Phase Segregated Pt–SnO₂/C Nanohybrids for Highly Efficient Oxygen Reduction Electrocatalysis

Abstract

Strengthening the interfacial interaction in heterogeneous catalysts can lead to a dramatic improvement in their performance and allow the use of smaller amounts of active noble metal, thus decreasing the cost without compromising their activity. In this work, a facile phase‐segregation method is demonstrated for synthesizing platinum–tin oxide hybrids supported on carbon black (PtSnO2/C) in situ by air annealing PtSn alloy nanoparticles on carbon black. Compared with a control sample formed by preloading SnO2 on carbon support followed by deposition of Pt nanoparticles, the phase‐segregation‐derived PtSnO2/C exhibits a more strongly coupled PtSnO2 interface with lattice overlap of Pt (111) and SnO2 (200), along with enhanced electron transfer from SnO2 to Pt. Furthermore, the PtSnO2 active sites show a strong ability to degrade reactive oxygen species. As a result, the PtSnO2/C nanohybrids exhibit both excellent activity and stability as a catalyst for the oxygen reduction reaction, with an overall performance which is superior to both the control sample and commercial Pt/C catalyst. This phase‐segregation method can be expected to be applicable in the preparation of other strongly coupled nanohybrids and offers a new route to high‐performance heterogeneous catalysts for low‐cost energy conversion devices.

Equilibrated PtIr/IrOx Atomic Heterojunctions on Ultrafine 1D Nanowires Enable Superior Dual‐Electrocatalysis for Overall Water Splitting

“…[ 31,32 ] With respect to the O 1 s (Figure 2c), the binding energies of 534.0 and 532.5 eV typically assigned to hydroxyl species and adsorbed oxygen‐containing species. [ 33 ] Moreover, an additional peak around 531.0 eV, [ 34 ] which is ignorable on the pure Pt NWs, can be distinctly observed and assigned to lattice oxygen bonded to metal (Ir–O) on the samples of Ir/C, PtIr/IrO x ‐30 NWs, and PtIr/IrO x ‐50 NWs, further confirming the favorable in situ oxidation of Ir on the ultrafine NWs. When normalized by the Pt 4f, the relative intensity of Ir and Ir 4+ 4f for all the NWs represent a gradual upward trend with Ir content increases (Figure S8, Supporting Information), firmly suggesting the evolutionary surface feature of regulable Pt/IrO x AHJs as schematically shown by Figure 2e.…”

“…[31,32] With respect to the O 1s (Figure 2c), the binding energies of 534.0 and 532.5 eV typically assigned to hydroxyl species and adsorbed oxygen-containing species. [33] Moreover, an additional peak around 531.0 eV, [34] which is ignorable on the pure Pt NWs, can be distinctly observed and assigned to lattice show an inverted volcanic trend, of which PtIr/IrO x -30 NWs/C reaches the lowest value (20 mV) (Figure S11a, Supporting Information). In addition, the PtIr/IrO x -30 NWs/C presents the gentlest Tafel plots (38 mV dec −1 ) among all electrocatalysts (Figure 3b), reflecting the fastest HER reaction kinetics and a potential Volmer-Heyrovsky process.…”

Tuning d‐Band Center of Pt by PtCo‐PtSn Heterostructure for Enhanced Oxygen Reduction Reaction Performance

“…[31][32][33][34][35] Therefore, improving the electrochemical catalytic activity/stability of Pt-based catalysts is critical to PEMFCs. [36][37][38][39] Many strategies have attempted to boost the stability and activity of Pt binary alloy, such as core shell, [40] dope, [41][42][43][44] interface engineering, [45,46] etc. Interface engineering has been considered as an effective approach for designing highly active ORR catalysts, which can promote the electron transfer and regulate the adsorption/desorption energies of active species during the reaction process, thus improving the ORR performance.…”

Highly Dispersed Pt Clusters on F-Doped Tin(IV) Oxide Aerogel Matrix: An Ultra-Robust Hybrid Catalyst for Enhanced Hydrogen Evolution

“…A tiny peak shift in the Pt 4f core-level XPS spectrum is evidence of the electronic modification of the Pt 5d band by either charge transfer or alloy formation with the support. 72,76,77 Nevertheless, the possibility of metal support alloy formation can be ignored because we did not observe any significant peak shifting in the Sn 3d and O 1s core-level spectra. Rather, the work function difference between F-SnO 2 (∼4.4 eV) and Pt (5.5 eV) confirms the charge transfer process at the interface to equilibrate the respective Fermi levels.…”