Pt/N–TiO2 Aerogel Composites Used for Hydrogen Production Via Photocatalysis Process

Sustainable catalysts for efficient triazole synthesis: an immobilized triazine-based copper-NNN pincer complex on TiO2

The multistep synthesis of a hybrid material based on a TiO2 core with an immobilized triazine-based copper(II)-NNN pincer complex is reported. The formation of the material was confirmed by FT-IR spectroscopy and elemental and thermogravimetric analyses, and the loading by copper ions was quantified by ICP/OES analysis. The properties of the hybrid material were further investigated by X-ray photoelectron spectroscopy (XPS), contiuous wave electron spin resonance (CW-ESR), UV-vis spectroscopy, and argon sorption. Efficient and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles was achieved by employing the hybrid material as a catalyst in a mixture of H2O/EtOH as a green solvent with excellent catalytic activity with a TOF up to 495 h-1 at 50 °C. The reusability of the prepared hybrid material in the catalytic reaction was possible over five consecutive runs without significant loss of catalytic activity. The described method represents an effective way to ensure sustainable use of pincer complexes in catalytic systems by immobilizing them on solid supports, resulting in a hybrid organic-inorganic catalyst platform.

Gas-Phase Nitrogen Doping of Monolithic TiO2 Nanoparticle-Based Aerogels for Efficient Visible Light-Driven Photocatalytic H2 Production

The development of visible light-active photocatalysts is essential for increasing the conversion efficiency of solar energy into hydrogen (H₂). Here, we present a facile method for nitrogen doping of monolithic titanium dioxide (TiO₂) nanoparticle-based aerogels to activate them for visible light. Plasma-enhanced chemical vapor deposition at low temperature enables efficient incorporation of nitrogen into preformed TiO₂ aerogels without compromising their advantageous intrinsic characteristics such as large surface area, extensive porosity, and nanoscale properties of the semiconducting building blocks. By balancing the dopant concentration and the defects, the nitridation improves optical absorption and charge separation efficiency. The nitrogen-doped TiO₂ nanoparticle-based aerogels loaded with palladium (Pd) nanoparticles show a significant enhancement in visible light-driven photocatalytic H₂ production (3.1 mmol h^-1 g^-1) with excellent stability over 5 days. With this method, we introduce a powerful tool to tune the properties of nanoparticle-based aerogels after synthesis for a specific application, as exemplified by visible light-driven H₂ production.

Origin of photocatalytic activity enhancement in Pd/Pt-deposited anatase N-TiO2- experimental insights and DFT study of the (001) surface

In pursuit of the ideal photocatalyst, cheap and stable semiconductor TiO₂ is considered to be a good choice if one is able to reduce its band gap and decrease the recombination rate of charge carriers. The approach that offers such improvements for energy conversion applications is the modification of TiO₂ with nitrogen and noble metals. However, the origin of these improvements and possibilities for further design of single-atom catalysts are not always straightforward. To shed light on the atomic-scale picture, we modeled the nitrogen-doped (001) anatase TiO₂ surface as a support for palladium and platinum single-atom deposition. The thermodynamics of various synthesis routes for Pd/Pt deposition and nitrogen doping is considered based on density functional theory (DFT)-calculated energies, highlighting the effect of nitrogen doping on metal dimer formation and metal-support interaction. XPS analysis of the valence band of the modified TiO₂ nanocrystals, and the calculated charge transfer and electronic structure of single-atom catalysts supported on the (001) anatase TiO₂ surface provide an insight into modifications occurring in the valence zone of TiO₂ due to nitrogen doping and Pd/Pt deposition at the surface. DFT results also show that substitutional nitrogen doping significantly increases metal-support interaction, while interstitial nitrogen doping promotes only Pt-support interaction.

One-pot photoassisted synthesis, in situ photocatalytic testing for hydrogen generation and the mechanism of binary nitrogen and copper promoted titanium dioxide

One-pot photosynthesis and in situ testing of binary codoped Cu(0)–N-TiO₂ yields hydrogen rate 675 μmol g⁻¹ h⁻¹; photoluminescence shows mechanism by excitation of N substitutional site.