Uniform Distribution of Ruthenium Nanoparticles on Nitrogen-Doped Carbon Nanostructure for Oxygen Reduction Reaction

Abstract

Highly efficient, durable, and economically viable electrocatalysts for oxygen reduction reaction (ORR) is central for energy conversion and storage devices such as fuel cells and metal–air batteries. Despite of the enormous recent achievements, it is challenging to achieve satisfactory activity and stability at the same time due to lack of fundamental understanding on the activity governing factors. Here, we demonstrate the mechanistic insight of oxygen reduction on the uniformly dispersed Ru nanoparticles on N-doped carbon support (Ru@NC). The promotion of energy efficient inner-sphere electron transfer mechanism with reduced HO2 – generation demonstrates as the crucial descriptor for appreciable activity and remarkable stability. In terms of the mass activity, the developed catalyst outperforms other previously reported state-of-the-art catalysts. The greatly suppressed HO2 – generation endows remarkable stability (∼6 mV of negative shift in half-wave potential and only 1.9% reduction of activity at 0.9 V after 10000 potential cycles) in alkaline medium. Overall, Ru@NC exhibits remarkably superior stability which is much better than the limit fixed by the U.S. Department of Energy (DOE) and surpasses the state-of-the-art Pt/C catalyst.

Self-Assembled TMD Nanoparticles on N-Doped Carbon Nanostructures for Oxygen Reduction Reaction and Electrochemical Oxygen Sensing Thereof

“…Thus, a very small or no such hump within the 0.6−0.9 V range is observed for WS 2 /N x C_50 (Figure 6c), signifying direct interaction between the electroactive centers and the dissolved oxygen molecule promoting the ISET process (as shown in Figure 6a) and thus sequential/direct 4e − transfer. 66,67 Moreover, the peak at ∼0.4 V is attributed to the promotion of OSET by carbon supports, which is more prominent in the case of Pt/C. Comparatively, a very small hump-like structure around ∼0.4 V due to the widening of the ring current can be assigned to the possible OSET process in the case of WS 2 / N x C_50 that is facilitated by some oxygen functionalities present in carbon.…”

Recent Development and Future Frontiers of Oxygen Reduction Reaction in Neutral Media and Seawater

“…Ruthenium (Ru) and rhodium (Rh), other noble-metal counterparts, hold promise as a compelling alternative to Pt in serving as an electrocatalyst for the ORR, in the virtue of their comparative affordability and higher methanol tolerance. [72,73,92,93] However, their utilization as an ORR catalyst in neutral media, as well as in acid or basic media, has been relatively scarce, predominantly attributed to their intrinsic properties. Reports have consistently shown that Ru-based catalysts, particularly RuO 2 , exhibit sluggish ORR kinetics, resulting in lower ORR current and higher overpotential compared to Pt.…”

Advances in platinum-based and platinum-free oxygen reduction reaction catalysts for cathodes in direct methanol fuel cells

“… Bisen and Nanda (2021) synthesized a Ru nanoparticle-loaded carbon structure for ORR. The illustration for the synthesis is shown in Figure 9A .…”

“… (A) Illustration of the synthesis route; (B) activity of the as-synthesized catalyst for different cycles of tests; and (C) the stability comparison of Ru@NC_800 and commercial Pt/C. Reproduced with permission ( Bisen and Nanda, 2021 ). Copyright 2021, American Chemical Society.…”