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This research successfully synthesized SnO2@ZnIn2S4 composites for photocatalytic tap water splitting using a rapid two-step microwave-assisted synthesis method. This study investigated the impact of incorporating a fixed quantity of SnO2 nanoparticles and combining them with various materials to form composites, aiming to enhance photocatalytic hydrogen production. Additionally, different weights of SnO2 nanoparticles were added to the ZnIn2S4 reaction precursor to prepare SnO2@ZnIn2S4 composites for photocatalytic hydrogen production. Notably, the photocatalytic efficiency of SnO2@ZnIn2S4 composites is substantially higher than that of pure SnO2 nanoparticles and ZnIn2S4 nanosheets: 17.9-fold and 6.3-fold, respectively. The enhancement is credited to the successful use of visible light and the facilitation of electron transfer across the heterojunction, leading to the efficient dissociation of electron–hole pairs. Additionally, evaluations of recyclability demonstrated the remarkable longevity of SnO2@ZnIn2S4 composites, maintaining high levels of photocatalytic hydrogen production over eight cycles without significant efficiency loss, indicating their impressive durability. This investigation presents a promising strategy for crafting and producing environmentally sustainable SnO2@ZnIn2S4 composites with prospective implementations in photocatalytic hydrogen generation. [ABSTRACT FROM AUTHOR]

The g-C3N4@ZnIn2S4 heterostructures were successfully synthesized through a combination of thermal annealing and hydrothermal methods. To enhance the photocatalytic hydrogen production performance and explore the interface between charge carriers, heterostructures of g-C3N4@ZnIn2S4 were fabricated using varying weights of g-C3N4 nanostructures under visible light irradiation. Remarkably, the photocatalytic hydrogen production efficiency of g-C3N4@ZnIn2S4 heterostructures with 0.01 g g-C3N4 nanostructures was significantly improved, showing approximately 228.6 and 2.58 times higher than that of g-C3N4 nanostructures and ZnIn2S4 nanostructures, respectively. This enhancement in photocatalytic performance is attributed to the effective utilization of visible light and the efficient separation of photogenerated electron-hole pairs facilitated by the heterojunction structures. Moreover, the reusability test validated the outstanding performance of g-C3N4@ZnIn2S4 heterostructures, as they maintained high photocatalytic hydrogen production even after undergoing eight cycles without any noticeable decrease in efficiency. This study offers a promising strategy for designing and synthesizing an environmentally friendly g-C3N4@ZnIn2S4 heterojunction with potential applications in photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this study, a facile and rapid microwave-assisted synthesis method was used to synthesize In2S3 nanosheets, ZnS nanosheets, and ZnIn2S4 nanosheets with sulfur vacancies. The two-dimensional semiconductor photocatalysts of ZnIn2S4 nanosheets were characterized by XRD, FESEM, BET, TEM, XPS, UV–vis diffuse reflectance, and PL spectroscopy. The ZnIn2S4 with sulfur vacancies exhibited an evident energy bandgap value of 2.82 eV, as determined by UV–visible diffuse reflectance spectroscopy, and its energy band diagram was obtained through the combination of XPS and energy bandgap values. ZnIn2S4 nanosheets exhibited about 33.3 and 16.6 times higher photocatalytic hydrogen production than In2S3 nanosheets and ZnS nanosheets, respectively, under visible-light irradiation. Various factors, including materials, sacrificial reagents, and pH values, were used to evaluate the influence of ZnIn2S4 nanosheets on photocatalytic hydrogen production. In addition, the ZnIn2S4 nanosheets revealed the highest photocatalytic hydrogen production from seawater, which was about 209.4 and 106.7 times higher than that of In2S3 nanosheets and ZnS nanosheets, respectively. The presence of sulfur vacancies in ZnIn2S4 nanosheets offers promising opportunities for developing highly efficient and stable photocatalysts for photocatalytic hydrogen production from seawater under visible-light irradiation. [ABSTRACT FROM AUTHOR]

We have demonstrated a two-step wet chemical approach for synthesizing ternary Ag/Ag2S/CdS heterostructures for efficient photocatalytic hydrogen evolution. The CdS precursor concentrations and reaction temperatures are crucial in determining the efficiency of photocatalytic water splitting under visible light excitation. In addition, the effect of operational parameters (such as the pH value, sacrificial reagents, reusability, water bases, and light sources) on the photocatalytic hydrogen production of Ag/Ag2S/CdS heterostructures was investigated. As a result, Ag/Ag2S/CdS heterostructures exhibited a 3.1-fold enhancement in photocatalytic activities compared to bare CdS nanoparticles. Furthermore, the combination of Ag, Ag2S, and CdS can significantly enhance light absorption and facilitate the separation and transport of photogenerated carriers through the surface plasma resonance (SPR) effect. Furthermore, the Ag/Ag2S/CdS heterostructures in seawater exhibited a pH value approximately 2.09 times higher than in de-ionized water without an adjusted pH value under visible light excitation. The ternary Ag/Ag2S/CdS heterostructures provide new potential for designing efficient and stable photocatalysts for photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

This study synthesized the In(OH) 3 –In 2 S 3 nanosheet via a simple hydrothermal method. The different amounts of In(OH) 3 –In 2 S 3 nanosheet used to synthesize In(OH) 3 –In 2 S 3 –Cu 2 O composite by a wet chemical method. FESEM, FETEM, XRD, XPS, BET, UV–vis DRS, and PL spectroscopy characterized the In(OH) 3 –In 2 S 3 –Cu 2 O composite. Compared with In(OH) 3 –In 2 S 3 nanosheet, In(OH) 3 –In 2 S 3 –Cu 2 O composite can exhibit the synergistic effects of higher specific surface area, higher light-harvesting capacity, and accelerating the separation and migration of photogenerated charge carriers. In addition, In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber was fabricated via a facile electrospinning process at the different amounts of In(OH) 3 –In 2 S 3 nanosheet. The manufacturing process offers many advantages, such as simplicity, low temperature, and without templates. The effect of operational parameters (such as the reaction conditions of photocatalysts, pH values, sacrificial reagents, and light sources) on the photocatalytic hydrogen production of In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber was investigated. The results indicate that the appropriate reaction conditions of In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber can reveal higher efficient photocatalytic water splitting than commercial TiO 2 or ZnO nanofiber under blue light LED excitation. Furthermore, In(OH) 3 –In 2 S 3 –Cu 2 O nanofiber can provide a simple fabrication process, high photocatalytic activity, and high reusability shall be beneficial for the practical application of photocatalytic hydrogen production. [Display omitted] • In 2 S 3 –In(OH) 3 –Cu 2 O nanofiber (NF) was prepared using the electrospinning method. • In 2 S 3 –In(OH) 3 –Cu 2 O NF exhibited enhanced photocatalytic activity for H 2 evolution. • The HER of In 2 S 3 –In(OH) 3 –Cu 2 O NF is 14.5 times higher than In(OH) 3 NF. • Cu 2 O nanoparticles can enhance charge-carries separation and transfer efficiency. • The mechanism for the photocatalytic H 2 production with In 2 S 3 –In(OH) 3 –Cu 2 O was explained. [ABSTRACT FROM AUTHOR]

In the present work, we described the synthesis and characterization of the ternary Cu2O/CuS/ZnS nanocomposite using a facile two-step wet chemical method for blue LED-light-induced photocatalytic hydrogen production. The concentrations of the ZnS precursor and reaction time were essential in controlling the photocatalytic hydrogen production efficiency of the Cu2O/CuS/ZnS nanocomposite under blue LED light irradiation. The optimized Cu2O/CuS/ZnS nanocomposite exhibited a maximum photocatalytic hydrogen evolution rate of 1109 µmolh−1g−1, which was remarkably higher than Cu2O nanostructures. Through the cycle stability it can be observed that the hydrogen production rate of the Cu2O/CuS/ZnS nanocomposite decreased after 4 cycles (1 cycle = 3 h), but it remained at 82.2% of the initial performance under blue LED light irradiation. These reasons are mainly attributed to the introduction of CuS and ZnS to construct a rationally coupled reaction system, which enables the synergistic utilization of photogenerated carriers and the increased absorption of visible light for boosting blue LED-light-driven photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

The novel ZnIn 2 S 4 /ZnO heterostructures can prepare by combining a facile hydrothermal and wet chemical methods. Various microscale and nanoscale characterization techniques analyzed the surface topography, structural and optical properties of the ZnIn 2 S 4 /ZnO heterostructures. The addition amount of ZnIn 2 S 4 nanosheets plays an essential role in controlling the optical properties of ZnIn 2 S 4 /ZnO heterostructures. ZnIn 2 S 4 /ZnO heterostructures can improve charge carriers separation and specific surface area for enhancing the photocatalytic decomposition of the 4-aminobenzoic acid solution and hydrogen evolution under blue LED irradiation. Furthermore, ZnIn 2 S 4 /ZnO heterostructures also revealed high photocatalytic stability and reusability for long-term reaction processes. Therefore, ZnIn 2 S 4 /ZnO heterostructures can be used as efficient visible-light-induced photocatalysts for the practical applications in water splitting and wastewater treatment. Image 1 • ZnO modified ZnIn 2 S 4 nanosheets were prepared by a wet chemical approach. • The heterostructures can greatly enhance visible-light hydrogen evolution activity. • The photodecomposition mechanism of PABA was mainly via h+ and ·OH radicals. • ZnIn 2 S 4 /ZnO heterostructures revealed excellent photocatalytic reusability and stability. [ABSTRACT FROM AUTHOR]

• Multistep processes can successfully synthesize the TiO 2 /NiS/Pt nanofiber (NF). • The TiO 2 /NiS/Pt NF exhibited enhanced photocatalytic activity for H 2 evolution. • The HER over the TiO 2 /NiS/Pt NF has 292 times increase over pure TiO 2 NF. • TiO 2 /NiS/Pt NF can lead to carriers' higher separation and transfer efficiency. • TiO 2 /NiS/Pt NF can provide practical application in seawater splitting. The porous TiO 2 nanofiber has been synthesized via facile electrospinning and thermal annealing. Furthermore, the intermediate layer of NiS and Pt nanoparticles can be sequentially deposited on the porous TiO 2 nanofiber to form hierarchical core-shell TiO 2 /NiS/Pt nanofiber through wet-chemical and self-assembly processes. Compared with the TiO 2 (16 µmolh−1g−1 L−1) nanofiber and TiO 2 /NiS nanofiber (54 µmolh−1g−1 L−1), TiO 2 /NiS/Pt nanofiber (4411 µmolh−1g−1 L−1) revealed remarkably photocatalytic activity for hydrogen evolution from water under visible light excitation. The significant enhancement in photocatalytic activity over the TiO 2 /NiS/Pt nanofiber could be attributed to enhanced visible light absorption and the separation of photogenerated electrons and holes. Furthermore, reusability experiments prove that TiO 2 /NiS/Pt nanofiber exhibits excellent stability for the long-term photocatalytic process. In addition, TiO 2 /NiS/Pt nanofiber can also use photocatalytic hydrogen production under different water bases. Therefore, this study provides a promising strategy to develop a novel heterostructure photocatalyst for highly efficient energy conversion. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 S 3 nanosheet synthesized via a facile hydrothermal method under the low reaction temperature. • The electrospinning method can use to fabricate ZnO-In 2 S 3 composite nanofiber (CP-NF). • ZnO-In 2 S 3 CP-NF exhibited a higher photocatalytic hydrogen evolution than ZnO NF. • ZnO-In 2 S 3 CP-NF revealed high-performance visible-light-induced photocatalysts. The zinc oxide-indium sulfide (ZnO-In 2 S 3) composite nanofiber has been fabricated via a convenient and straightforward electrospinning process without using templates, and these unique structures represent promising candidates for application in highly efficient hydrogen evolution photocatalyst. Mixing appropriate amounts of In 2 S 3 nanosheet into ZnO nanopowder to form ZnO-In 2 S 3 composite nanofiber can enhance photocatalytic hydrogen production activity. In addition, ZnO-In 2 S 3 composite can increase the separation of electron-hole pairs and the light absorption ability for progressing their photocatalytic hydrogen evolution under blue light-emitting diode (LED) irradiation. [ABSTRACT FROM AUTHOR]

• Iron-based oxygen carriers were pneumatically circulated and reacted in a 30-kW th moving bed chemical looping system. • The concentration of CO 2 produced in the reducer was 95%, and H 2 produced in the oxidizer reached 90%. • Oxygen carriers were nearly completely oxidized by air in the combustor resulting in temperature increase. • Parts of the oxygen carriers in the reducer were reduced to Fe, showing the integrating conversion rate of 61.5%. • In the oxidizer, the oxygen carrier contained Fe 3 O 4 , and the integrating conversion rate was 22.2%. A 30-kW th moving-bed chemical looping system has been developed at the Industrial Technology Research Institute of Taiwan. In this system, methane is supplied as a fuel to a reducer, and steam enters an oxidizer to produce hydrogen under ambient pressure. An iron-based oxygen carrier is used and pneumatically transported in the system. In this study, a hydrogen production test was performed on the system, while the methane flow rate was 40 L/min according to the capacity requirement of a 30-kW th system, and the oxygen carrier circulation rate was 2100 g/min for 40-wt% Fe 2 O 3 content. The concentration of carbon dioxide produced in the reducer was 95 %, and the concentration of hydrogen produced in the oxidizer reached 90 %. Partially oxidized oxygen carriers then reacted with air in the combustor, leading to a temperature increase of approximately 120°C. The oxygen carriers in the reducer were reduced to Fe, and the integrating conversion rate was 61.5 %. In the oxidizer, the oxygen carrier contained Fe 3 O 4 , and the integrated conversion rate was 22.2 %. 75 % of the oxygen carriers in the combustor exhibited a conversion rate of 5.3 %, indicating a nearly complete oxidation state. By conducting the hydrogen production test while effectively removing small particles of worn oxygen carriers from the system, the moving-bed chemical looping system was evaluated for the circulation and reaction of oxygen carriers. The system development experience will be used for system scale-up design. [ABSTRACT FROM AUTHOR]

A MoS 2 /graphene hybrid (MSG) is synthesized by microwave hydrothermal method. Both of the charge transfer resistance and the photocurrent are tuned in graphene modified MoS 2 by enhancing photocatalytic nature, where the charge transfer resistance significantly decreases from 36,000 Ω–8.49 Ω and the photocurrent promotes from 0.29 mA cm−2 to 16.47 mA cm−2. In this article, the result reveals that the appropriate modification of graphene can reach the maximum yield of hydrogen gas. In addition, the appropriate conditions, such as the concentration of 0.32 M formic acid and the MoS 2 photocatalyst with 0.8 wt% graphene (MSG 0.8) dose of 0.013 g L−1, can complete the outstanding photocatalytic hydrogen evolution, where the hydrogen evolution using MSG 0.8 composite photocatalyst has the maximum yield of 667.2 μmol h−1 g−1. Image 1 • Graphene modified MoS 2 could tune the charge transfer resistance and the photo current as well. • Formic acid acts as electron donor to capture photogenerated holes to improve hydrogen production. • MSG 0.8 has the maximum hydrogen evolution rate of 667.2 μmol h−1 g−1. [ABSTRACT FROM AUTHOR]