Plasma-assisted defect engineering of N-doped NiCo2O4 for efficient oxygen reduction

Defect control is a promising way to enhance the electrocatalysis performance of metal oxides. Oxygen vacancy enriched NiCo₂O₄ was successfully prepared using cold plasma. Oxygen as a plasma-forming gas introduces oxygen vacancies via electron etching. The concentration of oxygen vacancies can be controlled by different plasma-forming gas. CoO, which formed on the plasma samples, is beneficial for quick charge transfer and electrocatalytic performance. A high amount of nitrogen atoms of up to 10.1% was doped on NiCo₂O₄ because of the enriched oxygen vacancies and improved the stability of the oxygen defects and the conductivity of the catalyst. Electrocatalytic studies showed that the plasma-induced N-doped NiCo₂O₄ shows enhanced electrocatalytic performance for the oxygen reduction reaction (ORR). It shows a typical four-electron process that considerably improves the current density and onset potential. The HO₂^- % was as low as 0.59% and current density was 4.9 mA cm^-2 at 0.2 V (Vs. RHE) on the plasma-treated NiCo₂O₄. Calculations based on density functional theory reveal the mechanism for the promotion of the catalytic ORR activity via plasma treatment. This increases the electron density near the Fermi level, reducing the work function, and changing the position of the d-band center.

High-Performance Pd3Pb Intermetallic Catalyst for Electrochemical Oxygen Reduction

Extensive efforts to develop highly active and strongly durable electrocatalyst for oxygen reduction are motivated by a need for metal-air batteries and fuel cells. Here, we report a very promising catalyst prototype of structurally ordered Pd-based alloys, Pd3Pb intermetallic compound. Such structurally ordered Pd3Pb/C exhibits a significant increase in mass activity. More importantly, compared to the conventional Pt/C catalysts, ordered Pd3Pb/C is highly durable and exhibits a much longer cycle life and higher cell efficiency in Zn-air batteries. Interestingly, ordered Pd3Pb/C possesses very high methanol tolerance during electrochemical oxygen reduction, which make it an excellent methanol-tolerant cathode catalyst for alkaline polymer electrolyte membrane fuel cells. This study provides a promising route to optimize the synthesis of ordered Pd-based intermetallic catalysts for fuel cells and metal-air batteries.

Fabrication of SiO2 incorporated ordered mesoporous TiO2 composite films as functional Pt supports for photo-electrocatalytic methanol oxidation

SiO₂ incorporated ordered mesoporous TiO₂ composite films were fabricated as an active support for methanol oxidation and excellent photoelectrocatalytic activity was obtained, showing great potential application prospects.

Facile synthesis of PdPt@Pt nanorings supported on reduced graphene oxide with enhanced electrocatalytic properties

In this work, a facile one-pot wet-chemical method was developed for the self-assembly of PdPt@Pt nanorings via in situ reduction of [PdCl4](2-) and [PtCl6](2-) at room temperature, which are simultaneously dispersed on reduced graphene oxide (rGO; denoted as PdPt@Pt/rGO). Hexadecylpyridinium chloride was demonstrated as a shape-directing agent and formic acid as a reducing agent during the reaction process. The as-prepared PdPt@Pt/rGO exhibited enhanced electrocatalytic activity and better stability for oxygen reduction reaction and ethanol oxidation reaction in acid media, compared with PtPd/rGO, Pt/rGO, Pd/rGO, Pt black, and Pt/C catalysts.

Non-thermal plasma-treated gold catalyst for CO oxidation

Plasma under oxygen atmosphere is available for promoting the microporosity, redox properties, and the catalytic performance of gold nanoparticles.