To achieve zero-carbon economy, advanced anode catalysts are desirable for hydrogen production and biomass upgrading powered by renewable energy. Ni-based non-precious electrocatalysts are considered as potential candidates because of intrinsic redox attributes, but in-depth understanding and rational design of Ni site coordination still remain challenging. Here, we perform anodic electrochemical oxidation of Ni-metalloids (NiPx, NiSx, and NiSex) to in-situ construct different oxyanion-coordinated amorphous nickel oxyhydroxides (NiOOH-TOx), among which NiOOH-POx shows optimal local coordination environment and boosts electrocatalytic activity of Ni sites towards selective oxidation of methanol to formate. Experiments and theoretical results demonstrate that NiOOH-POx possesses improved adsorption of OH* and methanol, and favors the formation of CH3O* intermediates. The coordinated phosphate oxyanions effectively tailor the d band center of Ni sites and increases Ni-O covalency, promoting the catalytic activity. This study provides additional insights into modulation of active-center coordination environment via oxyanions for organic molecules transformation.

Bright red emission (620-650 nm) from perovskite light-emitting diodes (PeLEDs) is usually achieved via a composition including both bromine and iodine anions, which results in poor performance and stability due to phase separation under operating conditions. Here a large-scale ligand-assisted reprecipitation method is devised with nonpolar solvent that enables the fabrication of CsPbI 3 nanowire clusters, emitting at 600 nm. The blue-shift of this emission relative to that of bulk CsPbI 3 (≈700 nm) is attributed to quantum confinement in nanowires. The growth of the nanowires is along the [011] crystal direction and is vacancy driven, resulting in the healing of surface defects and thereby a high photoluminescence quantum yield of 91%. The clusters with ultralow trap density show remarkable structural and environmental stability. PeLEDs based on these clusters exhibit an external quantum efficiency of 6.2% with Commission Internationale de l'Eclairage coordinates of (0.66, 0.34), and record luminance of 13 644 cd m −2 of red electroluminescence. The half-lifetime under an accelerated stability test is 13.5 min for an unencapsulated device in ambient conditions operating at an initial luminance of 11 500 cd m −2 , which corresponds to an estimated half-lifetime of 694 h at 100 cd m −2 based on acceleration factor obtained by experimental testing.

Developing efficient piezocatalytic systems for two-electron water splitting (TEWS) with producing H 2 and H 2 O 2 shows great promise to meet the industrial demand. Herein, Ag single atoms (SAs) and clusters are co-anchored on carbon nitride (Ag SA + C À CN) to serve as the multifunctional sites for efficient TEWS. The Ag SAs enhance the in-plane piezoelectric polarization of CN that is intimately modulated by the atomic coordination induced charge redistribution, and Ag clusters afford strong interfacial electric field to remarkably promote the out-of-plane migration of piezoelectrons from CN. Moreover, Ag SA + C À CN yields a larger piezoresistive effect that elevates carrier mobility under strain. Consequently, a superior H 2 and H 2 O 2 evolution rate of 7.90 mmol g À 1 h À 1 and 5.84 mmol g À 1 h À 1 is delivered by Ag SA + C À CN, respectively, far exceeding that of the previously reported piezocatalysts. This work not only presents the SAs decoration as an available polarization enhancement strategy, but also sheds light on the superiority of multi-sites engineering in piezocatalysis.

It is a big challenge to achieve pure-blue (≤470 nm) perovskite light-emitting diodes (PeLEDs) with high efficiency and stability. Here, we report pure-blue (electroluminescence at 469 nm) PeLEDs with a full width at halfmaximum of 21 nm, high external quantum efficiency of 10.3%, luminance of 12 060 cd m −2 , and continuous operation half-life of 25 h, representing the stateof-the-art performance. This design is based on strongly quantum confined CsPbBr 3 quantum dots (QDs) with suppression of Auger recombination, which was enabled by inorganic ligands, replacing initial organic ligands on the QDs. The inorganic ligand acts as a "capacitor" to alleviate the charge accumulation and reduce the exciton binding energy of the QDs, which suppresses the Auger recombination, resulting in much lower efficiency roll-off of PeLEDs. Thus, the devices maintain high efficiency (>10%) at high luminance (>2000 cd m −2 ), which is of considerable significance for the display application.

Despite quick development of perovskite light‐emitting diodes (PeLEDs) during the past few years, the fundamental mechanisms on how ion migration affects device efficiency and stability remain unclear. Here, it is demonstrated that the dynamic redistribution of mobile ions in the emissive layer plays a key role in the performance of PeLEDs and can explain a range of abnormal behaviours commonly observed during the device measurement. The dynamic redistribution of mobile ions changes charge–carrier injection and leads to increased recombination current; at the same time, the ion redistribution also changes charge transport and results in decreased shunt resistance current. As a result, the PeLEDs show hysteresis in external quantum efficiencies (EQEs) and radiance, that is, higher EQEs and radiance during the reverse voltage scan than during the forward scan. In addition, the changes on charge injection and transport induced by the ion redistribution also well explain the rise of the EQE/radiance values under constant driving voltages. The argument is further rationalized by adding extra formamidinium iodide (FAI) into optimized PeLEDs based on FAPbI3, resulting in more significant hysteresis and shorter operational stability of the PeLEDs.

Atomic-scale ferroelectrics are of great interest for high-density electronics, particularly field-effect transistors, low-power logic, and nonvolatile memories. We devised a film with a layered structure of bismuth oxide that can stabilize the ferroelectric state down to 1 nanometer through samarium bondage. This film can be grown on a variety of substrates with a cost-effective chemical solution deposition. We observed a standard ferroelectric hysteresis loop down to a thickness of ~1 nanometer. The thin films with thicknesses that range from 1 to 4.56 nanometers possess a relatively large remanent polarization from 17 to 50 microcoulombs per square centimeter. We verified the structure with first-principles calculations, which also pointed to the material being a lone pair–driven ferroelectric material. The structure design of the ultrathin ferroelectric films has great potential for the manufacturing of atomic-scale electronic devices.

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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.