Scientific Papers in SCI

AgBr/NaTaO₃ composites, with different molar % of NaTaO₃ (Br/NTO(X%)), have been synthesized by simple precipitation methods; bare NaTaO₃ was synthesized by hydrothermal procedure, while AgBr was synthesized by a precipitation procedure using cetyl-tri-methyl-ammonium bromide (CTAB) and AgNO₃. Samples have been characterized by X-ray diffraction (XRD), N₂ adsorption, UV–vis diffuse reflectance spectroscopy (DRS), Fourier-transform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity of the as-prepared photo-catalysts was evaluated through photocatalytic degradation of rhodamine B (RhB), methyl orange (MO) and caffeic acid (CAFA) under UV and visible illumination. Single AgBr material and Br/NTO(X%) composites displayed the ability to absorb light in the visible region, while NaTaO₃ is only photoactive under UV irradiation. Based on the position of conduction and valence bands of AgBr and NaTaO₃, the heterojunction between these two photo-catalysts corresponds to a type II junction. In the case of photocatalytic degradation of RhB and CAFA, Br/NTO(x%) composites have highest photocatalytic activity than that obtained by both parental materials under the same operational conditions. AgBr and Br/NTO(x%) composites achieve a fast degradation of MO, together with a considerable adsorption capacity, attributed to the presence of a remaining amount of residual CTAB on the AgBr surface. In summary, coupling AgBr with NaTaO₃ improves the photocatalytic activity under both UV and visible illumination with respect to the parental components, but the performance of the composites is highly dependent on the type of substrate to be degraded and the illumination conditions.

Introduction: Innovating technologies to efficiently reduce carbon dioxide (CO2) emission or covert it into useful products has never been more crucial in light of the urgent need to transition to a net-zero economy by 2050. The design of efficient catalysts that can make the above a viable solution is of essence. Many noble metal catalysts already display high activity, but are usually expensive. Thus, alternative methods for their production are necessary to ensure more efficient use of noble metals.Methods: Exsolution has been shown to be an approach to produce strained nanoparticles, stable against agglomeration while displaying enhanced activity. Here we explore the effect of a low level of substitution of Ni into a Rh based A-site deficienttitanate aiming to investigate the formation of more efficient, low loading noblemetal catalysts.Results: We find that with the addition of Ni in a Rh based titanate exsolution is increased by up to similar to 4 times in terms of particle population which in turn results in up to 50% increase in its catalytic activity for CO2 conversion.Discussion: We show that this design principle not only fulfills a major research need in the conversion of CO2 but also provides a step-change advancement in the design and synthesis of tandem catalysts by the formation of distinct catalytically active sites.