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Controllable design of the catalytic electrodes with hierarchical superstructures is expected to improve their electrochemical performance. Herein, a self-supported integrated electrode (NiCo-ZLDH/NF) with a unique hierarchical quaternary superstructure was fabricated through a self-sacrificing template strategy from the metal–organic framework (Co-ZIF-67) nanoplate arrays, which features an intriguing well-defined hierarchy when taking the unit cells of the NiCo-based layered double hydroxide (NiCo-LDH) as the primary structure, the ultrathin LDH nanoneedles as the secondary structure, the mesoscale hollow plates of the LDH nanoneedle arrays as the tertiary structure, and the macroscale three-dimensional frames of the plate arrays as the quaternary structure. Notably, the distinctive structure of NiCo-ZLDH/NF can not only accelerate both mass and charge transfer, but also expose plentiful accessible active sites with high intrinsic activity, endowing it with an excellent electrochemical performance for urea oxidation reaction (UOR). Specially, it only required the low potentials of 1.335, 1.368 and 1.388 V to deliver the current densities of 10, 100 and 200 mA cm−2, respectively, much superior to those for typical NiCo-LDH. Employing NiCo-ZLDH/NF as the bifunctional electrode for both anodic UOR and cathodic HER, an energy-saving electrolysis system was further explored which can greatly reduce the needed voltage of 213 mV to deliver the current density of 100 mA cm−2, as compared to the conventional water electrolysis system composed of OER. This work manifests that it is prospective to explore the hierarchically nanostructured electrodes and the innovative electrolytic technologies for high-efficiency electrocatalysis.

Abstract The coupling electrosynthesis involving CO2 upgrade conversion is of great significance for the sustainable development of the environment and energy but is challenging. Herein, we exquisitely constructed the self‐supported bimetallic array superstructures from the Cu(OH)2 array architecture precursor, which can enable high‐performance coupling electrosynthesis of formate and adipate at the anode and the cathode, respectively. Concretely, the faradaic efficiencies (FEs) of CO2‐to‐formate and cyclohexanone‐to‐adipate conversion simultaneously exceed 90% at both electrodes with excellent stabilities. Such high‐performance coupling electrosynthesis is highly correlated with the porous nanosheet array superstructure of CuBi alloy as the cathode and the nanosheet‐on‐nanowire array superstructure of CuNi hydroxide as the anode. Moreover, compared to the conventional electrolysis process, the cell voltage is substantially reduced while maintaining the electrocatalytic performance for coupling electrosynthesis in the two‐electrode electrolyzer with the maximal FEformate and FEadipate up to 94.2% and 93.1%, respectively. The experimental results further demonstrate that the bimetal composition modulates the local electronic structures, promoting the reactions toward the target products. Prospectively, our work proposes an instructive strategy for constructing adaptive self‐supported superstructures to achieve efficient coupling electrosynthesis.

Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants, typically by creating active air infiltration through the difference between supply and exhaust air volumes. The door gap is the channel of air flow between rooms, so its height has an important influence on the pressure difference and infiltration air volume of the room. There is still a lack of research on setting reasonable ventilation strategies according to the different heights of door gaps at different positions in the building. In this study, model of a set of isolation wards was established and analyzed using the multi-zone simulation software CONTAM, and the ventilation strategies with different heights of door gaps were applied to the actual infection diseases department. The results show that in a building with ventilation system divided by functional area, the difference in the height of the door gaps requires different active infiltration air volumes. Pressure fluctuations in the medical and patient corridors are greater than in other rooms. The significance of this study is to understand the active infiltration of air to guide the design and operation of ventilation systems in infectious disease hospitals or building remodeled to isolate close contacts of COVID-19 patients. It is also instructive for the design of pressure gradients in clean workshops, biological laboratories, and other similar buildings.

Internal thermal insulation composite system (ITICS) can be an important measure for the energy-saving retrofitting of buildings. However, ITICS may cause harmful effects on the hygrothermal performance of building envelopes. This work investigated the influence of the materials' hygric properties on the hygrothermal performance of a typical ITICS in different climate conditions in China. Two base wall materials, the traditional concrete and a new type aerated concrete, were tested and compared for their hygric properties firstly. The influence of the hygroscopicity of exterior plasters, the permeability of insulation materials and the climate conditions were then analyzed with WUFI simulations. The hygrothermal performance was evaluated with consideration of the total water content (TWC) of the walls and the moisture flux strength, the relative humidity (RH) and the mould growth risk at the interface between the base wall and the insulation layer (B-I interface). The numerical analysis implies that the TWC of internal insulated walls depends mainly on the hygroscopicity of exterior plaster and the wind-driven rain intensity. The upper limits for the water absorption coefficient of exterior plasters used in Beijing, Shanghai and Fuzhou are 1e-9, 1e-10, 1e-10 m2/s respectively. When such limits are guaranteed, a vapour tight system created by using insulation materials with a large vapour resistance factor or adding a vapour barrier can improve the hygrothermal performance of ITICS, especially for concrete walls in cold climate.

Delicately designed metal–organic framework (MOF)-derived nanostructured electrocatalysts are essential for improving the reaction kinetics of the oxygen evolution reaction and tuning the selectivity of small organic molecule oxidation reactions. Herein, novel oxalate-modified hollow CoFe-based layered double hydroxide nanocages (h-CoFe-LDH NCs) and yolk–shell ZIF@CoFe-LDH nanocages (ys-ZIF@CoFe-LDH NCs) are developed through an etching–doping reconstruction strategy from a Co-based MOF precursor (ZIF-67). The distinctive nanostructures, along with the incorporation of the secondary metal element and intercalated oxalate groups, enable h-CoFe-LDH NCs and ys-ZIF@CoFe-LDH NCs to expose more active sites with high intrinsic activity. The resultant h-CoFe-LDH NCs exhibit outstanding OER activity with an overpotential of only 278 ​mV to deliver a current density of 50 ​mA ​cm−2. Additionally, controlling the reconstruction degree enables the formation of ys-ZIF@CoFe-LDH NCs with a yolk–shell nanocage nanostructure, which show outstanding electrocatalytic performance for the selective ethylene glycol oxidation reaction (EGOR) toward formate, with a Faradaic efficiency of up to 91%. Consequently, a hybrid water electrolysis system integrating the EGOR and the hydrogen evolution reaction using Pt/C||ys-ZIF@CoFe-LDH NCs is explored for energy-saving hydrogen production, requiring a cell voltage 127 ​mV lower than water electrolysis to achieve a current density of 50 ​mA ​cm−2. This work demonstrates a feasible way to design advanced MOF-derived electrocatalysts toward enhanced electrocatalytic reactions.

Transition metal-based single-atom catalysts (TM-SACs) are promising alternatives to Au- and Ag-based electrocatalysts for CO production through CO2 reduction reaction. However, developing TM-SACs with high activity and selectivity at low overpotentials is challenging. Herein, a novel Fe-based SAC with Si doping (Fe-N-C-Si) was prepared, which shows a record-high electrocatalytic performance toward the CO2-to-CO conversion with exceptional current density (>350.0 mA cm−2) and ~100% Faradaic efficiency (FE) at the overpotential of 90%) for CO production. Experimental combined with theoretical analysis unraveled that the nearby Si dopants in the form of Si-C/N bonds modulate the electronic structure of the atomic Fe sites in Fe-N-C-Si to markedly accelerate the key pathway involving *CO intermediate desorption, inhibiting the poisoning of the Fe sites under high CO coverage and thus boosting the CO2RR performance. This work provides an efficient strategy to tune the adsorption/desorption behaviors of intermediates on single-atom sites to improve their electrocatalytic performance.

Tunnels play a vital role in enhancing traffic flow and supporting public transportation systems. However, the discharge of polluted air and waste heat from vehicles passing through tunnels significantly raises the temperature inside, presenting challenges in terms of occupant comfort, tunnel safety, and infrastructure integrity. Therefore, ensuring proper temperature control is essential for their efficient operation. This study aims to investigate the phenomenon of temperature rise in ultra-long tunnels during normal operations, as limited research has been conducted in this area. The Shanghai Yangtze River Tunnel serves as a case study, utilizing temperature and air velocity data collected throughout the year (2021) from the management company. The analysis reveals that the temperature distribution near the tunnel exit is influenced by outdoor temperature fluctuations and traffic volume. The highest temperatures occur on 25 August (39.74 °C) during peak traffic hours. On-site measurements of tunnel temperature, humidity, and air velocity during winter and summer seasons yield the following results. During winter, the air temperature and wall temperature inside the tunnel experience significant increases along its length. The air temperature rises by approximately 11 °C from the entrance to the exit, while the wall temperature increases by about 15 °C. In contrast, during summer, the air temperature only rises by 2.7 °C, and the wall temperature increases by around 3 °C. Consequently, the humidity decreases along the tunnel, and this decrease is correlated with the magnitude of temperature increase. Furthermore, measurements of air velocity indicate that natural and traffic-induced winds contribute to the overall airflow inside the tunnel. A temperature data logger installed in the tunnel recorded temperature changes during the period of pandemic lockdown and subsequent recovery, spanning the spring and summer seasons. During the lockdown period, there was a relatively small increase in temperature along the tunnel, suggesting that vehicle heat dissipation is the primary factor contributing to temperature rise inside. Additionally, a method is proposed to predict the cross-sectional temperature of the tunnel using measured air velocities.

The purpose of this paper is to investigate the fatigue properties of C17200 alloy under the condition of quenching aging heat treatment at high temperatures, and to provide a design reference for its application in a certain temperature range. For this purpose, the tensile and rotary bending fatigue (RBF) tests were carried out at different temperatures (25 °C, 150 °C, 350 °C, and 450 °C). The tensile strength was obtained, and relationships between the applied bending stress levels and the number of fatigue fracture cycles were fitted to the stress-life (S-N) curves, and the related equations were determined. The fractured surfaces were observed and analyzed by a scanning electron microscopy (SEM). The results show that the RBF fatigue performance of C17200 alloy specimens is decreased with the increase in test temperature. When the temperature is below 350 °C, the performance degradation amplitudes of mechanical properties and RBF fatigue resistance are at a low level. However, compared to the RBF fatigue strength of 1 × 107 cycles at 25 °C, it is decreased by 38.4% when the temperature reaches 450 °C. It is found that the fatigue failure type of C17200 alloy belongs to surface defect initiation. Below 350 °C, the surface roughness of the fatigue fracture is higher, which is similar to the brittle fracture, so the boundary of the fracture regions is not obvious. At 450 °C, due to the further increase in temperature, oxidation occurs on the fracture surface, and the boundary of typical fatigue zone is obvious.

In China’s typical high-density cities, in order to meet the residential needs, a Chinese characteristic and typical high-rise residence with multiple flats sharing one staircase has been created. Due to the Chinese cooking methods, such as frying and stir-frying, the middle flats’ kitchens of these high-rise residences are easily exposed to cooking pollutants, which endanger people’s health. As the outdoor transition space directly adjacent to the kitchens of the middle flats, the inner-courtyards in high-rise residences make the cooking pollutants easier to be diffused. Therefore, the inner-courtyard form has a significant impact on the ventilation and diffusion of cooking pollutants. In this study, with the method of measurement and CFD simulation, the relationship between cooking pollutants diffusion in the kitchens of the middle flats and the flow field in inner-courtyards was analyzed, and the impact of different inner-courtyard forms on cooking pollutants diffusion distribution in high-rise residential under natural ventilation was discussed. The results show that different inner-courtyard forms have different effects on the diffusion of cooking pollutants: the enclosed courtyards will greatly increase the cross-contamination between the kitchen and the adjacent space; increasing the openness of the courtyard will not enhance the diffusion level of pollutants, but has a negative effect; compared with centralized courtyards, symmetrical courtyards have a better echo with the kitchen in the layout, which is more conducive to the diffusion of cooking pollutants.