Copper-Sulfur-Nitrogen Cluster Providing a Local Proton for Efficient Carbon Dioxide Photoreduction

Atomically precise Cu clusters are highly desirable as catalysts for CO2 reduction reaction (CO2 RR), and they provide an appropriate model platform for elaborating their structure-activity relationship. However, an efficient overall photocatalytic CO2 RR with H2 O using assembled Cu-cluster aggregates as single component photocatalyst has not been reported. Herein, we report a stable crystalline Cu-S-N cluster photocatalyst with local protonated N-H groups (denoted as Cu6 -NH). The catalyst exhibits suitable photocatalytic redox potentials, high structural stability, active catalytic species, and a narrow band gap, which account for its outstanding photocatalytic CO2 RR performance under visible light, with ≈100 % selectivity for CO evolution. Remarkably, systematic isostructural Cu-cluster control experiments, in situ infrared spectroscopy, and density functional theory calculations revealed that the protonated pyrimidine N atoms in the Cu6 -NH cluster act as a proton relay station, providing a local proton during the photocatalytic CO2 RR. This efficiently lowers the energy barrier for the formation of the *COOH intermediate, which is the rate-limiting step, efficiently enhancing the photocatalytic performance. This work lays the foundation for the development of atomically precise metal-cluster-based photocatalysts.

Silver Cluster-Porphyrin-Assembled Materials as Advanced Bioprotective Materials for Combating Superbacteria

Superbugs are bacteria that have grown resistant to most antibiotics, seriously threating the health of people. Silver (Ag) nanoparticles are known to exert a wide-spectrum antimicrobial property, yet remains challenging against superbugs. Here, Ag clusters are assembled using porphyrin-based linkers and a novel framework structure (Ag9 -AgTPyP) is produced, in which nine-nuclearity Ag9 clusters are uniformly separated by Ag-centered porphyrin units (AgTPyP) in two dimensions, demonstrating open permeant porosity. Ag9 -AgTPyP eliminates over 99.99999% and 99.999% methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) within 2 h upon visible-light irradiation, which are superior to a majority of bacteria inactivation photocatalysts. The novel-established long-term charge-transfer states from AgTPyP to adjacent Ag9 cluster that has preferential affinity to O2 greatly promote reactive oxygen species (ROS) production efficiency; and its unique framework accelerates the ROS transportation. Personal protective equipment (masks and protective suits) incorporating Ag9 -AgTPyP film also shows excellent performances against superbugs. This superbugs-killing efficiency is unprecedented among silver complexes and porphyrin derivatives. Utilizing efficient photogenerated electrons and holes between metal cluster and linkers can open up new interests of research in photocatalytic areas.