Matteo Compagnoni

Flame-pyrolysis-prepared catalysts for the steam reforming of ethanol

An innovative flame pyrolysis method was employed for the preparation of Ni-based catalysts for the steam reforming of ethanol. Titania and lanthana supports, characterised by variable acidity and Ni loading, were compared as well as the different procedures to add the Ni active phase to the support, thus affecting the metal dispersion. Samples characterisation provided evidence that the one-pot preparation of the catalyst by flame pyrolysis (FP) resulted in the formation of a mixed oxide phase and, thus, in a higher Ni dispersion, even at the highest loading. The metal–support interaction was also strengthened when preparing the samples by FP rather than by conventional impregnation. Steam reforming at 750 °C resulted in full ethanol conversion without by-products, such that a fuel processor able to feed a 5 kWe + 5 kWt fuel cell may operate with ca. 1.35 kg of catalyst. Tests at lower temperature were also carried out, focusing on the optimization of the resistance to coking. The best results at 500 °C were achieved for the FP-prepared sample supported over La2O3 and containing 15 wt% Ni as the active phase.

Bimetallic Ni–Cu Catalysts for the Low-Temperature Ethanol Steam Reforming: Importance of Metal–Support Interactions

The activity of bimetallic Ni–Cu catalysts in ethanol steam reforming was evaluated and compared to the activity of the corresponding monometallic Ni catalyst. Copper addition positively affected the catalytic activity only if the proper metal–support interactions, as well as the proper ratio between the different reducible species, were maintained. This target can be pursued by tuning the synthesis conditions.Graphical Abstract.

Metal Dispersion and Interaction with the Supports in the Coke Production Over Ethanol Steam Reforming Catalysts

Two families of Ni/TiO2 catalysts were prepared for use in the steam reforming of ethanol. The catalytic performances, in terms of both H2 productivity and stability towards coking and sintering, were related to the physico-chemical properties of the catalysts.

Spectroscopic investigation of Titania-supported gold nanoparticles prepared by a modified deposition/precipitation method for the oxidation of CO

The spectroscopic characterization of a material is a fundamental tool for understanding the structure–activity correlation for catalytic purposes. Regarding supported nanoparticles, this perspective has acquired more relevance in recent years and several techniques have been employed. In this work diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), coupled with CO adsorption, was used to investigate a modified deposition/precipitation method (DP‐UC) for the preparation of supported gold nanoparticles with very low metal loading (0.1–0.5 wt %). This promising synthetic route involves the use of urea as basic agent and NaBH4 as chemical reductant in contrast to the traditional high‐temperature reduction step. The systematic IR spectroscopic study of the Au loading was combined with CO oxidation catalytic tests. The evaluation of the results was also supported by several other techniques, such as X‐ray photoelectron spectroscopy, N2 physisorption, and transmission electron microscopy. Particular attention was given to the evaluation of the gold electronic state, surface dispersion, particle size, and the corresponding structure–activity relationship.

Kinetic modeling and reactor simulation for ethanol steam reforming

An extended kinetic model has been proposed for the ethanol steam reforming reaction that includes kinetic steps for the formation of important byproducts such as ethylene, acetaldehyde, and coke. The model has been applied to the regression of new kinetic data obtained with the use of a 9 wt % K2O/10 wt % Ni/ZrO2 catalyst prepared by flame pyrolysis. The kinetic tests were performed by varying the temperature, space velocity, and the water/ethanol ratio according to a central composite experimental design. The model was validated against literature data collected over a different catalytic system and without the presence of the selected byproducts to check its versatility and robustness. The model gave very straightforward predictions of catalyst performance for the literature data: in this case the lump sum of all the square residues (calculated vs. tabulated mol fractions) is 2.88×10−2 over a dataset of 408 points. For our own kinetic data, the model interpreted the conversion of ethanol and the evolution of the main byproducts, which include ethylene and acetaldehyde, correctly. The evolution of coke was interpreted less satisfactorily because of a missing step for coke gasification. Rate‐limiting steps have been identified together with very rapid reaction steps, which can be considered to be substantially equilibrated.

Protective effects of antihypertensive treatment in patients aged 85 years or older

Objective: To assess whether in individuals aged 85 years or older, adherence to antihypertensive drugs is accompanied by a reduced risk of cardiovascular events. Methods: A nested case–control study was carried out on a cohort of patients aged 85 years or older, who were newly treated with antihypertensive drugs between 2007 and 2009, using the database available for all citizens (about 10 million) of Lombardy (Italy). Cases were the cohort members who experienced death or hospital discharge for stroke, myocardial infarction (MI) or heart failure from the initial prescription until 2012. Up to five controls were randomly selected for each case. Logistic regression was used to model the outcome risk associated with the adherence with antihypertensive drug therapy. A patient cohort aged 70–84 years was taken for comparison. Results: Compared with patients with very low adherence, those aged 85 years or older (average 88 years) with high adherence showed a risk reduction for death (47%; 95% confidence interval, 5–57%) and all the outcomes combined (34%; 95% confidence interval, 21–45%). The risk of heart failure and stroke was also reduced, whereas the risk of MI was not affected by adherence with antihypertensive drugs. Similar findings were obtained in the cohort of patients aged 70–84 years. Conclusion: Adherence with antihypertensive drug therapy reduced the risk of cardiovascular morbidity in patients aged 85 years or more, the benefit including heart failure and stroke, although not MI, and extending to all-cause death.

Innovative photoreactors for unconventional photocatalytic processes: the photoreduction of CO2 and the photo-oxidation of ammonia

Solar energy, along with other renewable resources, is going to play a key role in waste treatments and CO2 conversion. Photocatalytic technologies can be considered an effective solution for these purposes. This work summarises the setup of two different reactor configurations for two challenging processes: nitrate/ammonia abatement from water and CO2 photoreduction. The project goal was the setup of proper photoreactors and the preliminary investigation of some critical operating process parameters. Concerning the CO2 photoreduction, large efforts have been devoted to study an innovative high-pressure reactor developed properly to overcome the main limitation of the reaction, i.e. the limited solubility of carbon dioxide in water. On the other hand, nitrate and ammonia conversion was investigated, exploring the reactor setup and the analysis of critical products such as nitrogen.

Mature versus emerging technologies for CO 2 capture in power plants: Key open issues in post-combustion amine scrubbing and in chemical looping combustion

Carbon capture and storage (CCS) have acquired an increasing importance in the debate on global warming as a mean to decrease the environmental impact of energy conversion technologies, by capturing the CO2 produced from the use of fossil fuels in electricity generation and industrial processes. In this respect, post-combustion systems have received great attention as a possible near-term CO2 capture technology that can be retrofitted to existing power plants. This capture technology is, however, energy-intensive and results in large equipment sizes because of the large volumes of the flue gas to be treated. To cope with the demerits of other CCS technologies, the chemical looping combustion (CLC) process has been recently considered as a solution for CO2 separation. It is typically referred to as a technology without energy penalty. Indeed, in CLC the fuel and the combustion air are never mixed and the gases from the oxidation of the fuel (i.e., CO2 and H2O) leave the system as a separate stream and can be separated by condensation of H2O without any loss of energy. The key issue for the CLC process is to find a suitable oxygen carrier, which provides the fuel with the activated oxygen needed for combustion. The aim of this work is to explore the feasibility of using perovskites as oxygen carriers in CLC and to consider the possible advantages with respect to the scrubbing process with amines, a mature post-combustion technology for CO2 separation.

Development of unconventional photocatalytic reactors and processes for the abatement of harmful N-containing pollutants

Development of Unconventional Photocatalytic Reactors and Processes for the Abatement of Harmful N-containing Pollutants Ilenia Rossetti, Matteo Compagnoni, Gianguido Ramis, Francesca Freyria, Marco Armandi, Barbara Bonelli a Dip. Chimica, Università degli Studi di Milano and INSTM Unit Milano-Università, Milan, Italy b Dip. Ing. Chimica, Civile ed Ambientale, Università degli Studi di Genova and INSTM Unit Genova, Genoa, Italy c Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico, Politecnico di Torino, Turin, Italy ilenia.rossetti@unimi.it

CO2photoconversion to fuels under highpressure: effect of TiO2phase and ofunconventional reaction conditions

Artificial photosynthesis is an up to date topic for the fixation of CO2 in form of valuable fuels. Recently, we set up an innovative concept of photoreactor to be applied to CO2 photoreduction, enabling operation up to 20 bar. This allows to improve CO2 solubility and to explore unconventional operating conditions for this very challenging reaction. Following a preliminary communication, to demonstrate the validity of the approach systematic testing has been here carried out on different TiO2 photocatalysts (anatase, rutile and anatase + rutile) doped with 0.1 wt% Au, by tuning pressure, temperature and pH. The operating conditions have been selected to maximise the production of gas phase products, i.e. CH4 + H2, with respect to liquid phase organic compounds. The present results overperform many of the recent achievements reported in the literature and throw the basis for a further optimisation of the photocatalytic material and of the photoreactor.