Ultraviolet (UV) organic emitters that can open up applications for future organic light-emitting diodes (OLEDs) are of great value but rarely developed. Here, we report a highquality UV emitter with hybridized local and charge-transfer (HLCT) excited state and its application in UV OLEDs. The UV emitter, 2BuCz-CNCz, shows the features of low-lying locally excited (LE) emissive state and high-lying reverse intersystem crossing (hRISC) process, which helps to balance the color purity and exciton utilization of UV OLED. Consequently, the OLED based on 2BuCz-CNCz exhibits not only a desired narrowband UV electroluminescent (EL) at 396 nm with satisfactory color purity (CIE x, y = 0.161, 0.031), but also a record-high maximum external quantum efficiency (EQE) of 10.79 % with small efficiency roll-off. The state-ofthe-art device performance can inspire the design of UV emitters, and pave a way for the further development of highperformance UV OLEDs.

We report a new electrodeposition method for chitosan based on the coordination of chitosan to metal ions in situ-generated by simultaneous electrochemical oxidation.

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Carbon materials have been recognized as prospective catalysts for the electrocatalytic 1,2-dichloroethane (DCE) dechlorination reaction (DCEDR), which is an economical and environmentally friendly strategy for the control of DCE contamination and production of highly valuable ethylene. However, the precise nature of intrinsic defects (pentagon, heptagon, octagon, armchair edge, and zigzag edge) in carbon-based catalysts for the electrochemical DCEDR has not been reported to date. Herein, theoretical calculations demonstrated that pentagon site showed the lowest energy barrier of 0.12 eV, indicating a much higher electrochemical reactivity and ethylene selectivity of pentagon defect than those of others. The prediction results have been proved experimentally based on a series of defective carbon materials with definitive defect configurations. Therefore, intrinsic defects played a significant role in the electrocatalytic DCEDR and pentagon defect was responsible for the high performance of defective carbon catalysts. This work not only clarifies the nature of intrinsic defects in carbon materials for electrochemical DCEDR but also provides the design principles for the rational preparation of advanced carbon electrocatalysts.

Manganese−copper spinel is a kind of efficient catalyst for NO reduction by CO; however, its unsatisfactory lowtemperature catalytic performance and poor N 2 selectivity limit its application. Here, peanut-shaped Cu 0.75 Mn 2.25 O 4 nano-hollow spinel (Cu 0.75 Mn 2.25 O 4 -NH) was prepared by a one-pot solvothermal method and applied in NO reduction by CO. The structure and physicochemical properties of catalysts were researched by comprehensive characterizations. Compared with Cu 0 . 7 5 Mn 2 . 2 5 O 4 nanoparticles (Cu 0 . 7 5 Mn 2 . 2 5 O 4 -NP), Cu 0.75 Mn 2.25 O 4 -NH displayed excellent low-temperature catalytic performance, achieving 90% NO conversion at 200 °C, and possessed a lower apparent activation energy (36.4 kJ•mol −1 ). Importantly, the unique nanostructure with more exposed active sites enhanced the redox properties and oxygen mobility of the Cu 0.75 Mn 2.25 O 4 -NH catalyst. In addition, a synergistic effect between different metal ions in the Cu 0.75 Mn 2.25 O 4 -NH catalyst promoted the formation of oxygen vacancies and more low-oxidation-state species, which were conducive to the N−O bond scission at low temperatures. Combining the in situ DRIFTS results and DFT calculations, the dispersed species of Cu y+ -O-Mn x+ could be reduced to the main reactive species of Cu (y−1)+ -□-Mn (x−1)+ . Moreover, the formation of oxygen vacancies optimized NO adsorption and activation ability, which improved the catalytic performance in NO reduction by CO.