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Magnesium hydride (MgH2) is an exceptional material for hydrogen storage, but its high desorption temperature and slow kinetics limit its applicability. In this study, the hydrogen storage performance of MgH2 was enhanced using highly dispersed Ni-nanoparticle–doped hollow spherical vanadium nitride (Ni/VN), which was synthesized via a solvothermal process. The MgH2 system doped with the synthesized Ni/VN exhibited an outstanding hydrogen-storage capability. Specifically, 5.6 wt.% of H2 was released within 1 h at a relatively low temperature of 513 K, whereas 6.4 wt.% of H2 was released within 180 s at 598 K, followed by an almost complete dehydrogenation after 10 min at 598 K. At 423 K, the developed material absorbed ∼6.0 wt.% of H2 within 5 min. The activation energy for dehydrogenation was determined to be 78.07 ± 2.91 kJ·mol−1, which was considerably lower than that of MgH2 produced by ball milling (120.89 ± 5.74 kJ·mol−1), corresponding to a reduction of 35.4%. It was deduced that the formation of Mg2Ni/Mg2NiH4 (hydrogen pump) through the reaction of Ni nanoparticles during dehydrogenation/hydrogenation facilitated hydrogen transport and synergistically catalyzed hydrogen absorption and desorption by MgH2, improving its hydrogen storage capability. These findings offer novel perspectives for the utilization of MgH2 in large-scale applications.

Abstract The limited sensitivity of photovoltaic-type photodiodes makes it indispensable to use pre-amplifier circuits for effectively extracting electrical signals, especially when detecting dim light. Additionally, the photomultiplication photodiodes with light amplification function suffer from potential damages caused by high power consumption under strong light. In this work, by adopting the synergy strategy of thermal-induced interfacial structural traps and blocking layers, we develop a dual-mode visible-near infrared organic photodiode with bias-switchable photomultiplication and photovoltaic operating modes, exhibiting high specific detectivity (~1012 Jones) and fast response speed (0.05/3.03 ms for photomultiplication-mode; 8.64/11.14 μs for photovoltaic-mode). The device also delivers disparate external quantum efficiency in two optional operating modes, showing potential in simultaneously detecting dim and strong light ranging from ~10−9 to 10−1 W cm−2. The general strategy and working mechanism are validated in different organic layers. This work offers an attractive option to develop bias-switchable multi-mode organic photodetectors for various application scenarios.