CuNi Nanoalloys with Tunable Composition and Oxygen Defects for the Enhancement of the Oxygen Evolution Reaction**

Abstract

Colloidal synthesis is an excellent tool for the study of cooperative effects in nanoalloys. In this work, bimetallic CuNi nanoparticles of defined size and composition are fully characterized and tested for the oxygen evolution reaction. Copper addition to nickel leads to modifications in the structural and electronic properties, showing a higher concentration of surface oxygen defects and formation of active Ni3+ sites under reaction conditions. The ratio OV/OL between oxygen vacancies and lattice oxygen shows a clear correlation with the overpotential, being an excellent descriptor of the electrocatalytic activity. This is attributed to modifications in the crystalline structure, leading to lattice strain and grain size effects. Bimetallic Cu50Ni50NP showed the lowest overpotential (318 mV vs RHE), low Tafel slope (63.9 mV dec−1), and excellent stability. This work unravels the relative concentration between oxygen defects and lattice oxygen (OV/OL) as an excellent descriptor of the catalytic activity of bimetallic precatalysts.

Multistep Quenching of a Rust-Derived Catalyst for Enhanced Volatile Organic Compound Catalytic Oxidation

“…Moreover, the surface vacancy sites can be quantified by the calculated ratios of O M–OH to O M–OH + O latt (Table S3). , Compared with the ratio of Fe 2 O 3 (19.84%), the higher ratio of O M–OH to O M–OH + O latt on Sn s :Fe 2 O 3 (20.41%) and Sn q :Fe 2 O 3 (25.64%) indicated that the doping of Sn on Fe 2 O 3 would promote the generation of oxygen vacancy. Meanwhile, Sn q :Fe 2 O 3 exhibited a larger number of oxygen vacancies than Sn s :Fe 2 O 3 , suggesting that the quenching method further induced the generation of abundant vacancy sites.…”

CuNi Aerogels with Suppressed Water Activation for Efficient Nucleophilic Methanol Electrooxidation

“…Ni 2p 3/2 spectra were deconvoluted into two peaks at 852.4 and 855.8, which can be assigned to Ni(0) and Ni(OH) 2 , respectively (Figure c and Figure S7a). , Specifically, the content of Ni(OH) 2 on the surface rises with an increasing Cu content (Table S3), illustrating that the integration of Cu induces a more intrinsic content of the precatalytic site Ni 2+ due to the lower standard reduction potential of Ni/Ni 2+ (−0.24 V) compared to Cu/Cu 2+ (+0.34 V) . Theoretical calculations were performed to further confirm the foregoing conclusions.…”

Preparation of CuNi/NH2-MIL-125(Ti) for the photocatalytic synthesis of 1,4-dihydropyridines and β-acetamido ketones

“…32,50 The binding energy of Cu 2p 1/2 at 953.8 eV also proved the presence of Cu 0 and Cu 2+ . 32,51 This showed that Cu exists mainly in metallic form besides the presence of Cu 2 O and CuO on the CuNi NP surface. 32 The binding energies of Ni2p 1/2 and Ni2p 3/2 are found at ∼874.0 and 855.7 eV (Fig.…”