Materials with Dirac point are so amazing since the charge carriers are massless and have an effective speed of light. Among the reported two-dimensional silicon allotropes, no one showing such exciting nature was proved experimentally. This fact motivates us to search for other such two-dimensional silicon allotropes. As a result, a new single atomic layer thin silicon allotrope was predicted by employing CALYPSO code in this work. This silicon allotrope is composed of eightmembered rings linked by Si-Si bonds and presents buckling formation. Expectedly, the electronic calculation reveals that there exists Dirac point at Fermi energy level. Furthermore, the ab initio molecular dynamics simulations displays that the original atomic configuration can be remained even at an extremely high temperature of 1000 K. We hope this work can expand the family of single atomic layer thin silicon allotropes with Dirac fermions.

Atomically dispersed metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low to avoid the formation of metal nanoparticles, making it difficult to improve the overall activity. Diverse strategies based on creating more anchoring sites (ASs) have been adopted to elevate the loading density. One problem of such traditional methods is that the single atoms always gather together before the saturation of all ASs. Here, a chemical scissors strategy is developed by selectively removing unwanted metallic materials after excessive loading. Different from traditional ways, the chemical scissors strategy places more emphasis on the accurate matching between the strength of etching agent and the bond energies of metal‐metal/metal‐substrate, thus enabling a higher loading up to 2.02 wt% even on bare substrate without any pre‐treatment (the bare substrate without any pre‐treatment generally only has a few ASs for single atom loading). It can be inferred that by combining with other traditional methods which can create more ASs, the loading could be further increased by saturating ASs. When used for CH3OH generation via photocatalytic CO2 reduction, the as‐made single‐atom catalyst exhibits impressive catalytic activity of 597.8 ± 144.6 µmol h−1 g−1 and selectivity of 81.3 ± 3.8%.

Low-dimensional Si-based semiconductors are unique materials that can both match well with the Si-based electronics and satisfy the demand of miniaturization in modern industry. Owing to the lack of such materials, many researchers put their efforts into this field. In this work, employing a swarm structure search method and density functional theory, we theoretically predict two-dimensional atomically thin mononitrides SiN and GeN, both of which present semiconducting nature. Furthermore study shows that SiN and GeN behave as indirect band gap semiconductors with the gap of 1.75 and 1.20 eV, respectively. The ab initio molecular dynamics calculation tells that both two mononitrides can exist stably even at extremely high temperature of 2000 K. Notably, electron mobilities are evaluated as ∼0.888×10 3 cm 2 V −1 s −1 and ∼0.413×10 3 cm 2 V −1 s −1 for SiN and GeN, respectively. The present work expands the family of low-dimensional Si-based semiconductors.

the sluggish kinetics of oxygen evolution reaction (OER) for water splitting still hinders the wide application of this technology. Ru-and Ir-based oxides are highly active catalysts for OER, nevertheless, the scarcity and cost of Ru and Ir largely constrains the broad deployment of hydrogen production utilities. [4][5][6] To this end, transition metal oxide (TMO) electrocatalysts have been extensively investigated due to their earth-abundant and outstanding OER performance. [7][8][9][10] It is remarkable that spinel oxides present stunning catalytic performance for OER in alkaline electrolytes, benefitting from the coexistence of tetrahedral (T d ) and octahedral (O h ) transition-metal cation sites in TMOs, whereas such a complex structure with multiple sites also brings a great challenge on precise identification toward active sites for OER. [11][12][13][14] The tailoring of catalytic active sites for spinel oxides is of importance on the design of highly efficient electrocatalysts for OER, but the active sites of spinel oxides for OER are still elusive. [11,[15][16][17][18] For example, it is reported that the high OER activity of ZnCo 2 O 4 relies on the amounts of Co 3+ on the O h sites. [19] However, on the contrary, it also has been found that the Zn 2+ at T d sites is contributed Magnetic field enhanced electrocatalysis has recently emerged as a promising strategy for the development of a viable and sustainable hydrogen economy via water oxidation. Generally, the effects of magnetic field enhanced electrocatalysis are complex including magnetothermal, magnetohydrodynamic and spin selectivity effects. However, the exploration of magnetic field effect on the structure regulation of electrocatalyst is still unclear whereas is also essential for underpinning the mechanism of magnetic enhancement on the electrocatalytic oxygen evolution reaction (OER) process. Here, it is identified that in a mixed NiFe 2 O 4 (NFO), a large magnetic field can force the Ni 2+ cations to migrate from the octahedral (O h ) sites to tetrahedral (T d ) sites. As a result, the magnetized NFO electrocatalyst (NFO-M) shows a two-fold higher current density than that of the pristine NFO in alkaline electrolytes. The OER enhancement of NFO is also observed at 1 T (NFO@1T) under an operando magnetic field. Our first-principles calculations further confirm the mechanism of magnetic field driven structure regulation and resultant OER enhancement. These findings provide a strategy of manipulating tetrahedral units of spinel oxides by a magnetic field on boosting OER performance.

The CO2 reduction reaction (CRR) represents a promising route for the clean utilization of renewable resources. But mass‐transfer limitations seriously hinder the forward step. Enhancing the surface hydrophobicity by using polymers has been proved to be one of the most efficient strategies. However, as macromolecular organics, polymers on the surface hinder the transfer of charge carriers from catalysts to reactants. Herein, we describe an in‐situ surface fluorination strategy to enhance the surface hydrophobicity of TiO2 without a barrier layer of organics, thus facilitating the mass transfer of CO2 to catalysts and charge transfer. With less obstruction to charge transfer, a higher CO2, and lower H+ surface concentration, the photocatalytic CRR generation rate of methanol (CH3OH) is greatly enhanced to up to 247.15 μmol g−1 h−1. Furthermore, we investigated the overall defects; enhancing the surface hydrophobicity of catalysts provides a general and reliable method to improve the competitiveness of CRR.