Yangqin Gao

Rational engineering of plasmonic semiconductor heterostructures is pivotal for harvesting near-infrared (NIR) photons and driving efficient solar-to-hydrogen conversion.

Qualitative correlation between the nano-geometric arrangements of BiOI films and photon utilization efficiency elucidates a morphology regulated crystal facet effect.

While constructing heterojunctions is a pivotal strategy for directing charge carrier separation to boost photocatalytic performance, a systematic understanding of their intrinsic mechanisms remains elusive. This limitation stems from the difficulty of independently manipulating the properties of individual components in conventional powder-derived thin-film photocatalysts. In this work, we address this challenge by adopting a gas-liquid interfacial strategy for thin-film photocatalyst growth and subsequent heterojunction construction through a water interlayer-assisted layer stacking protocol. This approach enables the facile assembly of well-defined heterojunctions without compromising the intrinsic properties of each constituent layer. The resulting heterojunction thin-film photocatalysts, composed of sequentially stacked BiOBr and BiOI layers, exhibit markedly enhanced directional charge separation. Their photocatalytic NO removal performance is highly dependent on the thickness and morphology of each layer. Systematic analysis reveals that the photocatalytic performance correlates with both the buried depth of the heterojunction interface and the interfacial contact density, offering key insights into rational heterojunction design. Moreover, the performance is also strongly influenced by the stacking sequence of the constituent layers, highlighting that aligning the directional charge separation process with other directional physical processes, such as mass transfer within porous networks, is crucial for achieving enhanced overall photocatalytic performance for NO removal.

The development of ultrablack coatings with exceptional absorption (>98%) has historically faced significant scientific and engineering challenges, primarily due to limitations in material selection, structural design, and practical durability. Considering the difficulties in practical applications of ultrablack materials with micro/nano structures and the limitations of planar ultrablack coatings in optical performance, we introduce an innovative integration of conventional planar ultrablack coatings with a specifically engineered trilayer antireflection architecture. This hybrid system incorporates a refractive index distribution (1.6-1.8-1.3 from substrate to air interface) achieved through a "dry-wet hybrid" deposition methodology. This coating exhibits outstanding optical performance, achieving 99.1% average visible-light absorption and peak absorption reaching 99.9%, which is in excellent agreement with theoretical simulations. The hybrid fabrication strategy offers dual advantages: it maintains antireflection performance comparable to vacuum-deposited coatings while significantly enhancing mechanical robustness. After 20,000 bending cycles, the coating retains optical stability with less than 1% performance degradation, showing no delamination or microcracking. A subsequent SiO₂ chemical vapor deposition (5 nm) further improves surface durability, limiting optical loss to less than 0.5% while achieving tribological properties on par with those of commercial antireflective films. In addition, it also exhibits a remarkable ability to convert light into heat and is resistant to high temperatures and acid erosion. This breakthrough combines unparalleled optical performance with excellent mechanical properties, demonstrating substantial potential for advanced optical applications such as stray light suppression and photothermal conversion. The dry-wet hybrid approach establishes a paradigm for developing multifunctional optical coatings that surpass traditional single performance.

The photocatalytic removal of nitric oxide (NO) is a promising technology used to reduce the level of harmful gaseous pollutants in parts per billion (ppb). As a potential photocatalyst, Bi₂Sn₂O₇ has a low quantum efficiency due to its fast recombination rate of photo-generated carriers. In this paper, Bi/Bi₂Sn₂O₇ was prepared by the in situ deposition of Bi. The structural, electrical, and optical properties of the attained sample were investigated through a series of analyses. The results demonstrate that Bi nanoparticles not only enhance the photoabsorption ability of Bi₂Sn₂O₇ due to their surface plasmon resonance (SPR) effect, but also improve its photocatalytic activity. Photocatalytic performance was evaluated by the oxidation of NO at ppb level under xenon lamp (λ > 400 nm) irradiation. It was found that the photocatalytic NO removal rate increased from 7.2% (Bi₂Sn₂O₇) to 38.6% (Bi/Bi₂Sn₂O₇). The loading of Bi promotes the separation and migration of photo-generated carriers and enhances the generation of •O²⁻ and •OH radicals responsible for the oxidation of NO. The Bi/Bi₂Sn₂O₇ composite photocatalyst also exhibits excellent photocatalytic stability, which makes it a potential candidate for use in air purification systems.

Photocatalysts with hollow structures have drawn great interest owing to their high specific surface area, which can enhance the photocatalytic performance. Herein, we designed the hollow cubic Cu2-xS@Ni-Mo-S nanocomposites by vulcanizing from the Cu2O template and loading the Ni-Mo-S lamellas. The Cu2-xS@Ni-Mo-S composites greatly improved the photocatalytic hydrogen performance. Among them, Cu2-xS-NiMo-5 achieved the optimal photocatalytic rate of 1326.07 mu mol/g h, which is approximately 3.85 times higher than that of hollow Cu2-xS (344 mu mol/g h) and had good stability for 16 h. The enhanced photocatalytic property was attributed to the metallic behavior of bimetallic Ni-Mo-S lamellas and the LSPR (localized surface plasmon resonance) effect of Cu2-xS. The bimetallic Ni-Mo- S can effectively capture the photogenerated electrons and quickly transfer-diffuse to produce H2. Meanwhile, the hollow Cu2-xS not only provided many more active sites to take part in the reaction but also introduced the LSPR effect to increase the solar utilization. This work provides valuable insights into the synergistic effect of using non-precious metal co-catalysts and the LSPR materials to assist in the photocatalytic hydrogen evolution.