Liqun Bai

Photocatalysis is one of the most promising pathways to relieve the environmental contamination caused by the rapid development of modern technology. In this work, we demonstrate a green manufacturing process for the 3D/3D rod-shaped bamboo charcoal/Bi₂WO₆ photocatalyst (210BC-BWO) by controlled carbonization temperature. A series of morphology characterization and properties investigations (XRD, SEM, UV–vis DRS, transient photocurrent response, N₂ absorption-desorption isotherms) indicate a 210BC-BWO photocatalyst with higher charge separation efficiency, larger surface area, and better adsorption capacity. The excellent photocatalytic performance was evaluated by degrading rhodamine B (RhB) (98.5%), tetracycline hydrochloride (TC-HCl) (77.1%), and H₂ evolution (2833 μmol·g⁻¹·h⁻¹) coupled with furfuryl alcohol oxidation (3097 μmol·g⁻¹·h⁻¹) under visible light irradiation. In addition, the possible mechanisms for degradation of organic pollutants, H₂ evolution, and furfuryl alcohol oxidation were schematically investigated, which make it possible to exert photocatalysis by increasing the active radical. This study shows that the combination of bamboo charcoal and bismuth tungstate can be a powerful photocatalyst that rationally combines H₂ evolution coupled with furfuryl alcohol oxidation and degradation of pollutants.

In this work, a novel two-dimensional/two-dimensional (2D/2D) hybrid photocatalyst consisting of Bi₂WO₆ (BWO) nanosheets and cotton fibers biochar (CFB) nanosheets was successfully prepared via a facile hydrothermal process. The as-prepared photocatalysts were characterized by a variety of techniques, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectroscopy. It was revealed that amorphous CFB nanosheets were uniformly immobilized on the surface of crystalline BWO nanosheets, and an intimate contact between CFB and BWO was constructed. The photocatalytic activities of the prepared BWO and CFB-BWO photocatalysts were evaluated by photocatalytic degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC-HCl) in aqueous solutions under visible-light irradiation. Compared to the pristine BWO, the CFB-BWO composite photocatalysts exhibited significant enhancement in photocatalytic activities. Among all CFB-BWO samples, the 9CFB-BWO sample with the CFB mass ratio of 9% exhibited optimal photocatalytic activities for RhB or TC-HCl degradation, which was ca. 1.8 times or 2.4 times that of the pristine BWO, respectively. The improvement in photocatalytic activities of the CFB-BWO photocatalysts could be ascribed to the enhanced migration and separation of photogenerated charge carriers due to the formation of a 2D/2D interfacial heterostructure between CFB and BWO. Meanwhile, the possible mechanism of CFB-BWO for enhanced photocatalytic performance was also discussed. This work may provide a new approach to designing and developing novel BWO-based photocatalysts for the highly efficient removal of organic pollutants.

As a ferroelectric material with spontaneous polarization, BiFeO₃ (BFO) has been considered as a promising photoelectrode material in recent years, but its photoelectrochemical (PEC) properties still need to be further improved. In this work, the Au/Nd-doped BFO (Au/BNFO) thin film photoelectrode was successfully fabricated by combining Au nanoparticle (NP) loading and Nd doping, aiming to improve the PEC performance of the BFO photoelectrode. To fabricate the Au/BNFO thin film photoelectrodes, the BNFO thin film was first prepared by sol–gel spin coating and Au NPs were then photodeposited on the surface of the BNFO thin film. The PEC test results reveal that the photocurrent density of Au/BNFO at 1.2 V (vs. Ag/AgCl) was 0.63 mA cm⁻², which was much higher than pure BFO (0.13 mA cm⁻²), BNFO (0.17 mA cm⁻²) and Au/BFO (0.31 mA cm⁻²), and the transient photocurrent density measured upon on–off light illumination was ca. 3.8, 1.8 and 1.2 times that of BFO, BNFO and Au/BFO, respectively. This indicates that the PEC properties of the BFO photoelectrode could be greatly improved by the synergistic effect of Au NP loading and Nd doping. The improved PEC properties of the Au/Nd–BiFeO₃ photoelectrode could be attributed to the synergistic effect of the combination of Au NPs and Nd doping, which could increase the carrier concentration, promote the charge separation and inhibit the recombination of photogenerated carriers, as confirmed by the Mott–Schottky (MS), electrochemical impedance spectra (EIS) and photoluminescence (PL) spectra.

Bursaphelenchus xylophilus is a notorious invasive species, causing extensive losses to pine ecosystems globally. Previous studies had shown that the development of B. xylophilus was seriously suppressed by light. However, the mechanism involved in the inhibition is unknown. Here, it is the first report that Bxy-madd-4 is a light-regulated gene, plays a potential role in B. xylophilus in responding to the blue light. Transcriptome sequencing revealed that the expression level of Bxy-madd-4 declined by 86.39% under blue light. The reverse transcription quantitative real-time PCR results were in accord with the transcriptome sequencing, confirming the expression level of Bxy-madd-4 was suppressed by blue light. Bxy-madd-4 promoter::mCherry reporter constructed in Caenorhabditis elegans were utilized to mimic the spatiotemporal expression patterns of Bxy-madd-4. Bxy-madd-4A promoter activity had a strong continuity throughout all development stages in C. elegans. Further RNA interference indicated that only 36.8% of the Bxy-madd-4 dsRNA treated embryos were hatched. Moreover, 71.6% of the hatched nematodes were abnormal, such as particles on the body surface and concave tissues. Our findings contribute towards a better understanding of the mechanism of light against the destructive invasive nematode, providing a promising hint for control of the destructive invasive nematode.

Bursaphelenchus xylophilus is the causal agent of pine wilt disease, which leads to the devastation of millions of hectares of pine trees worldwide. Protein kinase B (AKT) is a structurally conserved serine/threonine kinase with a pleckstrin homology domain and a kinase domain, and it plays versatile biological roles across different animal kingdoms. We, therefore, investigated the molecular characteristics and biological function of akt‐1 in B. xylophilus (Bxy‐akt‐1). In propagative stages, reverse transcription quantitative real‐time PCR revealed that Bxy‐akt‐1 expression gradually increased during embryogenesis, reaching the highest level at the second‐stage juvenile (J2), and then steadily decreased from J3 to adults. Intriguingly, the expression of Bxy‐akt‐1 was significantly higher in males than in females. Moreover, the expression level of Bxy‐akt‐1 in dispersal third‐stage dauer larvae (DL3) was higher than that in J2, but it decreased to normal level in DL4. Bxy‐akt‐1 promoter::gfp reporter constructed in Caenorhabditis elegans was utilized to mimic the spatio‐temporal expression pattern of Bxy‐akt‐1. The results showed that Bxy‐akt‐1 was broadly expressed in the hypodermis around the head during embryogenesis and was mainly expressed in the muscle cells of pharynx, vulva, tail and nerve systems in post‐embryonic stages. Abnormal embryos were observed, and the hatching rate was significantly decreased after Bxy‐akt‐1 was knocked down in B. xylophilus, but no constitutive developmental arrest of dauer larvae was observed. The results indicated that Bxy‐akt‐1 is indispensable for embryogenesis, but might not play a significant role in controlling dauer entry, as in C. elegans.

To understand the efficacy of emamectin benzoate, avermectin, milbemectin, and thiacloprid on the reproduction and development of Bursaphelenchus xylophilus, seven parameters, namely population growth, fecundity, egg hatchability, larval lethality, percent larval development, body size, and sexual ratio, were investigated using sublethal (LC20) doses of these compounds in the laboratory. Emamectin benzoate treatment led to a significant suppression in population size, brood size, and percent larval development with 411, 3.50, and 49.63%, respectively, compared to 20850, 24.33, and 61.43% for the negative control. The embryonic and larval lethality increased obviously from 12.47% and 13.70% to 51.37% and 75.30%, respectively. In addition, the body length was also significantly reduced for both males and females in the emamectin benzoate treatment. Avermectin and milbemectin were also effective in suppressing population growth by increasing larval lethality and reducing larval development, although they did not affect either brood size or embryonic lethality. Body length for both male and female worms was increased by avermectin. Thiacloprid caused no adverse reproductive effects, although it suppressed larval development. Sexual ratio was not affected by any of these four nematicides. Our results indicate that emamectin benzoate, milbemectin, and avermectin are effective against the reproduction of B. xylophilus. We think these three nematicides can be useful for the control of pine wilt disease.