Nanostructured Gd3+-TiO2 surfaces for self-cleaning application

Heterogeneous Trimetallic Nanoparticles as Catalysts

The development and application of trimetallic nanoparticles continues to accelerate rapidly as a result of advances in materials design, synthetic control, and reaction characterization. Following the technological successes of multicomponent materials in automotive exhausts and photovoltaics, synergistic effects are now accessible through the careful preparation of multielement particles, presenting exciting opportunities in the field of catalysis. In this review, we explore the methods currently used in the design, synthesis, analysis, and application of trimetallic nanoparticles across both the experimental and computational realms and provide a critical perspective on the emergent field of trimetallic nanocatalysts. Trimetallic nanoparticles are typically supported on high-surface-area metal oxides for catalytic applications, synthesized via preparative conditions that are comparable to those applied for mono- and bimetallic nanoparticles. However, controlled elemental segregation and subsequent characterization remain challenging because of the heterogeneous nature of the systems. The multielement composition exhibits beneficial synergy for important oxidation, dehydrogenation, and hydrogenation reactions; in some cases, this is realized through higher selectivity, while activity improvements are also observed. However, challenges related to identifying and harnessing influential characteristics for maximum productivity remain. Computation provides support for the experimental endeavors, for example in electrocatalysis, and a clear need is identified for the marriage of simulation, with respect to both combinatorial element screening and optimal reaction design, to experiment in order to maximize productivity from this nascent field. Clear challenges remain with respect to identifying, making, and applying trimetallic catalysts efficiently, but the foundations are now visible, and the outlook is strong for this exciting chemical field.

Preparation and characterization of photocatalytic Gd-doped TiO2 nanoparticles for water treatment

In recent years, the photocatalytic process by using TiO₂ nanoparticles (NPs) has produced a great interest in wastewater treatment due to its interesting features such as low-cost, environmental compatibility, and especially capacity to eliminate persistent organic compounds as well as microorganisms in water. In the present work, the photocatalytic activity of Gd-doped TiO₂ nanopowders, with different doping amount 0.1, 1, and 5 mol% synthesized by the sol-gel method, was studied under UV/Visible irradiation for water treatment application. The Gd-doped TiO₂ nanoparticles were investigated for their photocatalytic degradation of methylene blue (MB) dye and antibacterial activities against two bacterial strains namely Stenotrophomonas maltophilia (S. maltophilia) and Micrococcus luteus (M. luteus). MB dye was used as a pollutant model to estimate reactive oxygen species (ROS) generation and to correlate killing action of nanoparticles with the generation of ROS. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy were used to characterize the as-synthesized nanomaterials. Photocatalytic, as well as antibacterial tests, showed that doping with an appropriate amount of Gd could reduce the radiative recombination process of photogenerated electron-hole pairs in TiO₂ and induce a significant enhancement in photocatalytic and consequently antibacterial activity. The experimental sequence of bactericidal activity and photocatalytic degradation efficiency exhibited by the different gadolinium-doped nanoparticles was the following: 0.1 mol% Gd-doped TiO₂ > 1 mol% Gd-doped TiO₂ > 5 mol% Gd-doped TiO₂ > pure titania.

Difference in structural and chemical properties of sol–gel spin coated Al doped TiO2, Y doped TiO2 and Gd doped TiO2 based on trivalent dopants

Ti³⁺ state in metal doped TiO₂ based on lattice distortion that encouraged the formation of oxygen vacancy defects.