Bismuth-Metal and Carbon Quantum Dot Co-Doped NiAl-LDH Heterojunctions for Promoting the Photothermal Catalytic Reduction of CO2

The quest for sustainable photocatalytic CO2 reduction reactions (CRR) emphasizes the development of high-efficiency, economically viable, and durable photocatalysts. A novel approach involving the synthesis of Bi-CDs/LDH heterojunctions, incorporating plasma metals and carbon quantum dots via hydrothermal and co-precipitation methods, yields remarkable results. The optimized BCL-4 photocatalyst demonstrates exceptional performance, with C2H4 and C2H6 yields of 1.35 and 2.17 µmol g-1 h-1, respectively, representing substantial enhancements of 11.25 and 14.47 times compared to the LDH monomer. Moreover, the catalyst exhibits a notable selectivity of 36.6% for C2 products. Plasmonic Bi with high conductivity and carbon quantum dots synergistically enhances visible light absorption and generated additional hot electrons. The electron-trapping ability of carbon quantum dots is pivotal in creating elevated electron and CO2 concentrations at the catalyst interface, fostering conditions conducive to promoting C─C coupling reactions for the generation of C2 products.

Carbon-Dots-Modified Hierarchical ZnIn2S4/Ni-Al LDH Heterojunction with Boosted Charge Transfer for Visible-Light-Driven Photocatalytic H2 Evolution

The construction of a heterojunction structure is considered a significant route to promote solar-driven H₂ production. Herein, a CDs/ZnIn₂S₄/Ni-Al LDHs (CDZNA) ternary heterojunction was elaborately constructed via the in situ growth of ZnIn₂S₄ on Ni-Al LDHs with the incorporation of carbon dots (CDs) cocatalyst, which was used as a highly efficient catalyst for the photocatalytic H₂ generation. Characterizations indicated that 2D ZnIn₂S₄ nanosheet homogeneously dispersed on the surface of Ni-Al LDHs fabricated an intimate hierarchical architecture and provided a high BET surface area (135.12 m² g^-1). In addition, the unique embeddable-dispersed CDs as electron mediators possessed numerous active sites and promoted the charge separation on ZnIn₂S₄/Ni-Al LDHs (ZNA) binary catalyst. By coupling these two features, the CDZNA catalyst exhibited a considerable H₂ production rate of 23.1 mmol g^-1 h^-1 under visible-light illumination, which was 16.4 and 1.4 times higher than those of ZnIn₂S₄ and ZNA, respectively. A proposed mechanism of photocatalytic H₂ production over the CDZNA catalyst was also discussed. This work provides a promising strategy to achieve highly efficient solar energy conversion in a ternary photocatalytic system.

One-pot synthesis of Zn-CdS@C nanoarchitecture with improved photocatalytic performance toward antibiotic degradation

In this paper, carbon-coated Zn doped CdS core-shell photocatalyst (Zn-CdS@C) was fabricated via one-pot solvothermal method. The obtained Zn-CdS@C architectures displayed enhanced performance in photocatalytic antibiotic removal process. The Zn doped sites and carbon shell could all contribute to the prolonged lifetime of charge carriers and furthermore, result in the improved photoactivity. Moreover, the carbon shell could effectively improve the corrosion resistance of sulfide photocatalyst. We hope this study could provide novel insights into the fabrication of highly-efficient carbon-coated core-shell nanostructure toward wastewater treatment.

Bridging between NiAl-LDH and g-C3N4 by using carbon quantum dots for highly enhanced photoreduction of CO2 into CO

A series of treble NiAl-LDH/g-C₃N₄/carbon quantum dots (LDH/CN/CQDs) photocatalysts is successfully prepared for the photoreduction of CO₂ to CO via a facile hydrothermal pathway. In the 3D flower-like LDH/CN/CQDs, CQDs not only achieve the efficient inhibition of charge recombination but also act as the unhindered "electronic bridges" to synergistically construct a classical type-Ⅱ charge transfer configuration, which synchronously permits the effluence of photogenerated electrons from CN to LDH and holes from LDH to CN, and promotes ultraviolet-visible irradiation respondence. The sample of LDH/CN/CQDs-6 is the optimal one amongst the LDH/CN/CQDs with a larger special surface area (98.43 m²g^-1) and an appropriate content of CQDs (66.9 wt%), exhibiting the highest CO evolution rate (5.2 μmol·g^-1·h^-1) under visible light irradiation without any sacrificial agent or photosensitizer in water. This is 26.8- and 20.9-fold higher than those of the pristine LDH, pure CN, and their binary counterparts, respectively, and also outperforms most reported LDH-based photocatalysts. As unhindered electron conduction bridges, the highly dispersed CQDs in the LDH/CN heterojunction significantly increase utilization efficiency of light energy and separation efficiency of photogenerated electron-hole pairs. This work provides a beneficial attempt to integrate CQDs with LDH/CN for the positive synergetic effect on both photoelectric properties and electron transfer to obtain highly enhanced photocatalytic activity of CO₂ into CO, and expected to be extended towards broader photocatalytic applications.

Nano-flower S-scheme heterojunction NiAl-LDH/MoS2 for enhancing photocatalytic hydrogen production

The construction of heterojunctions can effectively improve the electron transport rate and photocatalytic activity.

Engineering a NiAl-LDH/CoSx S-Scheme heterojunction for enhanced photocatalytic hydrogen evolution

The use of semiconductors to construct heterojunctions to suppress the rapid recombination of photogenerated charges and holes is considered to be an effective way to improve the efficiency of photocatalytic hydrogen evolution. Herein, cobalt sulfide (CoS_x) nanoparticles are cultivated in situ in the folds of three-dimensional flower-like nickel-aluminium layered double hydroxides (NiAl-LDHs) using a facile solvothermal method. The hydrogen production rate of the binary CoS_x/NiAl-LDH heterojunction reaches 3678.59 μmol/g/h, which is 83.74 and 22 times the rates of CoS_x and NiAl-LDH, respectively. The unique three-dimensional structure of NiAl-LDH facilitates the growth of CoS_x and shortens the transfer pathway of photogenerated electrons. More importantly, the built-in electric field formed at the interface and the S-type charge transport mechanism caused by the bending of the energy band enhance not only charge separation but also maintain the strong oxidation ability of the holes. In this study, the newly designed S-scheme heterojunction offers a new strategy for enhancing photocatalytic water splitting.