Development of lead-free inorganic perovskite material, such as Cs2AgBiBr6, is of great importance to solve the toxicity and stability issues of traditional lead halide perovskite solar cells. However, due to a wide bandgap of Cs2AgBiBr6 film, its light absorption ability is largely limited and the photoelectronic conversion efficiency is normally lower than 4.23%. In this text, by using a hydrogenation method, the bandgap of Cs2AgBiBr6 films could be tunable from 2.18 eV to 1.64 eV. At the same time, the highest photoelectric conversion efficiency of hydrogenated Cs2AgBiBr6 perovskite solar cell has been improved up to 6.37% with good environmental stability. Further investigations confirmed that the interstitial doping of atomic hydrogen in Cs2AgBiBr6 lattice could not only adjust its valence and conduction band energy levels, but also optimize the carrier mobility and carrier lifetime. All these works provide an insightful strategy to fabricate high performance lead-free inorganic perovskite solar cells.

NiFe-based hydroxides are considered as promising nonprecious catalysts for water oxidation due to their low cost and easy preparation. However, the rational design of NiFe-based electrocatalysts remains a great challenge to address the sluggish reaction kinetics and severe deactivation problems for oxygen evolution reaction (OER). Here, the authors report a facile approach to fabricate an amorphous Ce-doped NiFe hydroxide catalyst, which enables high activity and outstanding stability toward OER in alkaline media. The overpotential of electrodeposited amorphous Ce-doped NiFe is only 195 mV at 10 mA cm −2 . Meanwhile, the durability of the amorphous Ce-doped NiFe is maintained for 300 h at 100 mA cm −2 . The comprehensive characterization results reveal that the improved electrochemical performance of the amorphous Ce-doped NiFe catalyst is originated from the favorable oxidation transition of active sites enabled by Ce-doping. It is a very good strategy to introduce highly oxidized state ions to regulate the NiFe-based catalyst to improve the catalytic activity and stability.

Titanium dioxide (TiO2) nanocrystals have attracted great attention in heterogeneous photocatalysis and photoelectricity fields for decades. However, contradicting conclusions on the crystallographic orientation and exposed facets of TiO2 nanocrystals frequently appear in the literature. Herein, using anatase TiO2 nanocrystals with highly exposed {001} facets as a model, the misleading conclusions that exist on anatase nanocrystals are clarified. Although TiO2‐001 nanocrystals are recognized to be dominated by {001} facets, in fact, anatase nanocrystals with both dominant {001} and {111} facets always co‐exist due to the similarities in the lattice fringes and intersection angles between the two types of facets (0.38 nm and 90° in the [001] direction, 0.35 nm and 82° in the [111] direction). A paradigm for determining the crystallographic orientation and exposed facets based on transmission electron microscopy (TEM) analysis, which provides a universal methodology to nanomaterials for determining the orientation and exposed facets, is also given.

Significant challenges remain in developing rechargeable zinc batteries mainly because of reversibility problems on zinc‐metal anodes. The dendritic growth and hydrogen evolution on zinc electrodes are major obstacles to overcome in developing practical and safe zinc batteries. Here, a dendrite‐free and hydrogen‐free Zn‐metal anode with high Coulombic efficiency up to 99.6% over 300 cycles is realized in a newly designed nonaqueous electrolyte, which comprises an inexpensive zinc salt, zinc acetate, and a green low‐cost solvent, dimethyl sulfoxide. Surface transformation on Cu substrate plays a critical role in facilitating the dendrite‐free deposition process, which lowers the diffusion energy barrier of the Zn atoms, leading to a uniform and compact thin film for zinc plating. Furthermore, in situ electrochemical atomic force microscopy reveals the plating process via a layer‐by‐layer growth mechanism and the stripping process through an edge‐dissolution mechanism. In addition, Zn||Mo6S8 full cells exhibit excellent electrochemical performance in terms of cycling stability and rate capability. This work presents a new opportunity to develop nonaqueous rechargeable zinc batteries.

Iridium oxide is considered the only practical catalyst for oxygen evolution reaction (OER) in commercial proton exchange membrane (PEM) electrolyzers. However, its low activity and high cost greatly hinder the large-scale development of PEM electrolyzers for hydrogen production. Herein, we report atomically dispersed Ir atoms incorporated into a spinel Co3O4 lattice as an acidic OER catalyst, which exhibits excellent activity and stability for water oxidation. The catalyst significantly lowers the overpotential down to 226 mV at 10 mA cm–2 with an ultrahigh turnover frequency value of 3.15 s–1 (η = 300 mV), 3 orders of magnitude higher than that of commercial IrO2. Meanwhile, the catalyst shows superior corrosion resistance in an acidic OER condition, reaching a lifespan of up to 500 h at 10 mA cm–2. First-principles calculations reveal that the key *OOH intermediate can be stabilized by the lattice oxygen coordinated to the Ir active site via hydrogen bond formation, which substantially regulates the rate-limiting step and lowers the activation free energy of the OER process. This work demonstrates a strategy for improving the OER activity of Ir-based catalysts and provides insights into the regulation of the reaction mechanism.