2022 roadmap on low temperature electrochemical CO2 reduction

Electrochemical CO2 reduction (CO2R) is an attractive option for storing renewable electricity and for the sustainable production of valuable chemicals and fuels. In this roadmap, we review recent progress in fundamental understanding, catalyst development, and in engineering and scale-up. We discuss the outstanding challenges towards commercialization of electrochemical CO2R technology: energy efficiencies, selectivities, low current densities, and stability. We highlight the opportunities in establishing rigorous standards for benchmarking performance, advances in in operando characterization, the discovery of new materials towards high value products, the investigation of phenomena across multiple-length scales and the application of data science towards doing so. We hope that this collective perspective sparks new research activities that ultimately bring us a step closer towards establishing a low- or zero-emission carbon cycle.Catalysis and Surface Chemistr

VOCs Photocatalytic Degradation By Oxidic Materials In Films. Achieving Enhanced Activity By Creating Heterostructures

In this work, different photoactive oxides (both binary and ternary) were synthesized and deposited as films, both singularly and as composites and photocatalytically tested towards the degradation of volatile organic compounds (VOCs) in the gas phase. In particular, TiO2 and WO3 were selected as binary oxides, while copper vanadate (Cu2V2O7) was chosen as the ternary visible light active oxide. Colloidal syntheses performed under nitrogen pressure on Schlenk ramp were adopted to obtain both WO3 and Cu2V2O7 materials. The effects provided by the creation of heterojunctions on the final photocatalytic performance are investigated

Assembly of β-Cu2V2O7/WO3 heterostructured nanocomposites and the impact of their composition on structure and photoelectrochemical properties

Multinary metal oxides and their heterostructures play a key role as light absorbers in the production of solar chemicals. Synthetic tunability is crucial to understand the impact of composition and structure on the photoelectrochemical performance. Here, we assemble \u3b2-Cu2V2O7/WO3 heterostructured nanocomposites using a novel seeded-growth approach which allows an unprecedented compositional tunability. A 10 fold increase in the net photocurrent density towards sulfite oxidation was measured for the nanocomposite with the lowest loading of WO3 (\u3b2-Cu2V2O7\u2006:\u2006WO3 = 1\u2006:\u20060.1) as compared to the bare \u3b2-Cu2V2O7 counterpart. This improvement is attributed to the formation of an intimate junction between the two metal oxides which favors charge transfer and separation. An increase in the WO3 content results in the formation of macroscopic phase segregated domains which reduce these interfacial areas, thus degrading the phototoelectrochemical performance of the nanocomposites. While highlighting the effectiveness of heterostructuring and the importance of compositional tunability, this study points at the emerging need of techniques to control and to probe the intrinsic inhomogeneity of these complex inorganic heterojunctions

Tunneling Magnetoresistance with Sign Inversion in Junctions Based on Iron Oxide Nanocrystal Superlattices

Magnetic tunnel junctions sandwiching a superlattice thin film of iron oxide nanocrystals (NCs) have been investigated. The transport was found to be controlled by Coulomb blockade and single-electron tunneling, already at room temperature. A good correlation was identified to hold between the tunnel magnetoresistance (TMR), the expected magnetic properties of the NC arrays, the charging energies evaluated from current−voltage curves, and the temperature dependence of the junction resistance. Notably, for the first time, a switching from negative to positive TMR was observed across the Verwey transition, with a strong enhancement of TMR at low temperatures

Spin filter effect in iron oxide nanocrystal arrays

Integrating nanocrystals (NCs) into magnetic tunnel structures is of considerable interest due to expectation of novel properties from their spin selective transport and single electron features. Superstructures by cplloidal NCs having translational and orientational order and interesting collective magnetic properties can be prepared by solution casting through sensitive interparticle and particle-substrate interactions. In this work, we discuss the study on magnetic field induced assembly of mono-dispersed iron oxide NCs to obtain spin filter effect across (he superlattice array, when sandwiched between gold electrodes. The deposition of mixed phase Fe3O4@gamma-Fe2O3 NCs on SiO2/Au surface proceeds through slow solvent evaporation and are studied for controlled interparticle spacing. For specific NC concentration, the ordering depends on the substrate chemistry and the ligands passivating NC surface, which affects the concentration of cluster nuclei formed. In presence of a magnetic field, the tunnel structure exhibits enhanced positive tunnel magnetoresistance at low temperatures, which could be related to their ferromagnetism and the attempts by electrons to percolate NC superlattice with preserved spin. A sign reversal for magnetoresistance is exhibited by the vertical tunnel junctions on raising the temperature

Evaluation of Defects in Multilayer Carbon Fibre Epoxy for Aeronautics Applications

Production of carbon fibre reinforced polymers is an elaborate process unfree from faults and problems. Problems during the manufacturing, such as plies' overlapping, can cause flaws in the resulting material, so compromising its integrity. Compared with metallic materials, carbon epoxy composites show a number of advantages. Within this framework, ultrasonic tests are effective to identify the presence of defects. In this paper a Finite Element Method approach is proposed for evaluating the most effective incidence angle of an ultrasonic probe with regard to defects' identification. According to our goal, the analysis has been carried out considering a single-line plane emitting source varying the probe angle of inclination. The proposed model looks promising to specially emphasize the presence of delaminations as well as massive breaking in a specimen of multilayer carbon fibre epoxy. Subsequently, simulation parameters and results have been exploited and compared, respectively, for a preliminary experimental in-lab campaign of measurements with encouraging results