a comprehensive data management tool: a case study on an electrochemical laboratory

“…Specifically, this can be the derivation of the ECSA from a CV by extracting the faradaic charge of a surface-specific reaction as illustrated in Fig. 4b, 63 or modeling a Nyquist plot by an equivalent circuit extracting inter alia the high frequency resistance (see Fig. S2†).…”