Water Splitting Reaction at Polar Lithium Niobate Surfaces

High-entropy-based nano-materials for sustainable environmental applications

High entropy materials (HEMs), epitomized by high entropy alloys (HEAs), have sparked immense interest for a range of clean energy and environmental applications due to their remarkable structural versatility and adjustable characteristics. In the face of environmental challenges, HEMs have emerged as valuable tools for addressing issues ranging from wastewater remediation to energy conversion and storage. This review provides a comprehensive exploration of HEMs, spotlighting their catalytic capabilities in diverse redox reactions, such as carbon dioxide reduction to value-added products, degradation of organic pollutants, oxygen reduction, hydrogen evolution, and ammonia decomposition using electrocatalytic and photocatalytic pathways. Additionally, the review highlights HEMs as novel electrode nanomaterials, with the potential to enhance the performance of batteries and supercapacitors. Their unique features, including high capacitance, electrical conductivity, and thermal stability, make them valuable components for meeting crucial energy demands. Furthermore, the review examines challenges and opportunities in advancing HEMs, emphasizing the importance of understanding the underlying mechanisms governing their catalytic and electrochemical behaviors. Essential considerations for optimizing the HEM performance in catalysis and energy storage are outlined to guide future research. Moreover, to provide a comprehensive understanding of the current research landscape, a meticulous bibliometric analysis is presented, offering insights into the trends, focal points, and emerging directions within the realm of HEMs, particularly in addressing environmental concerns.

From Waste to Resource: Valorization of Lignocellulosic Agri-Food Residues through Engineered Hydrochar and Biochar for Environmental and Clean Energy Applications-A Comprehensive Review

Agri-food residues or by-products have increased their contribution to the global tally of unsustainably generated waste. These residues, characterized by their inherent physicochemical properties and rich in lignocellulosic composition, are progressively being recognized as valuable products that align with the principles of zero waste and circular economy advocated for by different government entities. Consequently, they are utilized as raw materials in other industrial sectors, such as the notable case of environmental remediation. This review highlights the substantial potential of thermochemical valorized agri-food residues, transformed into biochar and hydrochar, as versatile adsorbents in wastewater treatment and as promising alternatives in various environmental and energy-related applications. These materials, with their enhanced properties achieved through tailored engineering techniques, offer competent solutions with cost-effective and satisfactory results in applications in various environmental contexts such as removing pollutants from wastewater or green energy generation. This sustainable approach not only addresses environmental concerns but also paves the way for a more eco-friendly and resource-efficient future, making it an exciting prospect for diverse applications.

Ternary pentagonal BXN (X = C, Si, Ge, and Sn) sheets with high piezoelectricity

The discovery of new and stable two-dimensional pentagonal materials with piezoelectric properties is essential for technological advancement. Inspired by recently reported piezoelectric materials penta-BCN and penta-BSiN, we proposed penta-BGeN and penta-BSnN as new members of the penta-family based on first-principles calculations. Comprehensive analyses indicated that both penta-BGeN and penta-BSnN are thermodynamically, dynamically, mechanically, and thermally stable. In terms of mechanical stability, the elastic constant decreased as lower elements in group 4A of the periodic table were used. Therefore, penta-BGeN and penta-BSnN are softer than penta-BCN and penta-BSiN. In terms of piezoelectric properties, piezoelectric stress and strain tensors increase following the same pattern. In group 4A, penta-BSnN had the highest intrinsic piezoelectricity, especially the e 22 piezoelectric stress. Typically, the piezoelectric strain d ij coefficient increases with material softness; penta-BSnN possessed the highest d ij . Thus, due to its inherent piezoelectricity, penta-BSnN has tremendous potential as a nanoscale piezoelectric material.

High-density electron transfer in Ni-metal-organic framework@FeNi-layered double hydroxide for efficient electrocatalytic oxygen evolution

The electrochemical oxygen evolution reaction is a bottleneck reaction in hydrolysis and electrolysis because the four-step electron transfer leads to slow reaction kinetics and large overpotentials. This situation can be improved by fast charge transfer by optimizing the interfacial electronic structure and enhancing polarization. Herein, a unique metal (Ni) organic (diphenylalanine, DPA) framework Ni(DPA)₂ (Ni-MOF) with tunable polarization is designed to bond with FeNi-LDH (layered double hydroxides) nanoflakes. The Ni-MOF@FeNi-LDH heterostructure delivers excellent oxygen evolution performance exemplified by an ultralow overpotential of 198 mV at 100 mA cm^-2 compared to other (FeNi-LDH)-based catalysts. Experiments and theoretical calculations show that FeNi-LDH exists in an electron-rich state in Ni-MOF@FeNi-LDH due to polarization enhancement caused by interfacial bonding with Ni-MOF. This effectively changes the local electronic structure of the metal Fe/Ni active sites and optimizes adsorption of the oxygen-containing intermediates. Polarization and electron transfer of Ni-MOF are further enhanced by magnetoelectric coupling consequently giving rise to better electrocatalytic properties as a result of high-density electron transfer to active sites. These findings reveal a promising interface and polarization modulation strategy to improve electrocatalysis.

Study of Phenol Red Photocatalytic Decomposition on KBrO3-Supported TiO2 Nanoparticles for Wastewater Treatment

In this study, the enhanced photodegradation of a high-concentration phenol red (PR) using very fine TiO2 nanocrystals by adding a KBrO3 electron acceptor was reported for the first time. The structural study on TiO2 nanocrystals using HRTEM, XRD, Raman, and EDX was performed and it confirmed the anatase phase of TiO2 nanocrystals. UV–Vis absorbance of 20 mg.L−1 PR was measured and the photodegradation was extracted. The KBrO3 concentration effects exhibited an important enhancement in the degradation of PR dye. The efficiency of PR was increased during 110 min from 75% of pure TiO2 to 92% and 98% of TiO2 with 1 mg and 5 mg KBrO3, respectively. For different samples, a first-order kinetic of dye degradation is confirmed. The instantaneous amount of degraded dye increased from 150 to 180 and 197 mg/g TiO2 with 1 mg and 5 mg KBrO3, respectively. The mechanism of the photodegradation reaction confirms the effect of OH- radicals on increasing the photocatalytic activities. The addition of electron acceptors KBrO3 improved the photocatalysis rate, where it prevented e-h recombination through conduction band electron capture, which increases the concentration of hydroxyl radicals. The proposed mechanism and results were supported by photocurrent measurements and a Raman spectra analysis of the final photodegraded products. The photocurrent of TiO2 was observed at 1.2 µA, which was significantly improved up to 13.2, and 21.3 µA with the addition of 1 mg and 5 mg of KBrO3. The Raman spectra of the final products confirmed that SO42− and carbons are byproducts of PR degradation.

Water/InP(001) from Density Functional Theory

The interface between water and the In-rich InP(001) surface is studied by density functional theory with water coverage ranging from single molecules to multiple overlayers. Single molecules attach preferably to three-fold coordinated surface In atoms. Water dissociation is energetically favorable but hindered by an energy barrier that decreases with increasing water coverage. There is an attractive interaction between InP adsorbed water molecules that leads to the formation of molecular clusters and complete water films for water-rich preparation conditions. Water films on InP are stabilized by anchoring to surface-bonded hydroxyl groups. With increasing thickness, the water films resemble the structural properties of ice Ih. The oxygen and hydrogen evolution reactions on InP are characterized by overpotentials of the order of 1.7-1.8 and 0.2-0.3 eV, respectively. While the calculated bulk positions of the InP band edges are outside the range of the redox potentials for oxygen and hydrogen evolution within local DFT, the situation is different at the actual interface: Here, the interface dipole lifts the InP valence band maximum above the redox potential for oxygen evolution and favors hydrogen evolution.

Pulsed Laser in Liquids Made Nanomaterials for Catalysis

Catalysis is essential to modern life and has a huge economic impact. The development of new catalysts critically depends on synthetic methods that enable the preparation of tailored nanomaterials. Pulsed laser in liquids synthesis can produce uniform, multicomponent, nonequilibrium nanomaterials with independently and precisely controlled properties, such as size, composition, morphology, defect density, and atomistic structure within the nanoparticle and at its surface. We cover the fundamentals, unique advantages, challenges, and experimental solutions of this powerful technique and review the state-of-the-art of laser-made electrocatalysts for water oxidation, oxygen reduction, hydrogen evolution, nitrogen reduction, carbon dioxide reduction, and organic oxidations, followed by laser-made nanomaterials for light-driven catalytic processes and heterogeneous catalysis of thermochemical processes. We also highlight laser-synthesized nanomaterials for which proposed catalytic applications exist. This review provides a practical guide to how the catalysis community can capitalize on pulsed laser in liquids synthesis to advance catalyst development, by leveraging the synergies of two fields of intensive research.

Asymmetrical 1st reflection trend owing to metallization difference at ± Z-faces in indium tin oxide coated Fe-doped lithium niobate

The charges accumulated at the interface of indium tin oxide (ITO) and iron doped lithium niobate (LN) in an extremely thin layer because of semiconductor band alignment were analyzed with ab initio theory. The formation of 2D electron gas makes the interface metallic and the excitation of surface plasmon polaritons (SPPs) possible. In experiments, diametrically opposite trends of the very first reflection (VFR) on the ± Z-faces of ITO coated Fe-LN slabs were observed and associated with the differences in metallization and the photovoltaic charge accumulation there. Microscopically, the electric environments of the two ITO/LN interfaces differ greatly owing to spontaneous polarization and photovoltaic fields, which alter the band structures and band alignment, resulting in phase gratings with a π-shift difference recorded at the two interfaces. This affects the opposite energy coupling between the SPPs and laser beams and results in the dramatically opposite trends of VFR.