Fe-Ni Diatomic Sites Coupled with Pt Clusters to Boost Methanol Electrooxidation via Free Radical Relaying

Highly amorphized nickel-based ternary metal catalysts for efficient urea oxidation reaction

Developing efficient catalysts for the urea oxidation reaction (UOR) is of critical importance in advancing sustainable energy. The transient loss of high-valence Ni active sites is one of the key factors limiting the reaction kinetics of UOR. To addressing this challenge, we successfully synthesize transition metal M (M = Mn, Co, Fe)-doped NiMoO4 amorphized self-supported electrodes (NiMoO4/M) through a two-step hydrothermal method. The NiMoO4/Mn shows superior stability and selectivity, achieving a current density of 100 mA cm-2 at an overpotential of 1.48 V (vs. RHE). The results reveal that the catalytic activity improvement stems from amorphized surface structure and the synergistic effects among Ni-Mo-M. During electrochemical reconstruction, ternary Ni-Mo-M active sites are formed, with Mo acting as an electron acceptor to regulate the electronic configuration of Ni. The doped metals further enhance the electron-accepting ability of Mo, facilitating electron transfer between Ni and Mo, optimizing the hydroxide-coupled electron transfer process, thereby accelerating UOR kinetics and advancing the process's efficiency. This study offers a strategic framework for designing highly efficient multi-metallic UOR catalysts through precise modulation of electronic and structural properties.

Sub-10 nm PdNi@PtNi Core-Shell Nanoalloys for Efficient Ethanol Electro-Oxidation

By controlling the structure and composition of Pt-based nanoalloys, the ethanol oxidation reaction (EOR) performances of Pt alloy catalysts can be effectively improved. Herein, we successfully synthesis sub-10 nm PdNi@PtNi nanoparticles (PdNi@PtNi NPs) with a core-shell structure by a one-pot method. The sub 10 nm core-shell nanoparticles possess more effective atoms and exhibit a synergistic effect which can lead to a shift in the d-band center and alter binding energies toward adsorbates. Due to the synergistic effect and unique core-shell structure, the PdNi@PtNi NP catalysts exhibit excellent electrocatalytic performance for ethanol oxidation reactions in alkaline, achieving 9.30 times more mass activity and 7.05 times more specific activity that of the state-of-the-art Pt/C catalysts. Moreover, the stability of PdNi@PtNi NPs was also greatly improved over PtNi nanoparticles, PtPd nanoparticles, and commercial Pt/C. This strategy provides a new idea for improving the electrocatalytic performance of Pt-based catalysts for EORs.

Mn Single-Atom Tuning Fe-N-C Catalyst Enables Highly Efficient and Durable Oxygen Electrocatalysis and Zinc-Air Batteries

Fe-N-C catalyst is one of most promising candidates for oxygen electrocatalysis reaction in zinc-air batteries (ZABs), but achieving sustained high activity is still a challenging issue. Herein, we demonstrate that introducing Mn single atoms into Fe-N-C (Mn1@Fe-N-C/CNTs) enables the realization of highly efficient and durable oxygen electrocatalysis performance and application in ZABs. Multiple characterizations confirm that Mn1@Fe-N-C/CNTs is equipped with Mn-N2O2 and Fe-N4 sites and Fe nanoparticles. The Mn-N2O2 sites not only tune the electron structure of Fe-Nx sites to enhance intrinsic activity, but also scavenge the attack of radicals from Fe-Nx sites for improvement in ORR durability. As a result, Mn1@Fe-N-C/CNTs exhibits enhanced ORR performance to traditional Fe-N-C catalysts with high E1/2 of 0.89 V vs reversible hydrogen electrode (RHE) and maintains ORR activity after 15 000 CV. Impressively, Mn1@Fe-N-C/CNTs also presents excellent OER activity and the difference (ΔE) between E1/2 of ORR and OER potential at 10 mA cm-2 (Ej10) is only 0.59 V, outperforming most reported catalysts. In addition, the maintainable bifunctional activity of Mn1@Fe-N-C/CNTs is demonstrated in ZABs with almost unchanged cycle voltage efficiency up to 200 h. This work highlights the critical role of Mn single atoms in enhancing ORR activity and stability, promoting the development of advanced catalysts.