Structural and Functional Behaviour of Ce-Doped Wide-Bandgap Semiconductors for Photo-Catalytic Applications

Increasing the photocatalytic efficiency of earth-abundant wide-bandgap semiconductors is of high interest for the development of cheap but effective light-driven chemical conversion processes. In this study, the coupling of ZnO and TiO2 with low contents of the rare-earth Ce species aimed to assess the photo-catalytic performance of the two semiconductors (SC). Structural and optical characterizations were performed to estimate the effect of the different interactions between Zn2+, Ti4+ and Ce4+ ions, and how the photo-responsive behaviour of Ce-Ti and Ce-Zn composites was affected. Therefore, photo-catalytic tests were performed for all Ce-modified SC to assess both their photo-oxidative and photo-reductive properties. Amongst all the tested materials, only Zn-based samples resulted in being suitable for the photo-oxidation of the methylene blue (MB) organic pollutant in a synthetic-dependent fashion

Materiali Nanostrutturati per la Foto-conversione di CO2

Tra i tentativi per controllare il livello di gas serra (GS), come, per esempio, la quantità di biossido di carbonio (CO2 ) nell’atmosfera, vi è l’utilizzo di tecnologie finalizzate a cattura e utilizzo del carbonio (CUC). Nello studio descritto, l’ossido di zinco (ZnO) e l’ossido di titanio (TiO2 ) sono stati testati prima come candidati per la cattura di CO2 e sua conversione diretta mediata dal solo utilizzo della luce, poi per un processo di fotocatalisi elettro-assistito, mediante l’applicazione di un potenziale elettrico, nell’ottica di un processo di conversione più sostenibile ed economico rispetto alle tecnologie attualmente impiegate

Effect of the Synthetic Parameters over ZnO in the CO₂ Photoreduction

Zinc oxide (ZnO) is an attractive semiconductor material for photocatalytic applications, owing to its opto-electronic properties. Its performances are, however, strongly affected by the surface and opto-electronic properties (i.e., surface composition, facets and defects), in turn related to the synthesis conditions. The knowledge on how these properties can be tuned and how they are reflected on the photocatalytic performances (activity and stability) is thus essential to achieve an active and stable material. In this work, we studied how the annealing temperature (400 °C vs. 600 °C) and the addition of a promoter (titanium dioxide, TiO2) can affect the physico-chemical properties of ZnO materials, in particular surface and opto-electronic ones, prepared through a wet-chemistry method. Then, we explored the application of ZnO as a photocatalyst in CO2 photoreduction, an appealing light-to-fuel conversion process, with the aim to understand how the above-mentioned properties can affect the photocatalytic activity and selectivity. We eventually assessed the capability of ZnO to act as both photocatalyst and CO2 adsorber, thus allowing the exploitation of diluted CO2 sources as a carbon source

Investigation of process parameters for solar fuel production using earth-abundant materials

Photoreduction of CO2 to solar fuels and chemicals offers a sustainable method to produce net zero energy vectors. For large-scale applications, it is crucial to develop an improved understanding of the influence of reaction conditions on the design and optimisation of the photoreactor. The performance of CuO impregnated on BaTiO3 photocatalyst was investigated and compared to pristine BaTiO3, and CuO impregnated on commercial P25 (CuO/P25) and ZnO. The influence of irradiance, CO2 and H2O flow and partial pressure, and CO2/H2O ratio on the product yield and selectivity were examined. Using Design of Experiments and Computational Fluid Dynamic modelling, the optimised reaction conditions were irradiance of 125 mW cm−2, with a CO2 flow of 0.09 mL min−1, and water bubbler temperature of 25 °C. At these conditions, a 2 and 10-fold increase of CO and CH4 production, respectively, were obtained, compared to baseline conditions as well as exhibited the highest CO and CH4 production rate compared to previous reports. Among the earth-abundant photocatalysts, CuO/P25 had the highest quantum yield for CH4 (φCH4: 0.47), whilst CuO/BaTiO3 exhibited highest φCO (0.09) and stability for CO production. The under-performing of BaTiO3 and CuO/BaTiO3 was attributed to the presence of amorphous phase in BaTiO3. This work reveals that the combination of catalyst design, reaction engineering, and modelling can improve the efficiencies of CO2 photoreduction

4q12 translocations with GSX2 expression identify a CD7+ acute myeloid leukaemia subset

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Detection of Pneumocystis jirovecii and Aspergillus spp. DNa in bronchoalveolar lavage fluids by commercial real-time PCr assays: comparison with conventional diagnostic tests

The present study employed two commercial real-time PCR kits, MycAssay™ Pneumocystis (PJ-PCR) and MycAssay™ Aspergillus (ASP-PCR), for the search of fungal DNA on 44 bronchoalveolar lavage (BAL) fluids from patients at risk of invasive fungal disease. Operationally, on the basis of clinical diagnosis and according to the European Organization for Research and Treatment Cancer/Mycoses Study Group (EORTC/MSG) criteria, patients were clustered in 3 groups: a P. jirovecii pneumonia (PCP) group, an invasive aspergillosis (IA) group and a control (CTRL) group, consisting of 8, 10 and 24 patients, respectively. The results were compared to those obtained with conventional diagnostic assays, including BAL culture, galactomannan-ELISA (GM) and immunofluorescence (IF). The PJ-PCR assay returned a sensitivity and specificity of 100% and 94.4%, respectively. The ASP-PCR assay showed a sensitivity and specificity of 80% and 97.1%. When compared to the culture assay, the ASP-PCR showed enhanced sensitivity, and a good level of agreement (kappa = 0.63) was observed between ASP-PCR and GM assays. Overall, our data emphasize the diagnostic usefulness of the two commercial real-time PCR assays, especially in high-risk patients where timing is critical and a low fungal burden may hamper correct and prompt diagnosis by conventional tests

An anthropocene-framed transdisciplinary dialog at the chemistry-energy nexus

At the energy-chemistry nexus, key molecules include carbon dioxide (CO2), hydrogen (H2), methane (CH4), and ammonia (NH3). The position of these four molecules and that of the more general family of synthetic macromolecular polymer blends (found in plastics) were cross-analyzed with the Planetary Boundary framework, and as part of five scientific policy roadmaps for the energy transition. According to the scenarios considered, the use of some of these molecules will be drastically modified in the coming years. Ammonia, which is currently almost exclusively synthesized as feedstock for the fertilizer industry, is envisioned as a future carbon-free energy vector. ‘Green hydrogen’ is central to many projected decarbonized chemical processes. Carbon dioxide is forecast to shift from an unavoidable byproduct to a valuable feedstock for the production of carbon-based compounds. In this context, we believe that interdisciplinary elements from history, economics and anthropology are relevant to any attempted cross-analysis. Distinctive and crucial insights drawn from elements of humanities and social sciences have led us to formulate or re-raise open questions and possible blind-spots in main roadmaps, which were developed to guide, inter alia, chemical research toward the energy transition. We consider that these open questions are not sufficiently addressed in the academic arena around chemical research. Nevertheless, they are relevant to our understanding of the current planetary crisis, and to our capacity to properly assess the potential and limitations of chemical research addressing it. This academic perspective was written to share this understanding with the broader academic community. This work is intended not only as a call for a larger interdisciplinary method, to develop a sounder scientific approach to broader scenarios, but also – and perhaps mostly – as a call for the development of radically transdisciplinary routes of research. As scientists with different backgrounds, specialized in different disciplines and actively involved in contributing to shape solutions by means of our research, we bear ethical responsibility for the consequences of our acts, which often lead to consequences well beyond our discipline. Do our research and the knowledge it produces respond, perpetuate or even aggravate the problems encountered by society