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Designing robust catalysts for increasing the sluggish kinetics of the urea oxidation reaction (UOR) is challenging. Herein, the regulation of spin states for metal active sites by photoexcitation to facilitate the adsorption of urea and intermediates is demonstrated. Mo-doped nickel sulfide nanoribbon arrays (Mo-Ni 3 S 2 @NMF) with excellent light-trapping capacity are successfully prepared. Under AM 1.5G illumination, the activity of the Mo-Ni 3 S 2 @NMF exhibits a 50% improvement in the UOR current. Compared with those under dark conditions, Mo-Ni 3 S 2 @NMF achieve 10 mA cm -2 at 1.315 V RHE for UOR and 1.32 V cell for urea electrolysis, which are decreases of 15 and 80 mV, respectively. The electron spin resonance, in situ Fourier transform infrared spectroscopy analysis and density functional theory calculations reveal that illumination led to the formation of Ni 3+ active sites in a high-spin state, which strengthens the d-p orbital hybridization of Ni-N, hence facilitating the adsorption of urea. C─N cleavage of the * CONN intermediate is further inhibited, which promotes the oxidation of urea molecules via the active N 2 pathway, thereby accelerating the UOR rate., (© 2024 Wiley‐VCH GmbH.)

Developing low-loading platinum-group-metal (PGM) catalysts is one of the key challenges in commercializing anion-exchange-membrane-fuel-cells (AEMFCs), especially for hydrogen oxidation reaction (HOR). Here, ruthenium-iridium nanoparticles being deposited on a Zn-N species-doped carbon carrier (Ru 6 Ir/Zn-N-C) are synthesized and used as an anodic catalyst for AEMFCs. Ru 6 Ir/Zn-N-C shows extremely high mass activity (5.87 A mg PGM -1 ) and exchange current density (0.92 mA cm -2 ), which is 15.1 and 3.9 times that of commercial Pt/C, respectively. Based on the Ru 6 Ir/Zn-N-C AEMFCs achieve a peak power density of 1.50 W cm -2 , surpassing the state-of-the-art commercial PtRu catalysts and the power ratio of the normalized loading is 14.01 W mg PGM anode -1 or 5.89 W mg PGM -1 after decreasing the anode loading (87.49 µg cm -2 ) or the total PGM loading (0.111 mg cm -2 ), satisfying the US Department of Energy's PGM loading target. Moreover, the solvent and solute isotope separation method is used for the first time to reveal the kinetic process of HOR, which shows the reaction is influenced by the adsorption of H 2 O and OH - . The improvement of the hydrogen bond network connectivity of the electric double layer by adjusting the interfacial H 2 O structure together with the optimized HBE and OHBE is proposed to be responsible for the high HOR activity of Ru 6 Ir/Zn-N-C., (© 2024 Wiley‐VCH GmbH.)

The development of high-performance, stable and platinum-free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline media is crucial for the commercial application of anion exchange membrane fuel cells (AEMFCs). Ruthenium, as an emerging HOR electrocatalyst with a price advantage over platinum, still needs to solve the problems of low intrinsic activity and easy oxidation. Herein, Ru nanoparticles are anchored on the oxygen-vacancy-rich metalloid WO 2.9 by interfacial engineering to create abundant and efficient Ru and WO 2.9 interfacial active sites for accelerated HOR in alkaline media. Ru/WO 2.9 /C displays excellent catalytic activity with mass activity (8.29 A mg NM -1 ) and specific activity (1.32 mA cm NM -2 ), which are 2.5/3.3 and 21.8/8.3 times that of PtRu/C and Pt/C, respectively. Moreover, Ru/WO 2.9 /C exhibits excellent CO tolerance and operational stability. Experimental and theoretical studies reveal that the improved charge transfer from Ru to WO 2.9 in the metal/metalloid heterostructure significantly tune the electronic structure of Ru sites and optimize the hydrogen binding energy (HBE) of Ru. While, WO 2.9 provides abundant hydroxyl adsorption sites. Therefore, the equilibrium adsorption of hydrogen and hydroxyl at the interface of Ru/WO 2.9 will be realized, and the oxidation of metal Ru would be avoided, thereby achieving excellent HOR activity and durability., (© 2024 Wiley‐VCH GmbH.)

Potassium-ion batteries (PIBs) have attracted more and more attention as viable alternatives to lithium-ion batteries (LIBs) due to the deficiency and uneven distribution of lithium resources. However, it is shown that potassium storage in some compounds through reaction or intercalation mechanisms cannot effectively improve the capacity and stability of anodes for PIBs. The unique anti-spinel structure of magnetite (Fe 3 O 4 ) is densely packed with thirty-two O atoms to form a face-centered cubic (fcc) unit cell with tetrahedral/octahedral vacancies in the O-closed packing structure, which can serve as K + storage sites according to the density functional theory (DFT) calculation results. In this work, carbon-coated Fe 3 O 4 @C nanoparticles are prepared as high-performance anodes for PIBs, which exhibit high reversible capacity (638 mAh g -1 at 0.05 A g -1 ) and hyper stable cycling performance at ultrahigh current density (150 mAh g -1 after 9000 cycles at 10 A g -1 ). In situ XRD, ex-situ Fe K-edge XAFS, and DFT calculations confirm the storage of K + in tetrahedral/octahedral vacancies., (© 2023 Wiley-VCH GmbH.)