Enhanced Electrochemical Performance of Highly Porous CeO-Doped Zr Nanoparticles for Supercapacitor Applications.

The aim of this work was to develop an ultrasonic-assisted synthesis method for the fabrication of CeO-doped Zr nanoparticles that would improve the performance of supercapacitor electrodes. This method, which eliminates the need for high-temperature calcination, involves embedding CeO into Zr nanoparticles through 1 hr (CeO-Zr-1) and 2 hrs (CeO-Zr-2) of ultrasonic irradiation, resulting in the formation of nanostructures with significant improvements in their electrochemical properties. Through physicochemical analysis, we observed that the CeO-doped Zr nanoparticles, particularly those treated for 2 hrs (CeO-Zr-2), exhibit superior crystalline phase purity, optimal chemical surface composition, minimal agglomeration with particle sizes below 50 nm, and an impressive average surface area of 178 m/g.

An Opportunity for Synergizing Desalination by Membrane Distillation Assisted Reverse-Electrodialysis for Water/Energy Recovery.

Industry, agriculture, and a growing population all have a major impact on the scarcity of clean-water. Desalinating or purifying contaminated water for human use is crucial. The combination of thermal membrane systems can outperform conventional desalination with the help of synergistic management of the water-energy nexus.

Insights into the Engineered Gold Nanoparticle-Based Remedy for Supplementation Therapy of Ovarian Carcinoma.

Chronic diseases, notably cancer, pose a significant global threat to human life. Oncologists and medical professionals addressing malignancies confront challenges such as toxicity and multidrug resistance. To tackle these issues, the focus has shifted toward the employment of multifunctional colloidal gold nanoparticles.

Electrochemical Detection of 4-Nitrophenol Using a Novel SrTiO/Ag/rGO Composite.

In this study, an eco-friendly strategy was used to prepare a novel SrTiO/Ag/rGO composite. A SrTiO/Ag/rGO composite-modified screen-printed carbon electrode (SPCE) was applied for the electrochemical detection of 4-nitrophenol. A simple ultrasonic method with an ultrasonic frequency of 20 kHz was used for the synthesis of SrTiO/Ag/rGO composite material.

Structural and Electronic Effects at the Interface between Transition Metal Dichalcogenide Monolayers (MoS, WSe, and Their Lateral Heterojunctions) and Liquid Water.

Transition metal dichalcogenides (TMDCs) can be used as optical energy conversion materials to catalyze the water splitting reaction. A good catalytical performance requires: (i) well-matched semiconductor bandgaps and water redox potential for fluent energy transfer; and (ii) optimal orientation of the water molecules at the interface for kinetically fast chemical reactions. Interactions at the solid-liquid interface can have an important impact on these two factors; most theoretical studies have employed semiconductor-in-vacuum models.

DFT-based investigation of different properties for transition metal-doped germanium TMGe (TM = Ru, Rh; n = 1-20) clusters.

The geometries and energetic, electronic, and magnetic features of transition metal-doped germanium (TMGe with TM = Ru, Rh; n = 1-20) clusters are systematically studied by means of first principle computations on the basis of the density functional theory (DFT) approach. The doping TM atom largely participates to strengthen the Ge cluster stability by increasing the binding energies. A good stability is obtained for RuGe, RhGe, and RhGe clusters.

In silico design of novel NRR electrocatalysts: cobalt-molybdenum alloys.

Metals are amongst the most efficient developed electrocatalysts for nitrogen reduction reaction (NRR) with iron and ruthenium presenting the best catalytic indicators. However, the potential use of metal alloys as NRR electrocatalysts is still underdeveloped. While Co has demonstrated poor electrocatalytic activity for NRR, alloying Co with Mo exhibits an improvement in both N physisorption and the stabilisation of the elusive NH as the first reduced intermediate species.

Mechanistic Insight into the Photoredox-Nickel-HAT Triple Catalyzed Arylation and Alkylation of α-Amino C-H Bonds.

We report here a comprehensive computational analysis of the mechanisms of the photoredox-nickel-HAT (HAT: hydrogen atom transfer) catalyzed arylation and alkylation of α-amino C-H bonds developed by MacMillan and co-workers. Different alternatives for the three catalytic cycles were tested to identify unambiguously the operative reaction mechanism. Our analysis indicated that the Ir photoredox catalyst, upon irradiation with visible light, can be either reduced or oxidized by the HAT and nickel catalysts, respectively, indicating that both reductive and oxidative quenching catalytic cycles can be operative, although the reductive cycle is favored.

Significant Impact of Exposed Facets on the BiVO Material Performance for Photocatalytic Water Splitting Reactions.

The impact of the four predominant (010), (110), (001), and (121) exposed facets obtained experimentally for monoclinic BiVO on its photocatalytic performance for water splitting reactions is investigated on the basis of the hybrid density functional theory including the spin-orbit coupling. Although their electronic structure is similar, their transport and redox properties reveal anisotropic characters based on the crystal orientation and termination. The particular role of each facet in proton reduction was correlated with the surface Bi coordination number and their geometrical distribution.

Designing an active TaN photocatalyst for H and O evolution reactions by specific exposed facet engineering: a first-principles study.

The effects of native defects and exposed facets on the thermodynamic stability and photocatalytic characteristics of Ta3N5 for water splitting are studied by applying accurate quantum computations on the basis of density functional theory (DFT) with the range-separated hybrid functional (HSE06). Among the three explored potential candidates for O-enriched bulk Ta3N5 structures with substituted O at N sites and accompanied by interstitial O or Ta-vacancies, the first and third structures are relevant. The four possible (001), (010), (100) and (110) low Miller index exposed facets of Ta(3-x)N(5-y)Oy (y = 7x) are also explored, which show lower formation energies than those of Ta3N5.

TiO-supported Pt single atoms by surface organometallic chemistry for photocatalytic hydrogen evolution.

A platinum complex, (CH)Pt(COD), is grafted via surface organometallic chemistry (SOMC) on morphology-controlled anatase TiO to generate single, isolated Pt atoms on TiO nano-platelets. The resulting material is characterized by FT-IR, high resolution scanning transmission electron microscopy (HRSTEM), NMR, and XAS, and then used to perform photocatalytic water splitting. The photocatalyst with SOMC-grafted Pt shows superior performance in photocatalytic hydrogen evolution and strongly suppresses the backwards reaction of H and O forming HO under dark conditions, compared to the photocatalyst prepared by impregnation at the same Pt loading.

The Comparison between Single Atom Catalysis and Surface Organometallic Catalysis.

Single atom catalysis (SAC) is a recent discipline of heterogeneous catalysis for which a single atom on a surface is able to carry out various catalytic reactions. A kind of revolution in heterogeneous catalysis by metals for which it was assumed that specific sites or defects of a nanoparticle were necessary to activate substrates in catalytic reactions. In another extreme of the spectrum, surface organometallic chemistry (SOMC), and, by extension, surface organometallic catalysis (SOMCat), have demonstrated that single atoms on a surface, but this time with specific ligands, could lead to a more predictive approach in heterogeneous catalysis.

Toward the Design of New Suitable Materials for Solar Water Splitting Using Density Functional Theory.

We report key results of a systematic computational investigation using density functional theory along with the two standard Perdew-Burke-Ernzerhof and hybrid Heyd-Scuseria-Ernzerhof (HSE06) exchange-correlation formalisms on essential fundamental parameters for solar energy conversion of a series of large, medium, and small selected (covalent, binary, and ternary) materials widely utilized in fuel cells, photocatalysis, optoelectronics, photovoltaics, and dye-sensitized solar devices such as BN, AlN, C, ZrO, NaTaO, BiTiO, ZnS, GaN, SrTiO, TiO, BiTiO, SiC, WO, TaON, ZnSe, BiVO, CuNbO, CdS, AlP, ZnTe, GaP, CuO, AlAs, TaN, BP, CdSe, SnWO, GaAs, CdTe, and Si. Our calculations highlight that the optoelectronic and redox parameters computed with HSE06 reproduce with very good accuracy the experimental results, thanks to precise electronic structure calculations. Applying this first-principle quantum methodology led us to provide a rational design of new suitable solid solution materials for visible light-driven photochemical water splitting.

Energy-Efficient Nitrogen Reduction to Ammonia at Low Overpotential in Aqueous Electrolyte under Ambient Conditions.

The electrochemical nitrogen reduction reaction (NRR) under ambient conditions is a promising alternative to the traditional energy-intensive Haber-Bosch process to produce NH . The challenge is to achieve a sufficient energy efficiency, yield rate, and selectivity to make the process practical. Here, we demonstrate that Ru nanoparticles (NPs) enable NRR in 0.

Insights into the Impact of Native Defects on the Conductivity of CuVO Material for Photovoltaic Application: A First-Principles Computational Study.

We report a theoretical study on the impact of native defects present in CuVO material on its conductivity using first-principles calculations based on density functional theory. We find a low and direct band gap of 1.4 eV for the pristine cell together with relatively high solar absorption efficiency, high macroscopic dielectric constant, and delocalized orbital characters of photogenerated charge carriers.

Morphology control of anatase TiO for well-defined surface chemistry.

A specific allotrope of titanium dioxide (anatase) was synthesized both with a standard thermodynamic morphology ({101}-anatase) and with a highly anisotropic morphology ({001}-anatase) dominated by the {001} facet (81%). The surface chemistry of both samples after dehydroxylation was studied by 1H NMR and FT-IR. The influence of surface fluorides on the surface chemistry was also studied by 1H NMR, FT-IR and DFT.

Ni-Sn-Supported ZrO Catalysts Modified by Indium for Selective CO Hydrogenation to Methanol.

Ni and NiSn supported on zirconia (ZrO) and on indium (In)-incorporated zirconia (InZrO) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO) catalysts showed a very high selectivity for methane (99%) during CO hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO (5% Ni-5% Sn/ZrO) showed the rate of methanol formation to be 0.

Ab initio assessment of BiRECuOS (RE = La, Gd, Y, Lu) solid solutions as a semiconductor for photochemical water splitting.

The investigation of the BiCuOCh (Ch = S, Se and Te) semiconductor family for thermoelectric or photovoltaic materials is a topic of increasing research interest. These materials can also be considered for photochemical water splitting if one representative having a bandgap, E, at around 2 eV can be developed. With this aim, we simulated the solid solutions BiRECuOS (RE = Y, La, Gd and Lu) from pure BiCuOS (E ∼ 1.

Impact of Interfacial Defects on the Properties of Monolayer Transition Metal Dichalcogenide Lateral Heterojunctions.

We explored the impact of interfacial defects on the stability and optoelectronic properties of monolayer transition metal dichalcogenide lateral heterojunctions using a density functional theory approach. As a prototype, we focused on the MoS-WSe system and found that even a random alloy-like interface with a width of less than 1 nm has only a minimal impact on the band gap and alignment compared to the defect-less interface. The largest impact is on the evolution of the electrostatic potential across the monolayer.

Suitable Fundamental Properties of TaVON Material for Visible-Light-Driven Photocatalysis: A DFT Study.

By applying calculations based on density functional theory, and on density functional perturbation theory, together with generalized gradient approximation-Perdew-Burke-Emzerho and screened Coulomb hybrid HSE06 functionals, we predict novel and suitable fundamental parameters of the stable monoclinic TaVON semiconductor for solar water splitting. In addition to its predicted bandgap of 2.0 eV in the required zone for solar-driven water splitting, this material reveals a high visible-light absorption coefficient, high static dielectric constant, high hole and electron mobilities along the [001] and [010] crystallographic directions, relatively low exciton binding energy, and suitable band edge energy levels for oxidizing water and reducing protons.

Determination of the electronic, dielectric, and optical properties of sillenite Bi12TiO20 and perovskite-like Bi4Ti3O12 materials from hybrid first-principle calculations.

Density functional theory calculation was conducted to determine the optoelectronic properties of bismuth titanate sillenite (Bi12TiO20) and perovskite-like (Bi4Ti3O12) structures. The lattice parameters were experimentally obtained from Rietveld analysis. The density functional perturbation theory approach was used with the standard Perdew-Burke-Ernzerhof functional and screened Coulomb hybrid Heyd-Scuseria-Ernzerhof functional to investigate the electronic structure and absorption coefficient.

Predicting suitable optoelectronic properties of monoclinic VON semiconductor crystals for photovoltaics using accurate first-principles computations.

Using accurate first-principles quantum calculations based on DFT (including the DFPT) with the range-separated hybrid HSE06 exchange-correlation functional, we can predict the essential fundamental properties (such as bandgap, optical absorption co-efficient, dielectric constant, charge carrier effective masses and exciton binding energy) of two stable monoclinic vanadium oxynitride (VON) semiconductor crystals for solar energy conversion applications. In addition to the predicted band gaps in the optimal range for making single-junction solar cells, both polymorphs exhibit a relatively high absorption efficiency in the visible range, high dielectric constant, high charge carrier mobility and much lower exciton binding energy than the thermal energy at room temperature. Moreover, their optical absorption, dielectric and exciton dissociation properties were found to be better than those obtained for semiconductors frequently utilized in photovoltaic devices such as Si, CdTe and GaAs.

Tuning the properties of visible-light-responsive tantalum (oxy)nitride photocatalysts by non-stoichiometric compositions: a first-principles viewpoint.

Finding an ideal photocatalyst for achieving efficient overall water splitting still remains a great challenge. By applying accurate first-principles quantum calculations based on DFT with the screened non-local hybrid HSE06 functional, we bring rational insights at the atomic level into the influence of non-stoichiometric compositions on essential properties of tantalum (oxy)nitride compounds as visible-light-responsive photocatalysts for water splitting. Indeed, recent experiments show that such non-stoichiometry is inherent to the nitridation methods of tantalum oxide with unavoidable oxygen impurities.