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Coordinatively unsaturated metal sites in metal–organic frameworks (MOFs) hold promises for improving activity and selectivity of catalyst. As the building unit of many MOFs, copper paddle-wheel (CPW) is of great interest to function as activity sites for CO2 reduction due to the ability of copper cations to attract and activate CO2 molecules. However, little is known about the real structure of these active sites for their dynamic structural changes under realistic operating conditions. Here, we apply to design defect metal−organic framework HKUST-1 with coordinatively unsaturated copper paddle wheel through a facile “atomized trimesic acid” strategy, reveal its dynamic behaviour during electrochemical reconstruction and prove its superior CO2 reduction activity. Through comprehensive analysis of various in situ spectroscopy characterizations, it is demonstrated that unsaturated copper paddle wheel clusters [CU-CPWC, Cu2(HCOO)3] are finally formed during electrochemical reconstruction and act as the real active sites. Mechanistic studies based on density functional theory calculations reveal that the higher d band center in CU-CPWC compared with that in CPW accelerates the electron transport from copper atoms to CO2 molecules, which can be exploited to improve the CO2 reduction performance.

Based on the Novachip ultra-thin layer project in the expressway, the material characteristics, mixture design and road performance of Novachip asphalt mixture are introduced. The application effect of Novachip ultra-thin layer was observed. The results show that Novachip ultra-thin layer has no obvious effect on improving the smoothness of the original road surface. Novachip ultra-thin layer has obvious effect on improving the rutting, and has a good anti-skid performance.

Developing a facile strategy for universal synthesis of transition metal catalysts is significant to catalytic reactions but remains challenging. Herein, we report an ultrafast one-step electrodeposition method to prepare a series of transition metal foams within one minute for electrocatalytic water splitting. The porous metal foams not only possess unique 3D channels for rapid electrolyte diffusion and gas releasing, but also have robust integrated structures with enhanced conductivity for efficient charge transport. Consequently, the NiCo and NiFe foams only require 86 and 206 mV to output 10 mA cm−2 for hydrogen and oxygen evolution reactions (HER and OER) in 1 M KOH, respectively. Combining the two electrocatalysts, we have assembled an outstanding alkaline electrolyzer, requiring only 1.52 and 1.64 V to deliver 10 and 100 mA cm−2 respectively, outperforming the RuO2(+)//Pt/C(-) electrolyzer. Our study offers an ultrafast and general approach to fabricate 3D porous electrocatalysts for high-performance water splitting.