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When combined with ceramics, ternary carbides, nitrides, and borides form a class of materials known as MAX phases. These materials exhibit a multilayer hexagonal structure and are very strong, damage tolerant, and thermally stable. Further, they have a low thermal expansion and exhibit outstanding resistance to corrosion and oxidation. However, despite the numerous MAX phases that have been identified, the search for better MAX phases is ongoing, including the recently discovered Zr3InC2 and Hf3InC2. The properties of MAX phases are still being tailored in order to lower their ductility. This study investigated Ti3AlC2 alloyed with nitrogen, gallium, hafnium, and zirconium with the aim of achieving better mechanical and thermal performances. Density functional theory within Quantum Espresso module was used in the computations. The Perdew–Burke–Ernzerhof generalised gradient approximation functionals were utilised. (ZrHf)4AlN3 exhibited an enhanced bulk and Young’s moduli, entropy, specific heat, and melting temperature. The best thermal conductivity was observed in the case of (ZrHf)3AlC2. Further, Ti3AlC2 exhibited the highest shear modulus, Debye temperature, and electrical conductivity. These samples can thus form part of the group of MAX phases that are used in areas wherein the above properties are crucial. These include structural components in aerospace and automotive engineering applications, turbine blades, and heat exchanges. However, the samples need to be synthesised and their properties require verification.

Cadmium-tin-oxide (CTO), also referred to as cadmium stannate (Cd2SnO4), is known for its interesting electrical, electronic, and optical properties, making it useful in various applications such as in transparent conducting oxides for optoelectronic devices and also in photovoltaic applications. While its properties have been investigated experimentally, there is not much record in the literature on the computational study of the electronic and optical properties of CTO. This study employed density functional theory to explore the two properties of CTO. The hybrid functionals were used to widen the band gap from 0.381 eV (for PBE) to 3.13 eV, which replicates the experimental values very well. The other properties obtained were a refractive index of 2.53, absorption coefficient of 1.43 × 104 cm−1, and dielectric constant of 6.401 eV. The optical energy loss of 0.00691 that was investigated for the first time in this work adds to the literature on the properties of CTO. However, the electrical properties of CTO, which also play a key role in the working of optoelectronic devices, need to be investigated.

Yttrium nitride (YN) is a hard and refractory material with a high melting point. It is a semiconductor that has been investigated for its potential applications in the field of semiconductor technology, including as a material for electronic devices. It is also of interest for its optical properties and its potential for use in optoelectronics. However, investigating its mechanical properties for a possible application in optical coatings has not been completed. This study involved the exploration of the mechanical properties of YN alloyed with niobium (Nb) and zirconium (Zr) for possible application in optical coatings using a first-principles approach. The result showed that the addition of Nb and Zr into the YN matrix had a profound effect on the mechanical properties of the modeled structures, with the Y-N-Nb (CYN_5) sample having the best mechanical properties. The bulk modulus was the most affected, with an increase of 26.48%, while the Vickers hardness had the smallest increase of 6.128% compared with those of pure YN. The modeled structures were thus found to be ideal alternative materials for optical coatings due to their improved mechanical properties.

Cadmium stannate (Cd2SnO4) exhibits both transparency and electrical conductivity, making it useful for applications where visible light needs to pass through the material while maintaining an electrical connection, such as in the manufacture of thin–film transistors for application in liquid crystal displays and other electronic devices. Most of the properties of Cd2SnO4 have been investigated and are well documented. However, its thermoelectric properties have not been explored. The present study investigates its thermometric properties for the first time using density functional theory within the generalized gradient approximation, both without (GGA) and with the Hubbard correction (GGA+U). Quantum Espresso and BoltzTrap2 codes are utilized. The Perdew–Burke–Ernzerhof functional for solids exchange‐correlation functionals with ultrasoft pseudopotentials are involved in the calculations. The outcome showed that Cd2SnO4 possesses desirable thermoelectric properties, of which some are better than those of the common thermoelectric materials. The Seebeck coefficient exhibited both positive and negative values, whereas the Hall coefficient verified its n‐type conductivity. The use of GGA+U resulted in higher values of the thermoelectric properties. Cd2SnO4 can therefore be tried in the thermoelectric applications such as in magnetic sensors and magnetic memory storage due to its good thermoelectric properties. However, an experimental validation of the calculated thermoelectric properties is still required. Cd2SnO4 exhibits excellent thermoelectric properties with a high Seebeck coefficient, power factor, and figure of merit, surpassing Bi2Te3. It shows both positive and negative Seebeck coefficient values, making it suitable for diverse applications. Its high electrical conductivity and low thermal conductivity enhance efficiency, while its negative Hall coefficient confirms its n‐type behavior and strong potential for energy conversion and cooling devices.

Perovskites are currently becoming common in the field of optoelectronics, owing to their promising properties such as electrical, optical, thermoelectric, and electronic. Although mechanical and thermal properties also play a crucial part in the functioning of the optoelectronic devices, they have scarcely been explored. The present work performed an ab initio study of the mechanical and thermal properties of the cubic EuAlO3 and GdAlO3 perovskites for the first time using density functional theory. Quantum Espresso and Themo_pw codes were utilized by employing the generalized gradient approximation. Although the results showed that both materials have good mechanical and thermal properties that are ideal for the above–mentioned applications, EuAlO3 possessed better structural and thermal stability, bulk modulus, Poisson ratio, thermal expansion coefficient, and thermal stress; while GdAlO3 possessed better Young’s modulus and shear modulus. Moreover, the mechanical properties of the two materials turned out to be much better than those of the common materials for optoelectronic applications, while their thermal properties were comparable to that of sapphire glass. Since this study was computational, an experimental verification of the computed properties of the two materials needs to be carried out before they can be commercialized.

The exploration of chalcogenides is on the rise owing to their desirable optical, electronic, thermoelectric, and thermal properties. Chalcogenide materials have been investigated for possible applications in areas such as non-linear optics and solar cells. Among these materials are BaTiS3 and BaTiSe3. BaTiS3 has shown promise in the above-mentioned applications due to its low thermal conductivity. However, neither the thermal properties of BaTiSe3 nor the mechanical properties of both BaTiS3 and BaTiSe3 have been reported. In this work, we performed a computational study of the mechanical and thermal properties of both materials within the density functional theory using Quantum Espresso and BoltzTrap2 codes, employing generalized gradient approximation. The results showed that the computed thermal conductivity of BaTiS3 at 0.43 W/m/K is comparable to the literature values. The computed elastic constants of BaTiS3 (bulk modulus of 44.7 GPa, shear modulus of 11.2 GPa, Young’s modulus of 29.6 GPa, and Vickers hardness of 1.053 GPa) were higher than those of BaTiSe3. The calculated properties obtained in this work add to the literature on the properties of BaTiS3 and BaTiSe3. However, since the work was computational, the results can be verified by an experimental investigation.

Microbial Electrolysis Cells (MECs) are one of the bioreactors that have been used to produce bio-hydrogen by biological methods. The objective of this comprehensive review is to study the effects of MEC configuration (single-chamber and double-chamber), electrode materials (anode and cathode), substrates (sodium acetate, glucose, glycerol, domestic wastewater and industrial wastewater), pH, temperature, applied voltage and nanomaterials at maximum bio-hydrogen production rates (Bio-HPR). The obtained results were summarized based on the use of nanomaterials as electrodes, substrates, pH, temperature, applied voltage, Bio-HPR, columbic efficiency (CE) and cathode bio-hydrogen recovery (C Bio-HR). At the end of this review, future challenges for improving bio-hydrogen production in the MEC are also discussed.

Ranging from the most demanding technical applications to soft, extremely ductile wrapping foil, aluminum is one of the most versatile and reasonably priced metallic materials. These are attributable to the unique blend of features that it provides, together with its alloys, owing to its lightweight, and some of its alloys have higher strengths than that of structural steel. However, it is expected that the demand for aluminum will quadruple within the next 10 years, and as a result, the aerospace industry is increasingly turning to recycled alloys to fulfill its high demand. This study uses the ab initio method, implemented in the quantum espresso code, to examine the influence of pressure on the structural and mechanical properties of cubic silicon carbide alloyed with aluminum (Al) and magnesium (Mg). The study is motivated by the aerospace industry’s growing need for sustainable materials. Some of the carbon atoms were swapped out for Al or Mg or both (co-doping) atoms in order to create the alloys. The results demonstrated that the application of pressure significantly influences both the structural and mechanical properties of the alloys, making them a promising option for the construction of environmentally friendly aircraft components.

Perovskites have become the center of recent research for their possible application in perovskite solar cells, owing to their desirable optical and electronic properties, flexibility, tunability, and low–cost fabrication. Most of the perovskites are however made of lead, which is a highly poisonous element. It is therefore necessary to seek alternative perovskites for this application that are less toxic. This study investigated the elastic, electronic, and thermoelectric properties of Cs–X–I (X = Pb, Gd, Nd, and Y) as possible replacements to the leaded CsPbI 3 due to their less toxic nature. The density functional theory was utilized in the computations, with quantum espresso and BoltzTrap packages. The results showed that all the materials were structurally stable. The computed mechanical properties also showed that all the other materials had better elastic constants compared to those of CsPbI 3 . CsPbI 3 was observed to exhibit the lowest band gap, unlike the others. Moreover, the other materials possessed higher elastic constants, electrical conductivities, and lowest thermal conductivities, which are highly needed in the perovskite solar cells. However, an experimental treatment needs to be done on the studied structures in order to confirm the properties obtained in this work.

The search for biocompatible, non-toxic, and wear-resistant materials for orthopedic implant applications is on the rise. Different materials have been investigated for this purpose, some of which have proved successful. However, one challenge that has proven difficult to overcome is the balance between ductility and hardness of these materials. This study employed ab initio calculations to investigate the structural and mechanical properties of niobium nitride (NbN) alloyed with hafnium, indium, and zirconium, with the aim of improving its hardness. The calculations made use of density function theory within the quantum espresso package’s generalized gradient approximation, with Perdew–Burke–Ernzerhof ultrasoft pseudopotentials in all the calculations. It was found that addition of the three metals led to an improvement in both the shear and Young’s moduli of the alloys compared to those of the NbN. However, both the bulk moduli and the Poisson’s ratios reduced with the introduction of the metals. The Young’s moduli of all the samples were found to be higher than that of bone. The Vickers hardness of the alloys were found to be significantly higher than that of NbN, with that of indium being the highest. The alloys are therefore good for wear-resistant artificial bone implants in ceramic acetabulum, and also in prosthetic heads.