Search

Fe-N-C catalyst is the most promising alternative to platinum catalyst for proton-exchange membrane fuel cells (PEMFCs), however its high performance cannot be maintained for a long enough time in device. The construction of a new Fe coordination environment that is different from the square-planar Fe-N 4 configuration in Fe-N-C catalyst is expected to break current stability limits, which however remains unexplored. Here, we report the conversion of Fe-N-C to a new FeNxSey catalyst, where the Fe sites are three-dimensionally (3D) co-coordinated by N and Se atoms. The FeNxSey catalyst exhibits much better 4e- ORR activity and selectivity than the Fe-N-C catalyst. Specifically, the yields of H2O2 and ·OH radicals on FeNxSey are only one-quarter and one-third of that on Fe-N-C, respectively. Therefore, the FeNxSey catalyst exhibits outstanding stability, losing only 10 mV in E1/2 after 10,000 cycles, much smaller than that of the Fe-N-C catalyst (56 mV), representing the most stable Pt-free catalysts ever reported. Moreover, the 3D co-coordination structure inhibits the Fe demetallization in the presence of H2O2. As a result, the FeNxSey based PEMFC shows excellent durability, with the current density attenuation significantly lower than that of the Fe-N-C based device after accelerated durability testing., (© 2025 Wiley‐VCH GmbH.)

In this paper, a series of BaSrCaWO 6 :x%Mn 4+ , y%La 3+ (x = 0.1, 0.5, 0.6, 1.5; y = 0, 5, 10, 15, 20) red-emitting phosphors were synthesized by the high-temperature solid-state method. The structure and optical properties of the samples were systematically studied by the characterizations of x-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis spectra, photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, and quantum efficiency (QE). It was found that the addition of La 3+ ions plays significant roles on the luminous performance of phosphors as compared with the nonluminous BaSrCaWO 6 :Mn (BSCW:Mn), which can be attributed to the Mn 2+  → Mn 4+ oxidation process induced by La 3+ doping. The BSCW:0.5%Mn, 15%La 3+ phosphor exhibited a strong emission peak at 685 nm with a CIE chromaticity coordinate at (0.720, 0.279), which is suitable for application in indoor plant cultivations. The BSCW:0.5%Mn, 15%La 3+ phosphor exhibited an IQE of 47.8% and a high absorption efficiency of 72.8% with the EQE of 34.8%. Besides, the phosphor also showed the thermal stability with the emission intensity at 423 K being 48% of the emission intensity at 298 K. These results indicate that the synthesized BSCW:0.5%Mn, 15%La 3+ phosphor could be a potential phosphor to be applied in plant growth LEDs., (© 2025 John Wiley & Sons Ltd.)