Electrocatalytic nitrate reduction for ammonia (eNIRR) is an ammonia production process that simultaneously removes nitrate contaminants from water. However, the lack of activity of cathode catalysts used as eNIRR catalysts is the main limiting factor for its development. Motivated by this fact, born-doped copper (BDCu) was obtained by using ZnO, which was easily removed at high temperature, as a dispersant, combined with weakly reducing boron clusters (closo-[B12H12]2-) as a reducing agent and B source during high-temperature pyrolysis. Impressively, BDCu demonstrated a Faradaic efficiency of 96.58% and a yield rate of 25741.51 mu g h-1 mgcat -1 toward ammonia production at -1.8 V (vs saturated calomel electrode). The ammonia yield rate of BDCu was twice as high as in the case of undoped B. Evolutionary behavior of NO3 - to NH3 conversion detected by in situ Fourier-transform infrared (in situ FT-IR) and electrochemical in situ mass spectrometry (in situ DEMS). Experimental and density functional theory (DFT) calculations explained that the activation of water was enhanced by B-doped Cu, and the adsorption of proton *H was weakened, which made it easy for *H to migrate away from the catalyst to NO3 - as a proton required for NO3 - reduction. In addition, the electron-deficient of B provides conditions for electron transfer between B and Cu. The electron transfer from Cu to B in BDCu led to a decrease in the center of the d-band of Cu, which modulated the electronic properties of Cu and altered the behavior of the NO3 - to NH3 transition on the Cu surface. Compared with Cu undoped B as well as unreduced CuO, BDCu lowered the energy barrier of the rate-determining step (*NO -> *N), allowing for a smoother conversion of NO3 - to NH3. This study provides a strategy to change the electronic structure of transition metals by B-modification and thus improve the performance of ammonia synthesis.

Although photoluminescence imaging-guided photodynamic therapy (PDT) is promising for theranostics, it easily suffers from tissue autofluorescence and PDT photoproducts. To develop time-resolved imaging (TRI)-guided PDT with long-lived emission pathways, like thermally activated delayed fluorescence (TADF), is urgent but challenging, because of the triplet competition between radiative transition and reactive oxygen species (ROS) production. Herein, skeleton-homologous nanoparticles are designed and constructed to address this dilemma, thereby achieving in vivo TRI-guided PDT for the first time. This system is formed with a lipophilic TADF core (as a TRI probe) encapsulated by an amphiphilic photosensitizer shell (as the corona exposed to oxygen for PDT), both of which are derived from the same donor-acceptor skeleton to minimize phase separation in the single entity, and enable the same long-wavelength photoexcitation for TRI and PDT. The chloropropylamine group is helpful for endoplasmic reticulum targeting to enhance PDT upon minimizing the ROS transmission path. Synchronously, the TADF core exhibits a delayed fluorescence of 40 mu s for a clear TRI. The NPs are eventually applied in vivo with a high signal-to-background ratio (45.25) and outstanding PDT effects in a mouse model of deep-seated kidney cancer. Such a material design is beneficial for developing high-efficient and high-contrast theranostic approaches.

The construction of visible-light-driven hybrid heterostructure photocatalysts is of great significance for environmental remediation, although the utilization of strong visible-light response photocatalysts with high efficiency and stability remains a major challenge. Defect engineering is an excellent way to introduce metal cation vacancies in materials, thereby ensuing in highly enhanced catalytic performance. Inspired by this, we effectively constructed a built-in interface alpha-MnO2/Bi2WO6 heterostructure with abundant intimate interfaces and defective Mn3+/Mn4+ active sites for photocatalytic tetracycline hydrochloride (TC-HCl), hexavalent chromium Cr6+ reduction, and Escherichia coli (E. coli) inactivation. The experimental results, such as the active species test and X-ray photoelectron spectroscopy, indicated that the defective sites Mn3+/Mn4+, surface oxygen vacancies, and Bi(3+x)+ boosted the visible light absorption, and highly enhanced the photoinduced charge separation/transfer. Furthermore, experimental and DFT calculations reveal the high charge density at the built-in interface heterostructure and the Z-scheme charge transfer mechanism during the photocatalytic process. The results further reveal that O-2(-) and O-1(2) are the main reactive active species contributing to the photocatalytic reaction. The exceptional TC-HCl decomposition activity of the alpha-MnO2/Bi2WO6 heterostructure (97.56%, 2.31, and 2.04 times higher than bulk), enhanced reaction kinetics (K-app = 0.041 min(-1), 6.4, and 5.2 times higher than bulk), removal rate of 80.3%, Cr6+ reduction to Cr3+ (98.56%, K-app = 0.0599 min(-1)), and almost 100% bacterial inactivation compared to bulk alpha-MnO2 (42.22%) and Bi2WO6 (47.76%), were mainly due to the enhanced charge separation/transfer at the built-in interface and high charge density. This study opens new horizons for constructing Z-scheme MnO-based interface heterostructures with abundant defect sites for exceptional photocatalytic applications.