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No matter photoinduced organic radicals have been reported frequently, they are usually non‐luminescent at ambient conditions. The internal mechanism on stability and electronic transitions of photoinduced radicals, is thus crucial for the development of relevant materials. Herein, a series of photoinduced radical emission systems were developed conveniently through doping benzoic acids into the hydrogen donor polyvinyl alcohol (PVA) matrix. Visual photoinduced radical emission and photochromism could be observed on Ph‐3COOH@PVA film with the formation of cyclohexadienyl‐type structure. For the first time, radical afterglow appeared with energy transfer from triplet state. The appropriate introduction of carboxylic groups to three nonadjacent carbon atoms on the benzene ring was the best for decreasing spin population and promoting electronic transitions of the radical. This study largely expands the radical emission property from both internal mechanism and practical application. [ABSTRACT FROM AUTHOR]

Multiple amplification of tumor oxidative stress has been demonstrated as efficient strategy to enhance the reactive oxygen species (ROS)‐mediated cancer therapy. Herein, vanadium‐based nanocatalysts, hydrogen vanadium bronzes (HXV2O5, for short HVO), were constructed and employed as novel biocatalysts for amplifying tumor oxidative stress and enhancing cancer catalytic therapy. Such HVO nanocatalysts harboring multivalent V element possessed multi‐functional catalytic activity in decomposing H2O2 into ⋅OH and depleting endogenous glutathione (GSH) to dually amplify tumor oxidative stress. Meanwhile, HVO nanocatalysts could also be activated by ultrasound to further triply amplify oxidative stress. The massive intracellular ROS caused mitochondrial dysfunction, DNA damage, cell cycle arrest, and cell proliferation inhibition, further realizing cancer cell death and tumor growth inhibition. Collectively, HVO nanocatalysts highlight the remarkable value of ROS‐mediated cancer therapies. [ABSTRACT FROM AUTHOR]

Dual‐metal single‐atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual‐metal single‐atom catalyst consisted of Cu−N4 and Zn−N4 on the N‐doped carbon support (Cu/Zn−NC). It exhibits high‐efficiency ORR activity with an Eonset of 0.98 V and an E1/2 of 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state‐of‐the‐art Pt/C and great mass of Pt‐free single atom catalysts. Operando XANES demonstrates that the Cu−N4 as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn−N4 during ORR process, and then turns to single atom state again after reaction. DFT calculation further indicates that the adjustment effect of Zn on the d‐orbital electron distribution of Cu could benefit to the stretch and cleavage of O‐O on Cu active center, speeding up the process of rate determining step of OOH*. [ABSTRACT FROM AUTHOR]