Weiping Huang

Compared with a single semiconductor, the heterojunction formed by two different semiconductors usually has higher light utilization and better photoelectric performance. By using stable TiO₂ nanotubes as the main subject, CdSe/TiO₂NTs heterojunctions were synthesized by a hydrothermal method. XRD, TEM, SEM, PL, UV-vis, and EIS were used to characterize the fabricated CdSe/TiO₂NTs. Under visible light irradiation, CdSe/TiO₂NTs heterojunctions exhibited a higher absorption intensity and lower degree of photogenerated carrier recombination than TiO₂. The electrons and holes were proven to be effectively separated in this heterojunction via theoretical calculation. Under CdSe/TiO₂NTs' optimal conditions, the glucose concentrations (10-90 μM) had a linear relationship with the photocurrent value, and the detection limit was 3.1 μM. Moreover, the CdSe/TiO₂NTs sensor exhibited good selectivity and stability. Based on the experimental data and theoretical calculations, its PEC sensing mechanism was also illuminated.

The formation of heterojunction structures can effectively prevent the recombination of photogenerated electron–hole pairs in semiconductors and result in the enhancement of photoelectric properties. Using TiO₂ nanotubes (prepared using the hydrothermal-impregnation method) as carriers, CdS-TiO₂NTs were fabricated as a photoelectrochemical (PEC) sensor, which can be used under visible light and can exhibit good PEC performance due to the existence of the heterojunction structure. The experimental results show that the prepared CdS-TiO₂NTs electrode had a linear response to 2–16 mM glutathione (GSH). The sensor’s sensitivity and detection limit (LOD) were 102.9 µA·mM⁻¹ cm⁻² and 27.7 µM, respectively. Moreover, the biosensor had good stability, indicating the potential application of this kind of heterojunction PEC biosensor.

This paper studies a transferable phoneme embedding framework that aims to deal with the cross-lingual text-to-speech (TTS) problem under the few-shot setting. Transfer learning is a common approach when it comes to few-shot learning since training from scratch on few-shot training data is bound to overfit. Still, we find that the naive transfer learning approach fails to adapt to unseen languages under extremely few-shot settings, where less than 8 minutes of data is provided. We deal with the problem by proposing a framework that consists of a phoneme-based TTS model and a codebook module to project phonemes from different languages into a learned latent space. Furthermore, by utilizing phoneme-level averaged self-supervised learned features, we effectively improve the quality of synthesized speeches. Experiments show that using 4 utterances, which is about 30 seconds of data, is enough to synthesize intelligible speech when adapting to an unseen language using our framework.

In today’s age of resource scarcity, the low-cost development and utilization of renewable energy, e.g., hydrogen energy, have attracted much attention in the world. In this work, cheap natural halloysite nanotubes (HNTs) were modified with γ-aminopropyltriethoxysilane (APTES), and the functionalized HNTs were used as to support metal (Pd, Au, Ag) catalysts for dehydrogenation of formic acid (DFA). The supports and fabricated catalysts were characterized with ICP, FT-IR, XRD, XPS and TEM. The functional groups facilitate the anchoring of metal particles to the supports, which brings about the high dispersion of metallic particles in catalysts. The catalysts show high activity against DFA and exhibit selectivity of 100% toward H₂ at room temperature or less. The interactions between active centers and supports were investigated by evaluation and comparison of the catalytic performances of Pd/NH₂-HNTs, PdAg/NH₂-HNTs and PdAu/NH₂-HNTs for DFA.

Based on the enhanced charge separation efficiency of the one-dimensional structure and strong surface plasmon resonance (SPR) of gold, a gold modified TiO₂ nanotube (Au/TiO₂NTs) glucose photoelectrochemical (PEC) sensor was prepared. It could be activated by visible red light (625 nm). Under optimal conditions, the Au/TiO₂NTs sensor exhibited a good sensitivity of 170.37 μA·mM⁻¹·cm⁻² in the range of 1–90 μM (R² = 0.9993), and a detection limit of 1.3 μM (S/N = 3). Due to its high selectivity, good anti-interference ability, and long-term stability, the fabricated Au/TiO₂NTs sensor provides practical detection of glucose. It is expected to be used in the construction of non-invasive PEC biosensors.

Photocatalytic water splitting for hydrogen generation is a significant pathway for sustainable energy conversion and production. The photocatalysts with a Z-scheme water splitting charge transfer pathway is superior due to the good separation and migration ability of photoexcited charge carriers. Herein, Co₃O₄/g-C₃N₄ photocatalysts with Z-scheme charge transfer pathway were successfully constructed by an electrostatic interaction-annealing method. The as-prepared Co₃O₄/g-C₃N₄ ultra-thin nanosheets were tested and analyzed by XRD, EA, ICP, SEM, TEM, AFM, XPS, UV-Vis DRS, PL and photoelectrochemical measurements. Moreover, the influences of fabrication parameters on performance of Co₃O₄/g-C₃N₄ catalysts were investigated, and 0.5% Co₃O₄/g-C₃N₄ exhibited the optimal activity. Based on the characterization and catalytic performance, the Z-scheme charge transfer pathway of Co₃O₄/g-C₃N₄ was established and put forward. To further improve the catalytic performance of Co₃O₄/g-C₃N₄, 0.5% Pt was added as a co-catalyst. The obtained Pt/0.5% Co₃O₄/g-C₃N₄ was recyclable and remained the original catalytic water splitting performance within 20 h. The modification of Co₃O₄ and Pt improved the separation and migration of e⁻ and h⁺, and induced the increased hydrogen evolution rate of g-C₃N₄.

The hydroformylation of alkenes with CO and H₂ to manufacture aldehydes is one of the most large-scale chemical reactions. However, an efficient and recyclable heterogeneous catalyst for alkene hydroformylation is extremely in demand in academia and industry. In this study, a sulfated carbon nitride supported rhodium particle catalyst (Rh/S-g-C₃N₄) was successfully synthesized via an impregnation-borohydride reduction method and applied in the hydroformylation of alkenes. The catalysts were characterized by XRD, FTIR, SEM, TEM, XPS, and nitrogen adsorption. The influence of the sulfate content, pressure of syngas, temperature, and reaction time, as well as the stability of Rh/S-g-C₃N₄, on the hydroformylation was examined in detail. The delocalized conjugated structure in g-C₃N₄ can lead to the formation of electron-deficient aromatic intermediates with alkenes. The sulphate g-C₃N₄ has a defected surface owing to the formation of oxygen vacancies, which increased the adsorption and dispersion of RhNPs on the surface of g-C₃N₄. Therefore, Rh/S-g-C₃N₄ exhibited an outstanding catalytic performance for styrene hydroformylation (TOF = 9000 h⁻¹), the conversion of styrene could reach 99.9%, and the regioselectivity for the branched aldehyde was 52% under the optimized reaction conditions. The catalytic properties of Rh/S-g-C₃N₄ were also studied in the hydroformylation of various alkenes and displayed an excellent catalytic performance. Furthermore, the reuse of Rh/S-g-C₃N₄ was tested for five recycling processes, without an obvious decrease in the activity and selectivity under the optimum reaction conditions. These findings demonstrated that Rh/S-g-C₃N₄ is a potential catalyst for heterogeneous hydroformylation.