Pt_0.25Ru_0.75/N‐C as Highly Active and Durable Electrocatalysts toward Alkaline Hydrogen Oxidation Reaction

Abstract

A series of uniform 3.0–3.8 nm Pt1−xRux particles supported on nitrogen‐doped carbon (N‐C) is synthesized by wet‐impregnation, high‐temperature reduction, and high‐temperature NH3 etching. As far as it is known, the resultant Pt0.25Ru0.75/N‐C exhibits the highest activity toward alkaline hydrogen oxidation reaction (HOR) in terms of mass specific exchange current density (j0,m, 1654 A gPtRu−1), that is 4.7 and 1.4 times of commercial Pt/C (352 A gPt−1) and PtRu/C (1213 A gPtRu−1), respectively. The remarkable activity originates from a high electrochemical active surface area (ECSA), weakened hydrogen binding energy (HBE), and appropriate oxophilic property. Additionally, the Pt0.25Ru0.75/N‐C displays much improved durability during potential cycling with respect to commercial Pt/C and commercial PtRu/C, likely arising from the stabilizing effect of nitrogen dopant of N‐C on Pt0.25Ru0.75. Furthermore, the single cell fabricated with 0.08 mgPt cm−2 of the Pt0.25Ru0.75/N‐C as the anode reaches a peak power density of 831 mW cm−2, which is 1.8 and 1.1 times of that fabricated with 0.2 mgPt cm−2 of commercial Pt/C and 0.13 mgPt cm−2 of commercial PtRu/C as the anode, respectively. This study exhibits that low‐platinum alkaline HOR electrocatalyst should be a highly promising approach for hydroxide exchange membrane fuel cells (HEMFCs).

Electrocatalytic Hydrogen Oxidation in Alkaline Media: From Mechanistic Insights to Catalyst Design

“…The Ru-segregated PtRu demonstrated the highest activity, superior to other Pt and PtRu alloy counterparts (Figure b), which was ascribed to the surface oxophilicity and weaker HBE (reflected by the lower H UPD peak potential, Figure c). A similar Pt 0.25 Ru 0.75 /N–C catalyst with Ru clusters segregated on the surface was reported by Cong et al . In the same vein, the enhancement of HOR activity was also observed in Ru/Pd 3 Ru by Qin et al .…”

“…Cong et al . investigated the synergistic effect of hydrogen affinity and oxophilicity on the HOR activity in PtRu alloys through CV and CO stripping tests . Thereafter, in the experiment conducted by Alia et al ., a 5% Cu monolayer on the Pt electrode was proved to significantly enhance the HOR activity .…”

Synergistic Electrocatalysts for Alkaline Hydrogen Oxidation and Evolution Reactions

“…Song et al also reported a Pt 0.25 Ru 0.75 /N-C alloy comprising Pt-Ru alloy and surface segregated Ru clusters exhibited excellent mass-specific HOR activity, superior to commercial Pt/C and Pt-Ru/C counterparts. [74] The surface Ru, probably resulting from the annealing process in Ar, endowed Pt 0.25 Ru 0.75 /N-C with appropriate oxophilicity. Notably, the incorporation of Ru also weakened the HBE of Pt due to the electron transfer from Pt to Ru.…”

Nano-Sized PtRu/C Electrocatalyst With Separated Phases and High Dispersion Improves Electrochemical Performance of Hydrogen Oxidation Reaction

“…Then Ru@Pt core-shell catalysts were synthesized on glassy carbon by UPD-GD approach ( Xing et al, 2020 ). Cong et al synthesized a series of uniform 3.0–3.8 nm Pt1−xRux particles supported on nitrogen-doped carbon (N-C) by wet-impregnation, high-temperature reduction, and high-temperature NH3 etching ( Cong et al, 2020 ). However, the aforementioned catalysts have complex structure and preparation process, and the use of strong reducing agents such as NaBH4 will cause harm to human health.…”