Leaf-inspired structural design of artificial leaf BiVO4/InVO4 heterojunction with enhanced photocatalytic activity for pollutant degradation

Integration of high visible-light-driven ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction nanocomposite for enhanced uranium(VI) photoreduction separation

With deepening application of nuclear power technology, the problem of water ecological environment pollution caused by uranium (U(VI)) is becoming increasingly serious. Photoreduction separation of U(VI) on photocatalysts is considered as an effective strategy to solve uranium pollution. In this work, a novel ternary dual Z-scheme AgVO3-InVO4/g-C3N4 heterojunction (Z-AIGH) nanocomposite with high surface area (73.45 m2 g-1, Z-AIGH2) was designed. The batch adsorption experiment in dark environment showed that Z-AIGH2 nanocomposite had an excellent U(VI) adsorption performance. As for photocatalytic experiments, Z-AIGH2 exhibited a rapid photocatalytic response for separating U(VI) without any organic sacrifice agents. The U(VI) separation rate on Z-AIGH2 nanocomposite was over 98.7% after only 20.0 min visible light irradiation (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). Z-AIGH2 nanocomposite also showed good selectivity and cycle stability. The U(VI) removal rate of Z-AIGH2 nanocomposite after fifth cycles was about 96.1% (T = 298 K, CU(Ⅵ) = 10.0 mg L-1, m/V = 0.1 g L-1 and pH = 7.0). High photocatalytic activity of Z-AIGH2 for U(VI) was attributed to the construction of ternary dual Z-scheme heterojunction structure and ant nest-like hole structure. Based on above results, Z-AIGH2 nanocomposite had great potential for water environment renovation.

Omnidirectional Hydrogen Generation Based on a Flexible Black Gold Nanotube Array

Solar-driven hydrogen generation is emerging as an economical and sustainable means of producing renewable energy. However, current photocatalysts for hydrogen generation are mostly powder-based or rigid-substrate-supported, which suffer from limitations, such as difficulties in catalyst regeneration or poor omnidirectional light-harvesting. Here, we report a two-dimensional (2D) flexible photocatalyst based on elastomer-supported black gold nanotube (GNT) arrays with conformal CdS coating and Pt decoration. The highly porous GNT arrays display a strong light-trapping effect, leading to near-complete absorption over almost the entire range of the solar spectrum. In addition, they offer high surface-to-volume ratios promoting efficient photocatalytic reactions. These structural features result in high H₂ generation efficiencies. Importantly, our elastomer-supported photocatalyst displays comparable photocatalytic activity even when being mechanically deformed, including bending, stretching, and twisting. We further designed a three-dimensional (3D) tree-like flexible photocatalytic system to mimic Nature's photosynthesis, which demonstrated omnidirectional H₂ generation. We believe our strategy represents a promising route in designing next-generation solar-to-fuel systems that rival natural plants.

CdS-based artificial leaf for photocatalytic hydrogen evolution and simultaneous degradation of biological wastewater

Rational design of all-solid-state Z-scheme heterojunction with advanced structure is essential for boosting photocatalytic efficiency. Herein, we design and fabricate a novel Z-scheme photocatalyst with leaf architecture (named artificial leaf) via a simple dipping-calcination (DC) process followed by a successive ionic layer adsorption and reaction (SILAR) strategy. The prepared artificial leaf, composing of CdS, InVO₄, and BiVO₄, holds advanced leaf-like structure and Z-scheme electron transfer pathway. As a result, this novel artificial leaf exhibits outstanding capability for the harvesting of visible light and superior efficiency for the separation of photogenerated electron-hole pairs, as well as remarkably enhanced photocatalytic performance and stability for H₂ evolution (with the rate of 5033 μm g^-1∙h^-1) and pollution degradation (46% pollution can be degraded within 3 h).

Facile synthesizing Z-scheme Bi12O15Cl6/InVO4 heterojunction to effectively degrade pollutants and antibacterial under light-emitting diode light

The design of a photocatalytic system with Z-scheme heterojunction is the key to charge separation. In this paper, a simple synthesis method was used to prepare Bi₁₂O₁₅Cl₆/InVO₄ photocatalyst. The synthesized photocatalyst can effectively degrade pollutants, and inactivate bacteria under LED light irradiation. The optimal ratio of 30% Bi₁₂O₁₅Cl₆/InVO₄ material effectively degraded 78.85% of TC and 97.83% of RhB within 90 min and inactivated Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 40 min. This improvement in photocatalytic performance is mainly due to the formation of a Z-scheme heterojunction between Bi₁₂O₁₅Cl₆ and InVO₄, which produces effective charge separation and improves photocatalytic degradation and antibacterial activity. The capture experiment revealed the main active substances. The effects of catalyst dosage and pollutant concentration were investigated in details. The intermediates of TC degradation were identified by mass spectrometry (MS), and the possible photocatalytic degradation pathway was proposed. Capture experiment and related measurements proposed the Z-scheme mechanism. This work emphasizes the importance of heterogeneous structure construction and proposes feasible solutions for the rational design of catalysts with photodegradation and antibacterial properties under LED light.

Visible-light-driven indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes heterostructure as an efficient photocatalyst for the tetracycline degradation

The development of excellent photocatalysts is of great significance for the efficient photocatalytic degradation process, however, the low carrier separation efficiency and poor light absorption ability typically limit the performance of photocatalysts. Herein, a visible light responsive heterostructure composed with indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes (InVO₄/Bi₂WO₆) was synthetized through in-situ hydrothermal method. Further, the photocatalytic activity was performed for tetracycline (TC) under visible light illumination. The InVO₄/Bi₂WO₆ heterostructure builds a strong interface between InVO₄ and Bi₂WO₆ to hinder reunion of photoinduced charge carriers, and provides the sensitive agents for the removal of TC. In particular, the InVO₄/Bi₂WO₆ photocatalyst prepared by taking 5.0 mg of Bi₂WO₆ shows the highest degradation of TC about 97.42% in 72 min. The quenching experiments identified that hydroxyl radicals, and holes dominated in the photocatalytic process. Furthermore, the optimized nanocomposite is stable even after four cycles, which exposes the excellent photostability and reusability of the photocatalyst. In addition, a plausible degradation pathway and mechanism of TC over InVO₄/Bi₂WO₆ nanocomposite is also projected.

Investigation on Al3+ and Al2O3 Coexist in BiVO4 for Efficient Methylene Blue Degradation: Insight into Surface States and Charge Separation

A series of Al-doped BiVO₄ composites have been synthesized via the hydrothermal method for methylene blue (MB) degradation application. The reasons for the improvement of photocatalytic performance was explained from the perspective of optics. Transient photovoltage (TPV) measurements suggested that the surface states have the priority to capture photogenerated carriers, and the Al₂O₃ surface passivation layer can prolong the lifetime of charge carrier. The results of surface photovoltage (SPV), transient photovoltage (TPV), and surface photocurrent (SPC) measurements suggested that the coexistence of Al³⁺ and Al₂O₃ caused by the appropriate doping would improve the transfer property and prolong the lifetime of photogenerated carriers. Finally, the possible photocatalytic mechanism is expounded to illustrate the photogenerated charge behavior under visible light irradiation. This work provides a better understanding of the synergistic effect of Al-doping and Al₂O₃ passivation layer on enhancing the photocatalytic performance.