MoS2 has emerged as a good application prospect in the electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the catalytic activity of MoS2 is greatly restricted by its inferior electrical conductivity, inadequate exposure of active edge sites, and sluggish water dissociation dynamics. Herein, a 1D/2D heteronanostructure composed of SiC nanowires wrapped with MoS2 nanosheets was prepared via the hydrothermal synthesis of MoS2 on highly connected SiC nanowires (SiCnw). The nanocomposites exhibit an emerging tectorum-like morphology with interface connections of C–Mo bonds, which benefit the efficient interfacial transmission of electrons. Due to the synergetic catalytic effects of MoS2 nanosheets and SiC nanowires, the MoS2/SiCnw nanocomposites possess efficient catalytic performance with a low Tafel slope (55 mV/dec). SiC nanocrystals could reduce the activated water dissociation energy barrier, and the morphologies of connected nanowires could improve the active site exposure and charge transport. The nanocomposites possess favorable hydrogen adsorption free energy from density functional theory (DFT) calculations. The electrocatalytic performance of MoS2/SiCnw nanocomposites could be further improved by assembling the nanocomposites on a carbon fiber paper to enhance the electronic transmission efficiency.

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Particulate matter (PM), a complex mixture of small particles and liquid droplets floating in air, is a consequence of severe air pollution. [1][2][3] PM is usually classified as PM 2.5 and PM 10 , referring to particle sizes less than 2.5 µm and between 2.5 and 10 µm, respectively. The smaller the PM, the more hazardous it becomes because it can penetrate into human lungs and bronchi, causing many respiratory diseases, including cancer. [4][5][6][7][8] Nowadays, PM has become a cosmopolitan environmental crisis, especially in developing countries. Therefore, managing and reducing PM pollution is urgently needed. [9,10] Particulate matter (PM) is one of the most severe air pollutants and poses a threat to human health. Air filters with high filtration efficiency applied to the source of PM are an effective way to reduce pollution. However, many of the present filtration materials usually fail because of their high pressure drop under high-velocity airflow and poor thermal stability at high temperatures. Herein, a highly porous Si 3 N 4 nanofiber sponge (Si 3 N 4 NFS) assembled by aligned and well-interconnected Si 3 N 4 nanofibers is designed and fabricated via chemical vapor deposition (CVD). The resulting ultralight Si 3 N 4 NFS (2.69 mg cm −3 ) processes temperature-invariant reversible strechability (10% strain) and compressibility (50% strain), which enables its mechanical robustness under high-velocity airflow. The highly porous and aligned microstructure result in a Si 3 N 4 NFS with high filtration efficiency for PM 2.5 (99.97%) and simultaneous low pressure drop (340 Pa, only <0.33% of atmospheric pressure) even under a high gas flow velocity (8.72 m s −1 ) at a high temperature (1000 °C). Furthermore, the Si 3 N 4 NFS air filter exhibits good long-term service ability and recyclability. Such Si 3 N 4 NFS with aligned microstructures for highly efficient gas filters provides new perspectives for the design and preparation of high-performance filtration materials.Air filters applied at the source of PM are thought to be an effective way to reduce air pollution. [11,12] Usually, there are two types of air filters. One is a porous membrane air filter, which usually has small pores to capture PMs. However, once PMs deposit and block the pores, the pressure drop becomes large, and the filter fails. [13] The other is a fibrous air filter, which exhibits a highly porous microstructure that is assembled by micrometer-sized fibers or nanofibers and captures PMs via a series of mechanisms such as physical interception, adhesion, and electrostatic interaction. [14][15][16] Compared with micrometer-sized fibrous air filters, nanofiber-based filters have higher PM trapping efficiency owing to their smaller pores and higher porosity. Nanofibrous air filters also have a low pressure drop because of the similar size of the nanofiber diameter and the average path of air molecules. [11] Ceramic fibrous air filters have recently gained increased attention owing to their prominent chemical and physical stabilities and high-...

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