Green Energy Applications Research Articles

1D/2D Hybrid Te/Graphene and Te/MoS2: Multifaceted Broadband Photonics and Green-Energy Applications.

We highlight the enhanced electronic and optical functionalization in the hybrid heterojunction of one-dimensional (1D) tellurene with a two-dimensional (2D) monolayer of graphene and MoS2 in both lateral and vertical geometries. The structural configurations of these assemblies are optimized with a comparative analysis of the energetics for different positional placements of the 1D system with respect to the hexagonal 2D substrate. The 1D/2D coupling of the electronic structure in this unique assembly enables the realization of the three different types of heterojunctions, viz. type I, type II, and Z-scheme. The interaction with 1D tellurene enables the opening of a band gap of the order of hundreds of meV in 2D graphene for both lateral and vertical geometries. With both static and time-dependent first-principles analysis, we indicate their potential applications in broadband photodetection and absorption, covering a wide range of visible to infrared (near-IR to mid-IR) spectrum from 380 to 10 000 nm. We indicate that this 1D/2D assembly also has bright prospects in green-energy harvesting.

Novel Li rich perovskites Li4NBI3 (B = Ge, Sn, or Pb) with high mobility based on super alkali cation Li4N

It is an important research goal to find new environment-friendly and stable materials for sustainable and green energy applications. This paper reports a new type of super alkali perovskite Li4NBI3 (B = Ge, Sn, or Pb) with high mobility that was designed and studied by using the first-principle calculation method based on density functional theory. The geometrical structures, thermodynamic stability, electronic properties, transport properties, mechanical properties, and optical absorption properties of Li4NBI3 perovskites were calculated. The effects of the super alkali cluster Li4N on the structure and electronic properties of these perovskites were investigated. The results show that ionic bonds are formed between Li4N and I, and that the local energy state provided by Li4N increases the density of states at the edge of the energy band, which affects the energy band structure and pseudo-bandgap, and further affects the optical absorption coefficient and carrier mobility. Mechanical parameters showed that these three perovskites have high ductility, so they are suitable for making thin films. With high conductivity, strong light absorption, these perovskites are likely to become potential candidates for new energy materials.

(Invited) Carbon Dots – Unlocking Optical Properties for Applications in Imaging, Sensing and Energy

In recent years, nanomaterials (defined as materials < 100 nm in a single dimension) have garnered a significant interest for the development of novel applications in the physical and life sciences. One such class of nanomaterials are carbon dots, a relatively new member in the carbon allotrope family, which possesses versatile optical properties rendering it attractive for sensing, catalysis, bioimaging and drug delivery applications, to name a few. Their ultra-compact size, low cytotoxicity, resistance to photo-bleaching/blinking and tunable photoluminescence, combined with simple, environmentally-friendly and low-cost synthesis, makes them ideal candidates for study. We synthesize carbon dots via bottom-up synthesis methods, with simple organic precursors (e.g. citric acid) as the carbon source. We passivate the surface of our carbon dots to achieve high fluorescence quantum yields. Moreover, our work focuses on trying to elucidate the fluorescence mechanisms in carbon dots, which remain a subject of debate. Finally, we exploit their optical properties in order to design multifunctional materials as chiral, pH or temperature sensors, as well as heterogeneous catalysts for green energy applications.

A DFT study of optical, elastic, mechanical, and overall water-splitting photocatalytic properties of pristine and Cd substituted BaZrO3: A lead free environment friendly material

First principle calculations are taken into account to investigate different properties like overall water splitting, elastic, mechanical, optical, electronic, and structural, of pure along with cadmium-induced BaZrO3 which is an oxide-based perovskite. Ultra-soft pseudo-potential is integrated within Cambridge Serial Total Energy Package to explore these properties. Generalized gradient approximation suggested by Perdew-Burke Erzenhoff and hybrid functional is taken into account for exchange–correlation potential. Cadmium introduced at Ba site is more successful rather than Zirconiumas brand new gamma points appeared that also influenced the electronic formation of pure BZO minimized band gap from 3.114–0 eV and 4.203–0.470 eV by using GGA-PBE and HSE03 respectively. In Cd substitution case, Fermi level shifted to near valence band which reveals property of semiconductor material called p-type before showing conducting behavior at full replacement of Ba with Cd. Furthermore, mechanical properties derived from elastic constants i.e. Bulk modulus, Shear modulus, Young modulus, Poisson ratio, and finally these materials were established to justify born stability requirements. In addition, Cauchy's pressure along with Pugh's ratio also proved brittle nature of these material compositions. We explored and compared optical properties for example absorption spectra, refractive index (3.1), dielectric function, and reflectivity, as an energy loss function of pure BZO in comparison with Cd loaded BZO. Cd based BZO transforms optical performance considerably therefore this material is more effectivefor optoelectronic devices. Overall water splitting was studied for pure and Cd substituted BaZrO3. The pure and two and Six atoms doped material play a vital role for overall water splitting. It is proposed that the said materials are not only lead free for green energy applications in photocatalytic activity but also that the bandgap range is suitable for solar cell applications.

3D self-supporting nickel sponge substrate derived CoFeLDH/SN as an efficient bifunctional electrocatalyst for overall water splitting

The design and fabrication of high-efficiency and low-cost bifunctional catalysts in overall water splitting is crucial for the industrial application of green and clean hydrogen energy. Herein, a three-dimensional (3D) self-supporting nickel sponge (SN) with many nickel synapses prepared by hydrothermal method was employed as the substrate. 2D CoFeLDH nanosheets were grown on nano-Ni synapses of SN by electrodeposition method. For comparison, CoFeLDH also was deposited on a nickel foam (NF) substrate using the same deposition process. The as-prepared CoFeLDH/SN exhibited excellent electrocatalytic performances with 208 mV at 10 mA cm−2 for OER and 63 mV at 10 mA cm−2 for HER in 1 M KOH alkaline solution, which is better than that of CoFeLDH/NF (276 mV at 10 mA cm−2 for OER, and 173 mV at 10 mA cm−2 for HER). The electrolytic cell using CoFeLDH/SN as both cathode and anode achieves a voltage of 1.52 V at current density of 10 mA cm−2, which is better than that of most previously reported bifunctional catalysts. Our work provides a facile and inexpensive option for the design of bifunctional catalysts in overall water splitting.

A stable low-symmetry T-phase of MSi2Z4 (M = Mo, W; Z = P, As) nanosheets with promising electronic and photovoltaic properties: Insight from first-principles calculations

The synthesis of MoSi2N4 nanosheets boosts research on the layered MA2Z4 materials, which can be viewed as a MoS2-like MZ2 sheet sandwiched between two AZ surfaces. Most studies focus on the trigonal-prismatic (H-phase) MA2Z4 nanosheets, while the stable octahedral (T-phase) MA2Z4 ones are rarely explored. Here, based on first-principles calculations, we have identified a stable low-symmetry T-phase (Tl-phase) geometry for the MSi2Z4 (M = Mo, W; Z = P, As) materials. Such Tl-MSi2Z4 nanosheets are stabilized by the trimerization of metal atoms, which is distinct from the well-known T′-phase MoS2 system that favors the metal dimerization instead. The investigated Tl-MSi2Z4 nanosheets are all direct-gap semiconductors with moderate gap sizes around 1 eV and hence exhibit a strong absorption capacity to visible lights. High hole mobilities of 104–105 cm2/V s appear in the Tl-MSi2Z4 nanosheets that are dozens to hundreds of times larger than the electron mobilities. Moreover, superior photovoltaic performances are present in these Tl-MSi2Z4 materials, whose power-conversion efficiencies are estimated up to 26.1%–31.8% in a few micrometer thickness. In particular, the photovoltaic efficiency of the Tl-MoSi2P4 system can surpass the Shockley–Queisser limit and reaches 36.9%–39.5% under the concentration of 100–1000 suns illumination. Our study demonstrates that peculiar distorted T-phase geometries can exist in the layered MA2Z4 family, which exhibit promising electronic, transport, and photovoltaic behaviors for nanoelectronics, nano-devices, and green-energy applications.

Design of Aerosol Nanoparticles for Interfacial Catalysis.

Interest in multifunctional nanoparticles is currently rising due to the increasing demand in green energy and environmental applications. The aerosol-based synthetic route emerges as a promising method for enabling the fabrication of multifunctional nanoparticles in a continuous and scalable manner. Meanwhile, interfacial catalysis is receiving great attention to enhance the performance of chemical reactions. In this regard, the utilization of aerosol nanoparticles is highly beneficial to the catalysis field by the creation of strong metal-support-promoter interactions for promoting interfacial catalysis. In this Perspective, aerosol-based synthesis of hybrid nanoparticles is briefly discussed. In addition, the interfacial catalysis of CO oxidation, methane combustion, CO2 hydrogenation, and dry reforming of methane are discussed to provide fundamental insights and concepts for the rational design of nanocatalysts with efficient interfaces.

Electrodeposition of Lithium-Based Upconversion Nanoparticle Thin Films for Efficient Perovskite Solar Cells.

In this work, high-quality lithium-based, upconversion (UC) thin film was electrodeposited on fluorene-doped tin oxide (FTO) glass for solar cell applications. A complete perovskite solar cell (PSC) was fabricated on top of the FTO glass coated with UC thin film and named (UC-PSC device). The fabricated UC-PSC device demonstrated a higher power conversion efficiency (PCE) of 19.1%, an additional photocurrent, and a better fill factor (FF) of 76% in comparison to the pristine PSC device (PCE = ~16.57%; FF = 71%). Furthermore, the photovoltaic performance of the UC-PSC device was then tested under concentrated sunlight with a power conversion efficiency (PCE) of 24% without cooling system complexity. The reported results open the door toward efficient PSCs for renewable and green energy applications.

Photocatalytic and optical properties of (Mg:La) CaTiO3: Insights from first principles studies

Calcium titanate (CaTiO3) is widely employed in optoelectronic devices and the ceramic industry. The photocatalytic properties of calcium titanate are affected by substitution with transition metals. In this study, the simultaneous inclusion of Mg and La in CaTiO3 was investigated using density functional theory and the generalized gradient approximation functional of Perdew–Burke–Erzenhoff. Including elements had important effects on the structural, photocatalytic, optical, and electronic properties of semiconductor materials. Mg and La were introduced at the calcium sites at a ratio of 2:1. The effects of including Mg and La on the band structure, structural parameters, and optical properties, such as the absorption, static dielectric constant, and reflectivity, were elucidated in detail and clear correlations were also established between them. Co-doping had significant effects on the structural and electronic parameters. The band gap increased due to occupation of states in the conduction band. The static dielectric function decreased from 6 to 3.2, and the static refractive index with doping was 1.8. The reflectivity decreased from less than 20% in case of pure CaTiO3 to less than 10% with co-doping. Clear correlations were established between the electronic properties, such as the band gap and lattice parameter, and the optical properties in order to understand the results obtained. Water splitting was investigated for the pure and doped CaTiO3 in the ultraviolet and visible ranges. Pure and (Mg, La)–CaTiO3 exhibited oxygen evolution reaction activity. The materials are clearly lead-free and suitable for green energy applications because of their photocatalytic activities, and they also have an ideal band gap range for solar cell applications.

Theoretical study on electronic, optical, magnetic and photocatalytic properties of codoped SrTiO3 for green energy application

Motivated by the large scientific interest in development of double cation doping of SrTiO3 (STO) within the last years aiming to improve the water-splitting activity, electronic and ionic conductivity of STO, we study the effect of (La, X) and (Y, M) codoping (X = Al/Sc/Cr/Mn/Fe/Co/Ni/Mo, and M = Al/Cr/Mo) on the structure, electronic, magnetic, optical and photocatalytic properties (for water-splitting and CO2 reduction) of STO using spin-polarized hybrid density functional theory. In most considered cases, the X and M monodoping reduces the bandgap of STO more than the (La, X) and (Y, M) codoping, except for the case of (La, Ni) codoping. We found out La-/Y-doping, and (La/Y, Al)-/(La, Sc)-codoping cannot improve the conductivity of STO, while other monodopants and codopants can increase it. Our calculations have revealed that the best suited candidates for mono-/co-doped STO-based photocatalysts are Fe-/(La, Ni)-STO. Furthermore, we disclosed Fe-/Mn-/(La, Mn/Fe/Ni)-STO could be appropriate for spintronic applications.

Process-structure-properties relationship in low-cost thermoelectric iron silicide synthesis

A trade-off between thermoelectric performance and cost-effectiveness makes commercial thermoelectric power generation possible in green energy applications. In this direction, FeSi2 based thermoelectric material has excellent potential and possesses low-cost, earth abundance and non-toxic constituent elements; still, the thermoelectric performance of FeSi2 materials is inferior to other mid-temperature thermoelectric materials. Also, the fabrication methods and synthesis routes are complex and time-consuming processes, restricting their competitiveness in mid-temperature applications. This work reports a simple processing strategy for β-FeSi2 synthesis employing arc-melting and spark plasma sintering techniques. The improved thermoelectric performance and remarkable mechanical properties were realised using these techniques. A substantial improvement in the hardness value of ≃ 6.5 GPa and fracture toughness value of ≃ 3.18 MPa√m was achieved, mainly due to its microstructural features. The processing-structure-properties relationship was established to ensure FeSi2 based thermoelectric materials' commercial viability.

Recent progress of lead-free halide double perovskites for green energy and other applications

Recent progress of lead-free halide double perovskites for green energy and other applications

Carbon coated electric arc furnace dust prepared by one-pot pyrolysis: An efficient, low carbon footprint electrode material for lithium-ion batteries

This work offers useful insights into the evaluation of the electric arc furnace dust in green energy applications by surface engineering. To produce low-carbon-footprint electrodes, for the first time in the open literature, the practical pyrolysis (of sucrose) method is applied to create a nanometer-thick carbon layer over the dust. Advanced techniques are used to characterize the carbon-coated electric arc furnace flue dust morphologically, structurally, and chemically. Galvanostatic tests reveal that the carbon-coated dust exhibits 600 mAh g−1 discharge capacity after 250 cycles. The rate test proves that the carbon-coated dust can withstand a high current load (2A g−1) and delivers 540 mAh g−1 after 250 cycles when the current load is decreased to 0.1A g−1. This obtained capacity shows that with the correct material selection and process design, it is possible to produce low-carbon footprint electrodes at a low cost. Electrochemical characterizations indicate that the lithiation reaction of the carbon-coated dust takes place similarly to that of the anode materials which are made of synthetically fabricated carbon-coated transition metal oxides and/or ferrites. It is anticipated that this study sets an example for the valorization of the various industrial wastes in energy applications in the future.

Graphene-based metasurface solar absorber design with absorption prediction using machine learning

Solar absorber is required to absorb most of the energy of the solar spectral irradiance. We propose a graphene-based solar absorber design with two different metasurfaces to improve this absorption and increase the efficiency of the solar absorber. The metasurfaces are selected based on their symmetrical/asymmetrical nature (O-shape and L-shape). The O-shape metasurface design is showing better performance over the L-shape metasurface design. The absorption performance is also compared with AM 1.5 solar spectral irradiance to show the effectiveness of the solar absorber. The absorption values are also enhanced by varying the parameters like resonator thickness and substrate thickness. The proposed solar absorber design gives maximum absorption in the ultraviolet and visible range. Furthermore, the design is also showing a high and similar absorption rate over a wide angle of incidence. The absorption of O-shape metasurface design is also predicted using machine learning. 1D-Convolutional Neural Network Regression is used to develop a Machine Learning model to determine absorption values of intermediate wavelength for assorted values of angle of incidence, resonator thickness, and substrate thickness. The results of experiments reveal that absorption values may be predicted with a high degree of accuracy. The proposed absorber with its high absorbing capacity can be applied for green energy applications.

N and S Dual-Doped Mesoporous Carbon Nanostructure as a High Performance and Durable Metal Free Oxygen Reduction Reaction Electrocatalyst

Discovering a high performance, durable, and cost-effective oxygen reduction reaction (ORR) electrocatalyst is a key strategy for widespread use of the high efficiency and environmentally friendly fuel cell and metal-air battery technologies. Herein, we fabricate a high performance and durable metal free N and S dual-doped mesoporous carbon nanostructure (NS-VXC) ORR catalyst using solid state thermolysis at 700 °C for 1 h. The fabricated catalyst exhibits nanocarbon aggregated chain-like morphology with a high surface area and mesoporous structure. The amount of N and S dopants embedded in mesoporous carbon nanostructure is found to be 3.2 and 1.1%, respectively which significantly attribute to the synergistic effect of spin and charge density leading to not only superior ORR performance but excellent durability in the alkaline environment as well. Rotating ring disk electrode analysis reveals the codoped NS-VXC catalyst possesses a direct 4-electron transfer number pathway with extremely low peroxide intermediate content. Compared to the benchmark Pt/C catalyst, the fabricated NS-VXC catalyst generated 10 mV ORR performance outperform and negligible performance degradation after the 10,000 ORR cycling test. These results suggest that an innovative solid state thermolysis methodology can be a powerful nanomaterial fabrication technique to generate high performance and excellent durability electrocatalyst for green energy applications.

Theoretical Study on Electronic, Optical,Magnetic and Photocatalytic Properties Ofco-Doped Srtio3 for Green Energy Application

Theoretical Study on Electronic, Optical,Magnetic and Photocatalytic Properties Ofco-Doped Srtio3 for Green Energy Application

Erratum: Alhasnawi et al. A New Robust Control Strategy for Parallel Operated Inverters in Green Energy Applications. Energies 2020, 13, 3480

The authors wish to make the following corrections to this paper [...]

Research and Development of a Wireless Self-Powered Sensing Device Based on Bridge Vibration Energy Collection.

Traditional bridge monitoring has found it difficult to meet the current diversified needs, and frequent replacement of sensor batteries is neither economical nor environmentally friendly. This paper presents a wireless acceleration sensor with low power consumption and high sensitivity through integrated circuit design, data acquisition and wireless communication design, package design, etc. The accuracy of the sensor in data collection was verified through calibration and performance comparison tests. The ability of triangular piezoelectric cantilever beam (PCB) was tested through design and physical manufacture. Finally, the self-powered performance of the sensor was tested by connecting the sensor and the triangular PCB through a circuit, which verifies the feasibility of using the PCB to collect bridge vibration energy and convert it into electrical energy to supply power for sensor, and also explore the green energy collection and application.

Synthesis of Value Added Nanoparticles from Biomass Resources

The utilization of sustainable biomass materials provides a versatile route for the development of new alternatives to replace traditional petro-materials for a variety of purposes such as green energy, paint, food packaging and biomedical applications. This study reviews the potential use of various sustainable biomass materials for the production of low-cost, highvalue- added materials for practical applications including bio-printing, drug delivery/controlled release, tissue engineering, energy storage and biosensing. This study highlights the fabrication of novel nanomaterials from various biowastes including crop residue, food waste and industrial waste (e.g. spent battery waste and polythene waste) through physical, chemical, or biological methods.

The Fabrication of Lead‐Free Cs2SnI6 Perovskite Films Using Iodine‐Rich Strategy for Optoelectronic Applications

Parallel to the booming of all‐inorganic CsPbX3 halide perovskites, the growth of lead‐free perovskites is accelerating, with the efficiency values of over 10% being realized. Eco‐friendly and stable halide double perovskites with superior stability are considered as an encouraging alternative to address the stability concerns related to the lead halide perovskites. Recently, Cs2SnI6 with defect perovskite structure has appeared as a “superstar” material owing to its environmental friendliness and exceptional stability. Herein, an iodine‐rich strategy (IRS) is developed based on the modified two‐step method for the fabrication of lead‐free Cs2SnI6 films. In addition, the impact of the reaction temperature on the properties of the resultant films is systematically investigated. The results reveal the improvement in the crystallinity and phase stability of the films, suggesting that the proposed IRS successfully inhibits the decomposition of Cs2SnI6 films. The optical measurements confirm the n‐type nature of Cs2SnI6 with bandgap varying from 1.23 to 1.38 eV. The photoluminescence of the films increases gradually with the addition of I2, presumably owing to the reduction of nonrecombination sites. The current work provides valuable direction for the fabrication of Cs2SnI6 devices for green energy applications.