Zn-Leaching Induced Rapid Self-Reconstruction of NiFe-Layered Double Hydroxides for Boosted Oxygen Evolution Reaction.

Optimizing the active centers through reconstruction is recognized as the key to construct high-performance oxygen evolution reaction (OER) catalysts. Herein, a simple and rapid in situ leaching strategy to promote the self-reconstruction of NiFe-layered double hydroxides (LDHs) catalysts is reported. The trace Zn dopants are introduced in advance by a facile and one-step hydrothermal method, followed by leaching over the electrochemical activation process, which can remarkably reduce the formation potential of NiFeOOH active centers to enable the deeper self-reconstruction for the formation of abundant highly active centers. Moreover, the self-restructured NiFeOOH-VZn cannot only significantly lower the dehydrogenation energy barrier for the transformation from Ni(OH)2 to NiOOH, but also decrease the free energy barrier of rate determining step for the *OH converted to *O through a deprotonation process, thus significantly boosting the OER behaviors. As a proof of concept, the obtained NiFeOOH-VZn catalyst just requires a low overpotential of 240 mV at 10 mA cm-2, and delivers robust stability at 50 mA cm-2 over 120 h, which outperforms the benchmark of noble metal RuO2 and those of most non-noble metal catalysts ever reported.

Enhanced Hygrothermal Stability of In-Situ-Grown MAPbBr3 Nanocrystals in Polymer with Suppressed Desorption of Ligands.

Currently, the intrinsic instability of organic-inorganic hybrid perovskite nanocrystals (PNCs) at high temperature and high humidity still stands as a big barrier to hinder their potential applications in optoelectronic devices. Herein, we report the controllable in-situ-grown PNCs in polyvinylidene fluoride (PVDF) polymer with profoundly enhanced hygrothermal stability. It is found that the introduced tetradecylphosphonic acid (TDPA) ligand enables significantly improved binding to the surface of PNCs via a strong covalently coordinated P-O-Pb bond, as evidenced by density functional theory calculations and X-ray photoelectron spectroscopy analyses. Accordingly, such enhanced binding could not only make efficient passivation of the surface defects of PNCs but also enable the remarkably suppressed desorption of the ligand from the PNCs under high-temperature environments. Consequently, the photoluminescence quantum yield (PL QY) of the as-fabricated MAPbBr3-PNCs@PVDF film exhibits almost no decay after exposure to air at 333 K over 1800 h. Once the temperatures are increased from 293 to 353 K, their PL intensity can be kept as 88.6% of the initial value, much higher than that without the TDPA ligand (i.e., 42.4%). Moreover, their PL QY can be maintained above 50% over 1560 h (65 days) under harsh working conditions of 333 K and 90% humidity. As a proof of concept, the as-assembled white light-emitting diodes display a large color gamut of 125% National Television System Committee standard, suggesting their promising applications in backlight devices.

Boosted photocatalytic hydrogen production over two-dimensional/two-dimensional Ta3N5/ReS2 van der Waals heterojunctions.

Currently, two-dimensional/two-dimensional (2D/2D) van der Waals heterojunctions, as novel and excellent candidates for photocatalysts, have attracted significant attention because of their fundamentally improved interfacial charge separation/transfer and massive reactive centers. Herein, novel 2D/2D Ta3N5-nanosheet/ReS2-nanosheet van der Waals heterojunction photocatalysts are rationally designed through a method combining template-assisted and solution-adsorption processes. The resultant heterojunctions exhibit enhanced interfacial charge transfer, boosted light absorption and significantly increased reaction sites for hydrogen evolution. Correspondingly, they deliver a high photocatalytic hydrogen production activity of 615 µmol g-1 h-1, which is ∼3 and ∼12 times greater than that of bare Ta3N5 nanosheets and ReS2 nanosheets, respectively, and superior to those in the most recent reports about photocatalytic water splitting on Ta3N5 material, implying their potential applications as advanced catalysts for hydrogen evolution.

Dimethyl Ferrocene-Induced Ambient-Processed High-Quality Films toward Efficient Perovskite Solar Cells for Industrial Application.

Metal halide perovskite solar cells (PSCs) have recently made significant progress with power conversion efficiencies (PCEs) boosted from 3.8% to a certified one over 26.1%, partially benefiting from the high-quality perovskite film enabled by the effective one-step spin-coating route. However, an extra antisolvent step with poor controllability and producibility is often involved in such a process, and some intrinsic defects are generated inevitably, especially in ambient atmospheric conditions, thus fundamentally limiting the commercialization of PSCs. Here, we introduce 1,1'dimethyl ferrocene into methylammonium lead halide precursor, which could not only recover the defects within perovskite film but also simplify the process without the extra antisolvent step. Accordingly, a dense and uniform perovskite film with large grains has been obtained under ambient conditions, which has much lower defect density, better stability against moisture penetration, and enhanced thermal tolerance than the control one, delivering a champion PCE of 16.92%. Current work sheds light on the simplified air-processed strategy for high-quality perovskite films, which might pave the way for exploring efficient and stable PSCs toward industrial applications.