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Indium hydroxide (In(OH)

In this work, we tailor facile hydrogels nanocomposite (HNC) based on sustainable karaya gum for water treatment. Karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ silver nanoparticle (KG-cl-P(AAm-co-AN)@AgNPs) HNC were made by an aqueous free radical in situ crosslink copolymerization of acrylamide (AAm) and acrylic acid (AA) in aqueous solution of KG-stabilized AgNPs. FTIR, XRD, DTA-TGA, SEM, and TEM were used to characterize HNC. The hydrogels' swelling, diffusion, and network characteristics were investigated. The removal efficiency of HNC was found to be 99% at pH 8 for a crystal violet (CV), dose of 0.02 g after 1 h. Dye adsorption by these hydrogels was also investigated in terms of isotherms, and kinetics. The dye's exceptionally high adsorption capacity on HNC for CV removal is explained by H-bonding interactions, as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules (Qmax, 1000 mg/g). The HNC can be regenerated with 0.1 M HCl and reused at least 10 times maintaining over 68% dye removal. The loading of AgNPs into the polymeric matrix of KG-cl-P(AAm-co-AN) significantly increases the removal percentage of CV dye from its aqueous solution, according to this study.

This study aimed to improve the long-term durability of CdS catalysts by reducing the deterioration of catalytic activity caused by photocorrosion. An ultrathin 1T-WS2 2D nanosheet was introduced to enclose the CdS nanorods. The crystal defects in the wrapped CdS particles were reduced, and the WS2 sheet became thinner in the junction particle. The 2CdS@1WS2 junction particle exhibited the slowest decay time of the photoluminescence curve, and the photocurrent density increased by more than 3.5-fold in the junction particle than the single CdS particle. Eventually, the optimized 2CdS@1WS2 catalyst exhibited a high rate of H2 production of ≈3935 μmol g−1h−1 under simulated solar light irradiation with a quantum efficiency of 50%. Although the recycling experiment was repeated over 10 times using the 2CdS@1WS2 junction particle, the produced hydrogen amount did not decrease. This result is because CdS nanorods wrapped stably by the ultrathin WS2 nanosheets, which suppressed the photocorrosion of CdS, and furthermore, the 1T phase WS2 rapidly attracted photogenerated electrons from CdS, facilitating charge separation and inhibiting their recombination, thereby improving the catalyst activity. Finally, it was revealed that an effective Z-scheme charge transfer mechanism in the CdS@1T-WS2 junction particle follows during water splitting.

Photocatalysis is a promising approach for generating hydrogen, an eco-friendly and cost-effective fuel. It is hypothesized that the ternary catalyst ZnIn2S4-rGO-CuInS2, prepared by ultrasonication method, should be effective for optimized photocatalytic hydrogen generation in a Na2S/Na2SO3−water mixture. The as-synthesized catalyst was characterized using various surface analytical and optical techniques. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy analyses revealed that marigold-like structured ZnIn2S4 and layer-structured CuInS2 were dispersed on the reduced graphene oxide sheets. The ternary ZnIn2S4-rGO-CuInS2 system showed enhanced photocatalytic H2 production compared to pure ZnIn2S4, CuInS2, ZnIn2S4-rGO, CuInS2-rGO, and ZnIn2S4-CuInS2 catalysts under visible light illumination. The fabricated ZnIn2S4-rGO-CuInS2 catalyst afforded hydrogen generation of 2531 μmol/g after 5 h. The enhanced performance of the ZnIn2S4-rGO-CuInS2 catalyst originates from the synergetic effect with rGO as the electron transfer medium, and is confirmed by photocurrent density and photoluminescence measurements that indicate reduced recombination between the excited electron and hole pairs, and fast electron transfer in the ternary composite. The excellent performance of the ZnIn2S4-rGO-CuInS2 catalyst for up to three consecutive cycles was demonstrated in cyclic stability tests under visible-light illumination.

Zinc and copper are considered as excellent metals for oxidation and reducibility, respectively. This study aims to obtain a redox-coupled composite semiconductor, wherein oxides of Zn and Cu were obtained and junctioned, for application as a photocatalyst in hydrogen production. To create a large number of activated sites on the catalyst's surface, the morphologies of the catalysts were controlled and several angular parts were formed. During the junction process, Cu2O and ZnO particles were controlled in cubic and starfish shapes, respectively, and the structure of the junctioned Cu2O/ZnO composite was similar to that of a chrysanthemum flower. Kubelka–Munk and Mott–Schottky plots demonstrated that ZnO and Cu2O have band gaps of 3.2 and 1.9 eV, respectively, and they are n- and p-type semiconductors, respectively. The TRPL and IMVS, as well as the photocurrent density and IMPS, confirmed that the recombination between electrons and holes in the junctioned Cu2O/ZnO particles was very slow, and effective charge separation was achieved. As a result, the amount of hydrogen generated from the junction catalyst was significantly higher than that generated from the single catalysts. In particular, the accumulated amount of evolved hydrogen after 10 h in the 2Cu2O/1ZnO junction catalyst was 2089.5 μmol. Results obtained from spin-trapping ESR experiments suggest that the charge-transfer mechanism in the redox-coupled 2Cu2O/1ZnO junction catalyst follows the S-scheme with a stronger reducing power.

The objective of this study was to replace some of the metal ions in the n-type zinc ferrite spinel lattice with Ni2+ ions to evaluate its catalytic behavior during water splitting. XPS and Raman spectroscopy revealed that the substituted Ni2+ ions were preferentially located at the octahedral (Oh) sites in the zinc ferrite spinel lattice, rather than the tetrahedral (Td) sites. When the amount of substituted Ni2+ was >0.6 mol, the crystal structure was converted to an inverse spinel structure. Ni2+ substitution resulted in the formation of oxygen vacancies in the spinel lattice. With Ni2+ substitution, the bandgap state changes from direct to indirect. The TRPL, IMVS, and IMPS analyses revealed the carrier diffusion length, e−/h+ recombination time, and charge transport rate for the Zn1-xNixFe2O4 inverse spinel. The electrons excited from the valence bands (VBs) to the CBs (O 2p → Fe3+ 3d) moved to Ni2+ 3d (Fe3+ 3d → Ni2+ 3d) and, subsequently, the longer carrier diffusion length suppressed e−/h+ recombination. Eventually, an optimum hydrogen production of 19.2 μmol g−1 was achieved using the Zn0.4Ni0.6Fe2.0O4 catalyst for a 10 h-hydrogen evolution reaction in neutral water splitting, without any sacrificial agent under visible light; Zn0.4Ni0.6Fe2.0O4 exhibited a four-fold improvement compared to ZnFe2O4. The material did not significantly deteriorate the catalytic performance, even after six regeneration experiments, and the catalyst material was separated using a magnet after the reaction. Thus, the goal of this study was to develop a simple, eco-friendly, and efficient catalyst via partial cation substitution in the spinel structure.

Bimetallic alloy nanospheres hybridized with semiconductor square-shaped discs are promising catalysts for photocatalytic water splitting, because they exhibit multicomponent interactions, high catalytic activity, and stability. Herein, Cu-Pd/N-Bi2WO6 heterostructures consisting of bimetallic Cu-Pd alloy nanospheres uniformly dispersed on N-Bi2WO6 square-shaped discs are reported. The as-prepared 1 wt% Cu-Pd/N-Bi2WO6 catalyst exhibits a higher H2 production rate (4213 µmol/g) under simulated solar light illumination than N-Bi2WO6 (291 µmol/g). The considerably high H2 production rate is ascribed to the exposed catalytically active sites of the Cu-Pd alloy nanospheres, which facilitate the formation of rapid charge transfer channels between Cu-Pd and N-Bi2WO6. Moreover, the photocatalyst stability is improved by aggregation of the highly dispersed Cu-Pd alloy nanospheres on the N-Bi2WO6 surface. Accordingly, a reaction mechanism based on the work functions of the bimetallic Cu-Pd alloy nanospheres and N-Bi2WO6 square-shaped discs is proposed to elucidate the photocatalytic reaction pathway. The holes (which accumulate in the N-Bi2WO6 square-shaped discs) and Pd (which acts as an electron channel) can effectively inhibit the recombination of charge carriers, and Cu (which acts as the cocatalyst) can synergistically increase the H+ reduction rate. This study provides a new effective route for the design of high-performance heterostructures for efficient photocatalytic H2 production.

n-tetracosane (C24H50), a phase change material (PCM) that undergoes a phase transition at 50.6 °C, was successfully encapsulated by silica (SiO2) as shell material in order to prevent it from leakage in this study (n-tetracosane@SiO2). Additionally, silver nanoparticles (Ag NPs) with various sizes (20, 40, and 80 nm) having excellent thermal conductivity were loaded on the capsules to improve its thermal conductivity (n-tetracosane@SiO2@Ag NPs). It has been found that the encapsulation capacity, the thermal conductivity of the capsule, and the degree of n-tetracosane leakage affect the thermal energy storage capacity of the encapsulated n-tetracosane@SiO2@Ag NPs. As the size of Ag NPs loaded on the encapsulated n-tetracosane@SiO2 increased the thermal conductivity of capsules increased, especially when the Ag NPs of 80 nm was loaded the thermal conductivity was enhanced more than three and two times compared to pure n-tetracosane and n-tetracosane@SiO2 capsule, respectively. The maximum melting and crystallization points in n-tetracosane@SiO2@Ag NPs (80 nm) were 51.05 and 43.27 °C, respectively, temperatures higher than those of pure n-tetracosane. The encapsulated n-tetracosane@SiO2@Ag NPs (80 nm) exhibited a fusing and freezing latent heat capacities of 170.51 and 169.07 J/g, respectively, an energy-storage efficiency of 63.41%, and a thermal storage capacity of 100%. Moreover, even with repeated fusing and freezing over 100 cycles, there was no significant change in the thermal energy storage capacity, and the shape of the capsules was maintained as it was. These results indicate that the encapsulated n-tetracosane@SiO2@Ag NPs have good thermal stability, which could be used as form–stabilized phase change materials for thermal energy storage.

Recently, the frenetic development of stable quaternary material with a wide range of solar energy absorption and separation of charge carrier has emerged as a favorable material for the solar-to-hydrogen conversion. In this work, quaternary CuS-AgVO3/Ag-TNR heteronanostructures (HNSs) synthesized by an ultra-sonication method for stabilized solar light photocatalytic hydrogen production in glycerol-water mixture. Among the prepared photocatalysts, the 1 wt% CuS-AgVO3/Ag-TNR HNS produced the highest H2 activity (756 µmol/g), approximately 84 times greater than the TNR due to higher charge separation, excellent conductivity, plasmonic resonance effect, and electron-storing capacity. Interestingly, the accelerated charge transfer pathway through the Schottky junction between the AgVO3 and Ag to the conduction band of the TNR and thereafter to the electron acceptor of CuS for the reduction of H+ ions to H2. Additionally, a possible photocatalytic mechanism of CuS-AgVO3/Ag-TNR HNS for improved H2 production was proposed based on the results obtained by various characterization techniques. Therefore, present research work explores the new insights to design high-performance CuS-AgVO3/Ag-TNR HNS material for the conversion of clean renewable H2 energy for the futuristic transport applications.

Designing the catalysts to achieve the best performance is no exception in carbon dioxide (CO2) solar fuel conversion. Herein, we designed a CuTiP/Au/CuTiP catalyst, wherein gold (Au) nanoparticles...

The purpose of the present work is to unveil the effect of very small amounts of Pt loaded onto a NiMn2O4 spinel catalyst on the chemical characteristics and catalytic activity for low-temperature steam reforming (LTSR) of propane. In the H2-TPR curves of the Pt-loaded catalysts, the reduction corresponding to Pt2+ → Pt0 occurred largely at approximately 200–350 °C. It is due to the high accumulation of hydrogen on the PtNi alloy. X-ray photoelectron spectroscopy measurements proved that the PtNi component acted as the active species. The catalysts with Pt loaded on 40NiMn2O4/60γ-Al2O3 show higher propane conversion due to the larger metal interface area created between Pt, Ni, and MnO. In particular, the 40Pt0.025NiMn2O4/60γ-Al2O3 catalyst maintained a very low amount of carbon deposition, a stable propane conversion of 100% and a hydrogen production capacity of 60% at 450 °C, even after 100 h of LTSR.

The exploration of proficient and stable H2 producing photocatalysts, specifically materials without noble metals, is highly anticipated, to initiate solar fuel generation for practical applications. Herein, novel CdS-Bi2MoO6 core–shell heterostructures (CdS-BMO CSHs) are prepared by a two-step solvothermal method, in which Bi2MoO6 nanosheets are grown on the surface of CdS nanorods. The resultant CdS-BMO CSHs display efficient charge separation and a low electron–hole recombination rate, promising excellent interfacial charge transfer properties. Meanwhile, the enhanced specific surface area and pore structure impart CdS-BMO CSHs with abundant active sites for the H2 evolution reaction. As a result, a heterojunction of CdS-BMO CSHs shows remarkable improvement in the photocatalytic H2 evolution reaction under visible light irradiation. The H2 evolution rate of optimized CdS-BMO CSHs is six times that of pristine CdS and ten times that of Bi2MoO6 nanosheets. This work could contribute to the further development of novel and highly efficient photocatalysts for the H2 evolution reaction.

Oxygen carrier particles were fabricated by using defected-MgMnAlO4 as a support particle with crystal defects, and by the Cu2+ ions with a higher reduction potential substituted with Mg2+ ions, in order to use methane-chemical looping combustion (CH4-CLC) reaction. The oxygen transfer capacities of the particles were compared when conducting redox reactions under H2/air or CH4-CO2/air systems. As a result, the oxygen transfer capacity increased as the amount of Cu ions added increased. In particular, in the CH4-CO2/air system, Cu0.75Mg0.25MnAlO4 particle showed an excellent oxygen transfer capacity of 7.62%. The XPS result confirms that the Cu2+ (also partially Mn3+ ions) in the Cu0.75Mg0.25MnAlO4 particle oxidize CH4, and then they are restored to their original state by receiving oxygen from the Al3+ and Mg2+ ions in the support. The oxygen vacancies in the lattice due to the Cu2+ could easily induce oxygen delivery, and the reversible oxygen loss recovery by re-oxidation in the air reactor could be achieved. This is the most important factor in increasing oxygen transfer capacity. Ultimately, in this study, oxygen defects in the crystal lattices induced during the reaction seem to have a positive effect on the CH4 combustion reaction.

Ternary heterostructures play a crucial role in improving the separation of charge carriers and fast surface reaction kinetics, which in turn helps in understanding the effective photocatalytic water splitting performance. Herein, CuS/Ag

This paper reports a simple method of designing and synthesizing magnetic iron oxide (IO) integrated locust bean gum-cl-polyacrylonitrile hydrogel nanocomposites (LBG-cl-PAN/IONP) by in situ mineralization of iron ions in a hydrogel matrix. A two-step gel crosslink method followed by co-precipitation method was used to prepare these novel hydrogels embedded with magnetic iron oxide nanoparticles. The LBG-cl-PAN/IONP hydrogel nanocomposite (HNC) were tested in batch adsorption experiments for their ability to remove a cationic dyes, methylene blue (MB)Methyl violet (MV), from aqueous solution. In order to analyze the LBG-cl-PAN/IONP HNC, FTIR, XRD, XPS, VSM, TEM, and EDX techniques were applied. Numerous operating parameters were studied, including the amount of adsorbent, the contact time, pH, temperature, the dye concentration, and the coexisting ion concentration. According to the Langmuir isotherm model, MB and MV had maximum monolayer adsorptive capacities of 1250 and 1111 mg/g, respectively. LBG-cl-PAN/IONP HNC controlled IONP oxidation as well as sustained adsorptive removal over a wide pH range (7-10). The key mechanism of adsorption consisted of electrostatic interaction and ion exchange. For successful use in successive cycles after regeneration using HNO

The minerals have a somewhat slower than other transition metals at critical reduction rates in their ability to deliver oxygen. Thus, single minerals alone do not exhibit a higher oxygen transfer capacity than metal oxide oxygen carriers. In this study, we try to solve the problem of single mineral ilmenite (FeTiO₃) by combining it with Fe-based red mud and Cu oxide. When the ilmenite was used without calcination, the CH₄-CO/air redox cycle showed rapid decayed. However, when ilmenite was calcined, the CH4-CO/air redox cycle became stable, and the oxygen transfer rate increased to 4.2%. This is because the FeTiO₃ structure was converted to the pseudobrookite (Fe₂TiO5) structure through the calcination process. That is, the Fe2+ ion in the ilmenite structure was converted into an Fe3+ ion. When 30 wt.% of red mud was added to the Fe ion, it reacted with the rutile-type titania mixed with pseudobrookite-typed Fe₂TiO5, producing an almost perfect pseudobrookite crystal. This resulted in a slight increase in the capacity of oxygen transfer to 4.9%. When 15 wt.% of Cu oxide was added, the oxygen transfer capacity increased to 6.0%. This performance was indicated by the cyclic voltammetry curve that remained constant even after 200 cycles. Here, we argue that if low-cost minerals as a base material are used in appropriate amounts, the production of a lowest-cost oxygen carrier can be achieved.

This study focuses on the improvement of oxygen transfer capacity of CuxMg1−xFeyTi2−yOz particle which simultaneously inserted with Cu2+ and Fe3+ ions into the Mg1.0Ti2.0O5.0 Karroite. The prepared Cu0.5Mg0.5Fe1.0Ti1.0O4.5 particle was composed of a co-mixture of a cubic Mg2TiO4 inverse spinel and an orthorhombic Fe2TiO5 Karroite. The CH4 and CO gases were selectively adsorbed on the surfaces of Cu and Fe ions, respectively, suggested that during the CLC, the Cu2+ and Fe3+ components had more effect to the methane combustion reaction and carbon monoxide oxidation. The oxygen transfer capacities of the Cu0.5Mg0.5Fe1.0Ti1.0O4.5 in the H2/air and CH4–CO2/air redox systems exhibited 9.59 % and 6.37 %, respectively. The difference of 3.22% in two systems corresponded to the affection of Fe2+. This work eventually revealed that when the Cu2+ and Fe3+ ions were simultaneously inserted for the Mg1.0Ti2.0O5.0 Karroite, their coexistence can improve the oxygen carrier capacity by a rapid oxygen migration through oxygen vacancies formed in lattice.

Porous Fe-oxalate complexes were prepared by thermally treating iron sources and rice husks under nitrogen gas purging. Fe oxidation states of 0, 2.5+, and 3+ in the complex were identified by X-ray photoelectron spectroscopy, which were oxidized into ferrites and separated by the magnet after removal of methyl orange. The Fe-oxalate complex treated at 700 °C exhibited the strongest magnetic properties, and its catalytic ability to remove 100 ppm of methyl orange was optimized after 60 min. In conclusion, the oxalate ions in Fe-oxalate complex could promote the decomposition of organic compounds accelerating the OH radical generation in a UV Fenton-like system.

Earth abundant metal based plasmonic photocatalysis is one of the most proficient approaches to degrade the emergent organic pollutants in contaminated water. Here, we report that using one-dimensional CdS/zero-dimensional Bi quantum dot (QD) heterostructures (1D/0D CdS/Bi HSs) were obtained via a simple solvothermal reaction. The results specified that the Bi QDs were grown onto CdS NRs through the reduction of Bi

Photocatalysis is a promising approach for generating hydrogen, an eco-friendly and cost-effective fuel. It is hypothesized that the ternary catalyst ZnIn

Photocatalytic removal is more appropriate for the destruction of organic contaminants. The ternary Bi