Quasi-two-dimensional (quasi-2D) Ruddlesden–Popper (RP) perovskites such as BA2Csn–1PbnBr3n+1 (BA = butylammonium, n > 1) are promising emitters, but their electroluminescence performance is limited by a severe non-radiative recombination during the energy transfer process. Here, we make use of methanesulfonate (MeS) that can interact with the spacer BA cations via strong hydrogen bonding interaction to reconstruct the quasi-2D perovskite structure, which increases the energy acceptor-to-donor ratio and enhances the energy transfer in perovskite films, thus improving the light emission efficiency. MeS additives also lower the defect density in RP perovskites, which is due to the elimination of uncoordinated Pb2+ by the electron-rich Lewis base MeS and the weakened adsorbate blocking effect. As a result, green light-emitting diodes fabricated using these quasi-2D RP perovskite films reach current efficiency of 63 cd A−1 and 20.5% external quantum efficiency, which are the best reported performance for devices based on quasi-2D perovskites so far.

Lead halide perovskite nanocrystals (PeNCs) are promising materials for applications in optoelectronics. However, their environmental instability remains to be addressed to enable their advancement into industry. Here the development of a novel synthesis method is reported for monodispersed PeNCs coated with all inorganic shell of cesium lead bromide (CsPbBr3) grown epitaxially on the surface of formamidinium lead bromide (FAPbBr3) NCs. The formed FAPbBr3/CsPbBr3 NCs have photoluminescence in the visible range 460–560 nm with narrow emission linewidth (20 nm) and high optical quantum yield, photoluminescence quantum yield (PLQY) up to 93%. The core/shell perovskites have enhanced optical stability under ambient conditions (70 d) and under ultraviolet radiation (50 h). The enhanced properties are attributed to overgrowth of FAPbBr3 with all‐inorganic CsPbBr3 shell, which acts as a protective layer and enables effective passivation of the surface defects. The use of these green‐emitting core/shell FAPbBr3/CsPbBr3 NCs is demonstrated in light‐emitting diodes (LEDs) and significant enhancement of their performance is achieved compared to core only FAPbBr3‐LEDs. The maximum current efficiency observed in core/shell NC LED is 19.75 cd A‐1 and the external quantum efficiency of 8.1%, which are approximately four times and approximately eight times higher, respectively, compared to core‐only devices.

This paper describes the design of Ni/SiO 2 catalysts obtained from a phyllosilicate precursor that possess high activity and stability for bioethanol steam reforming to sustainably produce hydrogen. Sintering of metal particles and carbon deposition are two major issues of nickel-based catalysts for reforming processes, particularly at high temperatures; strong metal−support interaction could be a possible solution. We have successfully synthesized Ni-containing phyllosilicates by an ammonia evaporation method. Temperature programmed reduction results indicate that the metal− support interaction of Ni/SiO 2 catalyst prepared by ammonia evaporation method (Ni/SiO 2P ) is stronger due to the unique layered structure compared to that prepared by conventional impregnation (Ni/SiO 2I ). With the phyllosilicate precursor nickel particles highly disperse on the surface, remaining OH groups in the unreduced phyllosilicates promote nickel dispersion and carbon elimination. We also show that high dispersion of Ni and strong metal−support interaction of Ni/SiO 2P significantly promote ethanol conversion and H 2 production in ethanol steam reforming. Ni/SiO 2P produces less carbon deposition compared to Ni/SiO 2I ; for the latter, a surface layer of Ni 3 C formed during the deactivation.

This paper describes an investigation regarding the influence of Ni precursors on catalytic performances of Ni/ Al 2 O 3 catalysts in glycerol steam reforming. A series of Ni/ Al 2 O 3 is synthesized using four different precursors, nickel nitrate, nickel chloride, nickel acetate, and nickel acetylacetonate. Characterization results based on N 2 adsorption− desorption, X-ray diffraction, H 2 temperature-programmed reduction, H 2 chemisorption, transmission electron microscopy, and thermogravimetric analysis show that reduction degrees of nickel, nickel dispersion, and particle sizes of Ni/ Al 2 O 3 catalysts are closely dependent on the anion size and nature of the nickel precursors. Ni/Al 2 O 3 prepared by nickel acetate possesses the moderate Ni reduction degree, high Ni dispersion, and small nickel particle size, which possesses the highest H 2 yield. Reaction parameters are also examined, and 550 °C and a steam-to-carbon ratio of 3 are optimized. Moreover, coke deposition, mainly graphite species, leads to the deactivation of Ni/Al 2 O 3 catalysts in glycerol steam reforming. Nickel chloridederived Ni/Al 2 O 3 catalysts suffer from severe coke deposition and low reaction activity due to large Ni particle size, low Ni dispersion, and residual chloride.