Palladium (Pd) is regarded as one of the most active catalysts for electrochemical ethylene glycol oxidation reaction (EGOR) to value-added glycolate, but its large-scale application is still restricted by limited catalytic effectiveness and exorbitant cost. Herein, we designed and synthesized the defect-rich nickel sulfide nanosheet arrays on nickel foam (Ni3−xCoxS2@NF) as the self-supported substrate to anchor well-dispersive Pd nanoparticles (Pd-Ni3−xCoxS2@NF) with its loading as low as approximately 3.03 wt.%, which is conducive to the exposure and utilization of the active Pd sites. The optimal Pd-Ni3−xCoxS2@NF electrocatalyst (1 cm2 working area) could achieve an efficient EGOR performance, showing a current density of 100 mA·cm−2 at 0.77 V vs. reversible hydrogen electrode (RHE), and 98.1% Faradaic efficiency of glycolate. Furthermore, the in-situ Raman spectra reveal that the interaction between Pd and Ni3−xCoxS2@NF significantly increases the adsorption of EG, and Ni3−xCoxS2@NF enhances the *OH adsorption capacity, thus further improving the EGOR activity and stability. This study provides an effective paradigm for enhancing the utilization and electrocatalytic performance of noble metallic catalysts, and also offers a deep insight into the interaction between the active sites and substrate.
- Article type
- Year
- Co-author
Open Access
Research Article
Issue
The anodic electrooxidation of ethanol to value-added acetate is an excellent example of replacing the oxygen evolution reaction to promote the cathodic hydrogen evolution reaction and save energy. Herein, we present a colloidal strategy to produce Ni-Fe bimetallic alloy nanoparticles (NPs) as efficient electrocatalysts for the electrooxidation of ethanol in alkaline media. Ni-Fe alloy NPs deliver a current density of 100 mA·cm−2 in a 1.0 M KOH solution containing 1.0 M ethanol merely at 1.5 V vs. reversible hydrogen electrode (RHE), well above the performance of other electrocatalysts in a similar system. Within continuous 10 h testing at this external potential, this electrode is able to produce an average of 0.49 mmol·cm−2·h−1 of acetate with an ethanol-to-acetate Faradaic efficiency of 80%. A series of spectroscopy techniques are used to probe the electrocatalytic process and analyze the electrolyte. Additionally, density functional theory (DFT) calculations demonstrate that the iron in the alloy NPs significantly enhances the electroconductivity and electron transfer, shifts the rate-limiting step, and lowers the energy barrier during the ethanol-to-acetate reaction pathway.
Open Access
Article
Issue
Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction (ORR) but remains a major challenge. In this work, we used a facile approach to synthesize iron nanoparticles encapsulated in nitrogen-doped porous carbon materials (Fe@N-C) from functionalized metal-organic frameworks (MOFs, MET-6). Embedding Fe nanoparticles into the carbon skeleton increases the graphitization degree and the proportion of graphitic N as well as promotes the formation of mesopores in the catalyst. The Fe@N-C-30 catalyst showed the excellent ORR activity in alkaline solutions (E0 = 0.97 V vs. RHE, E1/2 = 0.89 V vs. RHE). Moreover, the Fe@N-C-30 catalyst exhibited better methanol resistance and long-term stability when compared to commercial Pt/C. The superior ORR performance could be attributed to the combination of high electrochemical surface area, relative high portion of graphitic-N, unique porous structures and the synergistic effect between the encapsulated Fe particles and the N-doped carbon layer. This work provides a promising method to construct efficient non-precious-metal ORR catalyst through MOFs.
Open Access
Article
Issue
Lithium (Li) metal as an anode material for batteries has extremely high specific capacity and extremely low redox potential, which can significantly improve the energy density of the battery. However, the main problems faced by the use of Li metal anodes are Li dendrite growth, interfacial side reaction and volumetric change of electrode. Herein, a strategy to prepare the three-dimensional (3D) Li foam by combining 3D scaffold with quantitative Li was proposed to suppress Li dendrites growth and alleviate electrode volumetric change. The 3D Li foam facilitated the efficient utilization of Li metal by suppressing the Li dendrite growth, mitigating the volumetric change, and improving the rate performance. Therefore, the cycling lifetime and rate performance of the symmetric cells using the 3D Li foam were improved. The EIS results showed that the 3D Li foam reduced the charge transfer resistance of the symmetric cells. And the average discharge specific capacity of the LTO cell during 1000 cycles was enhanced from 65 mAh·g-1 to 121 mAh·g-1 by using the 3D Li foam.
京公网安备11010802044758号