Unveiling the Effect of Magnetic Noise in the Coherence of Single-Molecule Quantum Processors

Quantum bits (qubits) constitute the most elementary building-blocks of any quantum technology, where information is stored and processed in the form of quantum superpositions between discrete energy levels. In particular, the fabrication of quantum processors is a key long-term goal that will allow us conducting specific tasks much more efficiently than the most powerful classical computers can do. Motivated by recent experiments in which three addressable spin qubits are defined on a potential single-molecule quantum processor, namely the [Gd(H2O)P5W30O110]12− polyoxometalate, we investigate the decohering effect of magnetic noise on the encoded quantum information. Our state-of-the-art model, which provides more accurate results than previous estimates, show a noticeable contribution of magnetic noise in limiting the survival timescale of the qubits. Yet, our results suggest that it might not be the only dephasing mechanism at play but other mechanisms, such as lattice vibrations and physical movement of magnetic nuclei, must be considered to understand the whole decoherence process

Field-Induced Slow Magnetic Relaxation In the First Dy(III)-centered 12-Metallacrown-4 Double-Decker

The reaction of Dy(O2CMe)3•xH2O and Ga(NO3)3•xH2O led to the isolation of (nBu4N)[GaIII8DyIII(OH)4(shi)8] (1). The compound possesses a unique chemical structure enclosing the central magnetic DyIII ion between diamagnetic GaIII-based metallacrown 12-MC-4 ligands. The double-decker complex exhibits field-induced single-molecule magnet (SMM) behaviour with an effective energy barrier (Ueff) of 39 K (27.1 cm-1). Consistent with the observed slow relaxation of magnetization, theoretical calculations suggest a ground state mainly determined by |±11/2> in the easy axis direction

Enhancing the capacity of oxygen carriers for selective oxidations through phase cooperation: Bismuth oxide and ceria-zirconia

Interfacing selective catalysts with oxygen carriers enhances capacity without affecting the surface chemistry, simplifying the design of selective oxygen carriers.</p

Tridimensional N, P-Codoped Carbon Sponges as Highly Selective Catalysts for Aerobic Oxidative Coupling of Benzylamine

[EN] Two tridimensional N-doped porous carbon sponges (3DC-X) have been prepared by using cetyltrimethylammonium chloride ( CTAC) and cetyltrimethylammonium bromide (CTAB) as soft templates and alginate to replicate the liquid crystals formed by CTA+ in water. Alginate is a filmogenic polysaccharide of natural origin having the ability to form nanometric defectless films around objects. Subsequent pyrolysis at 900 degrees C under an Ar flow of the resulting CTA(+)-polysaccharide assemblies result in 3DC-1 and 3DC-2, with the N percentages of 0.48 and 0.36 wt % for the materials resulting from CTAC and CTAB, respectively. Another four 3DC materials were obtained via pyrolysis of the adduct of phytic acid and chitosan, rendering an amorphous, N and P-codoped carbon sample (3DC-3 to 3DC-6). The six 3DC samples exhibit a large area (>650 m(2) x g(-1)) and porosity, as determined by Ar adsorption. The catalytic activity of these materials in promoting the aerobic oxidation of benzylamine increases with the specific surface area and doping, being the largest for 3DC-4, which is able to achieve 73% benzylamine conversion to N-benzylidene benzylamine in solventless conditions at 70 degrees C in 5 h. Quenching studies and hot filtration tests indicate that 3DC-4 acts as a heterogeneous catalyst rather than an initiator, triggering the formation of hydroperoxyl and hydroxyl radicals as the main reactive oxygen species involved in the aerobic oxidation.Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa 2016 and RTI2018-890237-CO2-R1) and Generalitat Valenciana is gratefully acknowledged. A.P. thanks the Spanish Ministry for a Ramon y Cajal Research associate contract. A.D. is thankful to the University Grants Commission, New Dekhi, for awarding Assistant Professorship through the Faculty Recharge Programme.Peng, L.; Garcia-Baldovi, H.; Dhakshinamoorthy, A.; Primo Arnau, AM.; García Gómez, H. (2022). Tridimensional N, P-Codoped Carbon Sponges as Highly Selective Catalysts for Aerobic Oxidative Coupling of Benzylamine. ACS Omega. 7(13):11092-11100. https://doi.org/10.1021/acsomega.1c07179110921110071

Photocatalytic Hydrogen Production from Glycerol Aqueous Solutions as Sustainable Feedstocks Using Zr-Based UiO-66 Materials under Simulated Sunlight Irradiation

[EN] There is an increasing interest in developing cost-effective technologies to produce hydrogen from sustainable resources. Herein we show a comprehensive study on the use of metal-organic frameworks (MOFs) as heterogeneous photocatalysts for H-2 generation from photoreforming of glycerol aqueous solutions under simulated sunlight irradiation. The list of materials employed in this study include some of the benchmark Zr-MOFs such as UiO-66(Zr)-X (X: H, NO2, NH2) as well as MIL-125(Ti)-NH2 as the reference Ti-MOF. Among these solids, UiO-66(Zr)-NH2 exhibits the highest photocatalytic H-2 production, and this observation is attributed to its adequate energy level. The photocatalytic activity of UiO-66(Zr)-NH2 can be increased by deposition of small Pt NPs as the reference noble metal co-catalyst within the MOF network. This photocatalyst is effectively used for H-2 generation at least for 70 h without loss of activity. The crystallinity of MOF and Pt particle size were maintained as revealed by powder X-ray diffraction and transmission electron microscopy measurements, respectively. Evidence in support of the occurrence of photoinduced charge separation with Pt@UiO-66(Zr)-NH2 is provided from transient absorption and photoluminescence spectroscopies together with photocurrent measurements. This study exemplifies the possibility of using MOFs as photocatalysts for the solar-driven H-2 generation using sustainable feedstocks.Y S.N. is gracious for the financial support from the Agencia Valenciana de la Innovacio (AVI, INNEST/2020/111) project and Grant PID2021-123856OB-I00 fundedby MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe".Rueda-Navarro, CM.; Ferrer Ribera, RB.; Garcia-Baldovi, H.; Navalón Oltra, S. (2022). Photocatalytic Hydrogen Production from Glycerol Aqueous Solutions as Sustainable Feedstocks Using Zr-Based UiO-66 Materials under Simulated Sunlight Irradiation. Nanomaterials. 12(21):1-17. https://doi.org/10.3390/nano12213808117122

Photocatalytic Water Splitting Promoted by 2D and 3D Porphyrin Covalent Organic Polymers Synthesized by Suzuki-Miyaura Carbon-Carbon Coupling

[EN] This work deals with the synthesis of metal-free and porphyrin-based covalent organic polymers (COPs) by the Suzuki-Miyaura coupling carbon-carbon bond forming reaction to study the photocatalytic overall water splitting performance. Apart from using 5,10,15,20-Tetrakis-(4-bromophenyl)porphyrin, we have chosen different cross-linker monomers to induce 2-dimensional (2D) or 3-dimensional (3D) and different rigidity in their resulting polymeric molecular structure. The synthesised COPs were extensively characterised to reveal that the dimensionality and flexibility of the molecular structure play an intense role in the physical, photochemical, and electronic properties of the polymers. Photoinduced excited state of the COPs was evaluated by nanosecond time-resolved laser transient absorption spectroscopy (TAS) by analysing excited state kinetics and quenching experiments, photocurrent density measurements and photocatalytic deposition of Ru3+ to RuO2, and photocatalysis. In summary, TAS experiments demonstrated that the transient excited state of these polymers has two decay kinetics and exhibit strong interaction with water molecules. Moreover, photocurrent and photocatalytic deposition experiments proved that charges are photoinduced and are found across the COP molecular network, but more important charges can migrate from the surface of the COP to the medium. Among the various COPs tested, COP-3 that has a flexible and 3D molecular structure reached the best photocatalytic performances, achieving a photocatalytic yield of 0.4 mmol H-2 x g(COP-3)(-1) after 3 h irradiation.Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa with grant code RTI2018-098237-CO21), Generalitat Valenciana (Prometeo 2017/083) and European Union [APOSTD2018/216] are gratefully acknowledged.Nóvoa-Cid, M.; Melillo, A.; Ferrer Ribera, RB.; Alvaro Rodríguez, MM.; Garcia-Baldovi, H. (2022). Photocatalytic Water Splitting Promoted by 2D and 3D Porphyrin Covalent Organic Polymers Synthesized by Suzuki-Miyaura Carbon-Carbon Coupling. Nanomaterials. 12(18):1-19. https://doi.org/10.3390/nano12183197119121

Plasma production of nanomaterials for energy storage: continuous gas-phase synthesis of metal oxide CNT materials via a microwave plasma.

In this work we show for the first time that a continuous plasma process can synthesize materials from bulk industrial powders to produce hierarchical structures for energy storage applications. The plasma production process's unique advantages are that it is fast, inexpensive, and scalable due to its high energy density that enables low-cost precursors. The synthesized hierarchical material is comprised of iron oxide and aluminum oxide aggregate particles and carbon nanotubes grown in situ from the iron particles. New aerosol-based methods were used for the first time on a battery material to characterize aggregate and primary particle morphologies, while showing good agreement with observations from TEM measurements. As an anode for lithium ion batteries, a reversible capacity of 870 mA h g-1 based on metal oxide mass was observed and the material showed good recovery from high rate cycling. The high rate of material synthesis (∼10 s residence time) enables this plasma hierarchical material synthesis platform to be optimized as a means for energetic material production for the global energy storage material supply chain

Gas-Phase Photochemical Overall H2 S Splitting by UV Light Irradiation

[EN] Splitting of hydrogen sulfide is achieved to produce valueadded chemicals. Upon irradiation at 254 nm in the gas phase and in the absence of catalysts or photocatalysts at near room temperature, H2S splits into stoichiometric amounts of H2 and S with a quantum efficiency close to 50%. No influence of the presence of CH4 and CO2 (typical components in natural gas and biogas in which H2S is an unwanted component) on the efficiency of overall H2S splitting was observed. A mechanism for the H2 and S formation is proposed.Financial support by the Spanish Ministry of Economy and R1) and Generalitat Valenciana (Prometeo 2013-014) is gratefully acknowledged. Thanks are due to Dr. J. A. Agullo-Macia for performing a preliminary experiment.Garcia-Baldovi, H.; Albero-Sancho, J.; Ferrer Ribera, RB.; Mateo-Mateo, D.; Alvaro Rodríguez, MM.; García Gómez, H. (2017). Gas-Phase Photochemical Overall H2 S Splitting by UV Light Irradiation. ChemSusChem. 10(9):1996-2000. https://doi.org/10.1002/cssc.201700294S1996200010