Dendritic defect-rich palladium–copper–cobalt nanoalloys as robust multifunctional non-platinum electrocatalysts for fuel cells

Abstract

Recently, the development of high-performance non-platinum electrocatalysts for fuel cell applications has been gaining attention. Palladium-based nanoalloys are considered as promising candidates to substitute platinum catalysts for cathodic and anodic reactions in fuel cells. Here, we develop a facile route to synthesize dendritic palladium–copper–cobalt trimetallic nanoalloys as robust multifunctional electrocatalysts for oxygen reduction and formic acid oxidation. To the best of our knowledge, the mass activities of the dendritic Pd59Cu30Co11 nanoalloy toward oxygen reduction and formic acid oxidation are higher than those previously reported for non-platinum metal nanocatalysts. The Pd59Cu30Co11 nanoalloys also exhibit superior durability for oxygen reduction and formic acid oxidation as well as good antimethanol/ethanol interference ability compared to a commercial platinum/carbon catalyst. The high performance of the dendritic Pd59Cu30Co11 nanoalloys is attributed to a combination of effects, including defects, a synergistic effect, change of d-band center of palladium, and surface strain.

Fine‐Tuning Intrinsic Strain in Penta‐Twinned Pt–Cu–Mn Nanoframes Boosts Oxygen Reduction Catalysis

“…In particular, the band energy of Pt–Cu–Mn UNFs has a positive shift compared with that of Pt–Cu–Mn PNFs. It indicates the downshift of the d‐band center, which is consistent with the results of surface valance band photoemission spectrum. Note that the ratio of oxidized state (Pt 2+ + Pt 4+ ) of Pt in Pt–Cu–Mn PNFs and Pt–Cu–Mn UNFs is ≈41.8% and 33.9%, respectively.…”

“…Moreover, abundant twin boundaries and atomic steps exist on the ridge and edge, respectively (Figure 1d,e). This indicates that the Pt–Cu–Mn UNFs possess rich crystal defects, which are generally considered as the excellent catalytic activity sites . The high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and the corresponding energy‐dispersive X‐ray spectroscopy (EDS) elemental mapping images reveal the uniform distribution of Pt, Cu, and Mn in the Pt–Cu–Mn UNFs (Figure 1f).…”

Defect-Rich, Candied Haws-Shaped AuPtNi Alloy Nanostructures for Highly Efficient Electrocatalysis

“…14,30 Second, previous reports have demonstrated that crystal defects could modulate the electronic structure and surface reactivity of metal NSs, and thus, improve their electrocatalytic activity. 14,23 In our work, the fabrication of AuPtNi NSs with rich crystal defects like twins, stacking faults, and atomic steps possessed a high density of low-coordinate atoms (Figure 1d-j), was able to facilitate the oxidation of methanol and ethanol via an enhancement of the electrocatalytic performance of the AuPtNi NSs toward the MOR and EOR. Third, the synergistic structural and electronic effects among the combined structural Au, Pt, and Ni also reinforced the electrocatalytic activity of the AuPtNi NSs toward the MOR and EOR.…”

“…As known, the defects such as twins, 14,18,19 stacking faults, 20 atomic steps, [21][22][23] and lattice strain 12,24,25 in metallic NSs could modulate their electronic structures and surface activities, and thus, improve their electrocatalytic performance. However, defect engineering of multimetallic NSs with desired composition, morphology, and surface structure, which further optimizes their stability and activity, remains a significant challenge.…”

Rh/Ce0.25Zr0.75O2 Catalyst for Steam Reforming of Propane at Low Temperature

“…Energy‐saving technological innovations such as fuel cells are in high demand around the world. Fuel cells can directly convert chemical energy into electrical energy more efficiently than internal‐combustion engines and have therefore attracted considerable attention as environmentally friendly power‐generation devices . Among the various types of fuel cells, solid oxide fuel cells (SOFCs) show the highest energy‐conversion efficiency and therefore emit less CO 2 than conventional combustion engines .…”