Exploiting the Synergistic Electronic Interaction between Pt‐Skin Wrapped Intermetallic PtCo Nanoparticles and Co‐N‐C Support for Efficient ORR/EOR Electrocatalysis in a Direct Ethanol Fuel Cell

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202202071. The development of low-Pt catalysts with high activity and durability is critical for fuel cells. Here, Pt-skin wrapped sub-5 nm PtCo intermetallic nanoparticles are successfully mounted on single atom Co-N-C support by exploiting the barrier effect of Co-anchor. According to a collaborative experimental and computational investigation, the increased oxygen reduction reaction activity of PtCo/Co-N-C arises from the direct electron transfer from PtCo to Co-N-C, and the resulting optimal d-band center of Pt. Owing to such unique electronic structure interaction and synergistic effect, the specific and mass activities of PtCo/Co-N-C are up to 4.20 mA cm −2 and 2.71 A mg Pt −1 , respectively, with barely degraded stability after 40 000 CV cycles. The PtCo/ Co-N-C also exhibits outstanding activity as an ethanol electrocatalyst. This work shows a new and effective route to boost the overall efficiency of direct ethanol fuel cells in acidic media by integrating intermetallic low-Pt alloys and single atom carbon support.

Low-Loading Sub-3 nm PtCo Nanoparticles Supported on Co–N–C with Dual Effect for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells

“…The binding energy ( E b ) and the interlayer distance (DIS) between nanoparticles and Co–N–C carriers are calculated and presented in Figure c, corresponding to Pt/Co–N–C ( E b = 0.86 eV; DIS = 2.44 Å) and PtCo/Co–N–C ( E b = 1.76 eV; DIS = 2.04 Å). It is well illustrated in the previous literature that the higher binding energy and the smaller interlayer distance unveil the stronger interaction between nanoparticles and supports. , Thus, the above results demonstrate that the interaction between nanoparticles and supports is enhanced after forming PtCo intermetallic nanoparticles carried on Co–N–C, hence weakening the migration and aggregation of PtCo nanoparticles and increasing the stability of PtCo/Co–N–C. Besides, stronger interaction and shorter interlayer distance also facilitate charge transfer and H 2 O 2 migration from Co–N x sites to PtCo, improving the synergistic effect and accelerating the ORR kinetic rate .…”

“…There is a similar phenomenon when Pt is loaded on other M–N–C carriers. , Nevertheless, their activity and stability are still not satisfied with the demands for PEMFCs, which is attributed to the slight electron modulation on Pt nanoparticles from M–N–C supports and the dissolution of Pt during operation, respectively. It has been confirmed that Pt-based intermetallic catalysts possessed higher ORR activity and durability due to orderliness, compressive strain, and ligand effects in previous studies. ,,,− After alloying, the electronic structure of Pt was effectively regulated and the d-band center was changed significantly, which are conducive to enhancing the inherent activity of Pt-based catalysts. − Based on this, developing a catalyst through combining the ordered intermetallic compounds with M–N–C supports could achieve a significant enhancement for ORR and PEMFCs . However, Pt-alloy intermetallic compounds prepared by traditional methods showed a large particle size (around 5–10 nm), ,, which would reduce the Pt utilization and increase the oxygen mass transport resistance .…”

“…It has been confirmed that Pt-based intermetallic catalysts possessed higher ORR activity and durability due to orderliness, compressive strain, and ligand effects in previous studies. ,,,− After alloying, the electronic structure of Pt was effectively regulated and the d-band center was changed significantly, which are conducive to enhancing the inherent activity of Pt-based catalysts. − Based on this, developing a catalyst through combining the ordered intermetallic compounds with M–N–C supports could achieve a significant enhancement for ORR and PEMFCs . However, Pt-alloy intermetallic compounds prepared by traditional methods showed a large particle size (around 5–10 nm), ,, which would reduce the Pt utilization and increase the oxygen mass transport resistance . Besides, the separate method of synthesizing alloy nanoparticles and then loading them on M–N–C carriers resulted in weaker metal–support interaction and uncontrollable particle size .…”

“…36−39 Based on this, developing a catalyst through combining the ordered intermetallic compounds with M−N−C supports could achieve a significant enhancement for ORR and PEMFCs. 21 However, Pt-alloy intermetallic compounds prepared by traditional methods showed a large particle size (around 5−10 nm), 33,40,41 which would reduce the Pt utilization and increase the oxygen mass transport resistance. 42 Besides, the separate method of synthesizing alloy nanoparticles and then loading them on M−N−C carriers resulted in weaker metal−support interaction and uncontrollable particle size.…”

Electrocatalytic Oxidation of Urea and Ethanol on Two-Dimensional Amorphous Nickel Oxide Encapsulated on N-Doped Carbon Nanosheets

“…For example, Bu et al 60 reported that the synergistic interaction between the N-doped graphene and perovskite makes it a versatile electrocatalyst. Qiu and co-workers 61 reported the synergistic interaction between Pt-skin-wrapped intermetallic PtCo nanoparticles and Co−N−C support boosts the ORR/EOR performances in direct ethanol fuel cells. Therefore, the synergistic interaction between the CN x support and NiO x could boost the activity of the catalyst.…”