Zn+-O- Dual-Spin Surface State Formation by Modification of ZnO Nanoparticles with Diboron Compounds

One-Step Low-Temperature Synthesis of Metastable ε-Iron Carbide Nanoparticles with Unique Catalytic Properties Beyond Conventional Iron Catalysts

ε-Iron carbide has garnered increasing interest for its superior magnetic characteristics and catalytic performance compared to other iron carbides. However, its metastable nature has posed significant challenges for synthesis, often requiring ultrahigh pressure, multistep processes, complex reaction condition control, and highly toxic reagents. Consequently, the properties of ε-iron carbide remain largely unexplored. A simplified synthesis method for ε-iron carbide can accelerate the exploration of new functionalities. In this study, a novel one-step selective synthesis method for ε-iron carbide nanoparticles under mild conditions via a wet-chemical approach is presented. In this method, Fe3(CO)12, cetyltrimethylammonium bromide (CTAB), and bis(pinacolato)diboron (B2pin2) are added to hexadecylamine and reacted at 220 °C-a simple process that eliminates the need for extreme pressures and toxic substances. Detailed investigations elucidate the crucial roles of CTAB and B2pin2 in facilitating the selective formation of ε-iron carbide. This accessible and efficient synthesis process for ε-iron carbide can further enable the discovery of unprecedented catalytic properties in the reductive amination of benzaldehyde, distinct from those of conventional iron nanoparticle catalysts. Density functional theory calculations reveal insights into the electronic states responsible for the distinct activity of the ε-iron carbide nanoparticles.

Thermally treated zeolitic imidazolate framework-8 (ZIF-8) for visible light photocatalytic degradation of gaseous formaldehyde

The development of wide-spectrum responsive photocatalysts for efficient formaldehyde (HCHO) removal is highly desired yet remains a great challenge. Here we successfully converted zeolitic imidazolate framework-8 (ZIF-8), one of the most well-studied metal-organic frameworks (MOFs), from routine ultraviolet-driven to novel broad-spectrum-driven photocatalyst via a facile thermal treatment. The isocyanate groups (-N[double bond, length as m-dash]C[double bond, length as m-dash]O) formed in the thermally treated ZIF-8 (ZIF-8-T) is crucial in enabling the superior photocatalytic performance in formaldehyde degradation. Specifically, the best-performing ZIF-8-T sample showed around 2.1 and 9.4 times the HCHO adsorption amount and the solar photocatalytic degradation rate, respectively, of pristine ZIF-8. In addition, ZIF-8-T exhibited visible light (λ ≥ 400 nm) photocatalytic HCHO degradation performance, photo-converting 72% and nearly 100% of 20 ppm and 10 ppm HCHO within 1 hour, respectively. This work affords new insights and knowledge that inspire and inform the design and development of MOF-based photocatalysts with broad-spectrum responses for efficient air purification operations.