Efficient solar‐to‐hydrogen (STH) energy conversion under ambient conditions (room temperature and atmospheric pressure) is important for pursuing scalable solar hydrogen generation. Modification of ...polymeric carbon nitride (PCN) by conjugated polymers has attracted great attention for improving photocatalytic hydrogen evolution (PHE) performance. However, the limited interfacial junction between PCN and conjugated polymers leads to a low density of free charges, resulting in unsatisfactory PHE activity. Herein, three donor‐π‐acceptor‐structured organic molecules (OMs) with different electron‐donating units (amino, N,N‐diethyl and triphenylamine) and same electron‐accepting unit (benzothiadiazole) are designed to modify PCN to enlarge the interfacial junction. The optimized PHE performance under AM 1.5G simulated sunlight and ambient conditions can maintain as high as 4.63 mmol h−1 g−1 (the highest record among all the reported PCN‐based photocatalysts to the best of the authors knowledge). The improved performance can be partially attributed to the strong visible light harvesting capability of OMs. Specifically, the triphenylamine unit in the formed type II molecule heterojunctions (MHJ) enables efficient charge separation at the interfacial junction, which prolongs the photogenerated electron lifetime for PHE. The designed MHJ photocatalysts show outstanding PHE performance under ambient conditions, which is highly promising for scalable STH conversion.
Type II molecule heterojunctions (MHJ) with large interfacial junctions are obtained by integrating donor‐π‐acceptor‐structured organic molecules with polymeric carbon nitride (PCN). This MHJ delivers superior photocatalytic hydrogen evolution (PHE) performance (4.63 mmol h−1 g−1) under ambient conditions, which is the highest among all reported PCN‐based photocatalysts. The outstanding PHE performance under ambient conditions of the MHJ makes it promising for scalable solar‐to‐hydrogen conversion.
Abstract
The design of efficient and stable photocatalysts for robust CO
2
reduction without sacrifice reagent or extra photosensitizer is still challenging. Herein, a single-atom catalyst of ...isolated single atom cobalt incorporated into Bi
3
O
4
Br atomic layers is successfully prepared. The cobalt single atoms in the Bi
3
O
4
Br favors the charge transition, carrier separation, CO
2
adsorption and activation. It can lower the CO
2
activation energy barrier through stabilizing the COOH* intermediates and tune the rate-limiting step from the formation of adsorbed intermediate COOH* to be CO* desorption. Taking advantage of cobalt single atoms and two-dimensional ultrathin Bi
3
O
4
Br atomic layers, the optimized catalyst can perform light-driven CO
2
reduction with a selective CO formation rate of 107.1 µmol g
−1
h
−1
, roughly 4 and 32 times higher than that of atomic layer Bi
3
O
4
Br and bulk Bi
3
O
4
Br, respectively.
Solar photocatalysis is a potential solution to satisfying energy demand and its resulting environmental impact. However, the low electron–hole separation efficiency in semiconductors has slowed the ...development of this technology. The effect of defects on electron–hole separation is not always clear. A model atomically thin structure of single‐unit‐cell Bi3O4Br nanosheets with surface defects is proposed to boost photocatalytic efficiency by simultaneously promoting bulk‐ and surface‐charge separation. Defect‐rich single‐unit‐cell Bi3O4Br displays 4.9 and 30.9 times enhanced photocatalytic hydrogen evolution and nitrogen fixation activity, respectively, than bulk Bi3O4Br. After the preparation of single‐unit‐cell structure, the bismuth defects are controlled to tune the oxygen defects. Benefiting from the unique single‐unit‐cell architecture and defects, the local atomic arrangement and electronic structure are tuned so as to greatly increase the charge separation efficiency and subsequently boost photocatalytic activity. This strategy provides an accessible pathway for next‐generation photocatalysts.
Single‐unit‐cell Bi3O4Br nanosheets with both bismuth and oxygen defects are controllably prepared. These engineered surface defects can effectively tune the local atomic arrangement and electronic structure so as to greatly increase the charge‐separation efficiency. Benefiting from these features, defect‐rich single‐unit‐cell Bi3O4Br displays 4.9 and 30.9 times enhanced photocatalytic hydrogen evolution and nitrogen fixation activity, respectively, over bulk Bi3O4Br.
As one of the most used phthalates, Di (2-ethylhexyl) phthalate (DEHP) is a widespread environmental contaminant. Extremely persistent plastic can enter the food chain of animals through the aquatic ...environment, affect metabolic pathways and cause damage to the digestive system. But the molecular mechanism of its toxic effects on the duodenum in birds has not been elucidated. To investigate the toxicity of phthalates in the duodenum, quails were gavaged with 250, 500, and 750 mg/kg doses of DEHP for 45 days, and water and oil control groups were retained. This study revealed that subchronic exposure to DEHP could lead to duodenal barrier defect in quail. The damage to duodenum was reflected in a reduction in V/C and tight junction proteins. Moreover, DEHP also led to a breakdown of antimicrobial defenses through the flora derangement, which acted as a biological barrier. The massive presence of Lipopolysaccharide (LPS) led to the activation of TLR4 receptors. In addition, DEHP activated oxidative stress, which synergized the inflammatory response induced by the TLR4-NFκB pathway, and further promoted duodenum damage. This study provides a base for the further effect of phthalates on the microbiota-barrier-immune interaction.
DEHP (a commonly used phthalate) induced duodenal barrier defect and flora derangement of quail, which is sensitive to environmental pollutants. This study provides a base for the further effect of phthalates on the microbiota-barrier-immune interaction. Display omitted
•Duodenal barrier defect disrupts microbiota-barrier-immune interaction.•DEHP causes duodenal flora derangement and dysbiosis of antimicrobial function.•Duodenal Proteobacteria increased most significantly after DEHP treatment.•DEHP induces duodenum damage and decreases V/C in quail.•DEHP activates duodenal oxidative stress and inflammation in quail.
DEHP (a commonly used phthalate) is ubiquitous in the environment due to overuse. This study could warn of the health risks to animals exposed to phthalates and even humans.
Most of the current research on the photocatalytic mechanism of semiconductors is still on the simulation and evaluation of ground‐state active sites. Insights into photogenerated electron transition ...paths and excited‐state active sites during photocatalysis are still insufficient. Herein, combining femtosecond time‐resolved transient absorption spectroscopy, in situ Fourier‐transform infrared spectroscopy, synchronous illumination X‐ray photoelectron spectroscopy, and theoretical calculation results rationally reveal that in complex bimetallic oxyhalides the ultrathin rich oxygen vacancies (ROV) PbBiO2Cl (PBOC) double unit cell (DUC) layers facilitate migration and separation of photogenerated electrons from the bulk to Bi sites near the surface oxygen vacancies (OVs), then form the excited electron‐rich Bi(3–x)+ sites like quantum well structure. The excited Bi(3–x)+ sites act as wells for photogenerated electrons leading to lower energy barrier in the rate determining step for the formation of *CO from *COOH intermediate. Without photosensitizers and sacrificial agents, ROV DUC PBOC exhibit high CO generation rate (16.02 µmol h–1 g–1) that is 18 times higher than that of bulk PBOC. In situ characterization combined with theoretical calculation provides effective insight into the photocatalytic mechanism of photoexcited semiconductor materials.
In the photoexcited state, the Bi atoms near the oxygen vacancies constitute quantum‐well‐like sites and photo‐generated electrons accumulate to form Bi(3–x)+ sites, which boost separation of photo‐generated electrons and decrease the energy barrier in the rate determining step from *COOH to *CO. Thus, the rich oxygen vacancies PbBiO2Cl double unit cell layers exhibit enhanced photocatalytic CO2 to CO conversion performance.
Estimating 6D poses of objects from images is an important problem in various applications such as robot manipulation and virtual reality. While direct regression of images to object poses has ...limited accuracy, matching rendered images of an object against the input image can produce accurate results. In this work, we propose a novel deep neural network for 6D pose matching named DeepIM. Given an initial pose estimation, our network is able to iteratively refine the pose by matching the rendered image against the observed image. The network is trained to predict a relative pose transformation using a disentangled representation of 3D location and 3D orientation and an iterative training process. Experiments on two commonly used benchmarks for 6D pose estimation demonstrate that DeepIM achieves large improvements over state-of-the-art methods. We furthermore show that DeepIM is able to match previously unseen objects.
Widely used disposable plastic tableware is usually buried or directly discharged into the natural environment after using, which poses potential threats to the natural environment and human health. ...To solve this problem, nondegradable plastic tableware needs to be replaced by tableware composed of biodegradable structural materials with both food safety and the excellent mechanical and thermal properties. Here, a food‐safe sargassum cellulose nanofiber (SCNF) is extracted from common seaweed in an efficient and low energy consuming way under mild reaction conditions. Then, by assembling the SCNF into a dense bulk material, a strong sargassum cellulose nanofiber structural material (SCNSM) with high strength (283 MPa) and high thermal stability (>160 °C) can be prepared. The SCNSM also possesses good machinability, which can be processed into tableware with different shapes, e.g., knives and forks. The overall performance of the SCNSM‐based tableware is better than commercial plastic, wood‐based, and poly(lactic acid) tableware, which shows great application potential in the tableware field.
A food‐safe sargassum cellulose nanofiber (SCNF) is extracted through an efficient and low energy consuming way. Then, by assembling the SCNF into a dense bulk material, a strong structural material can be prepared. It possesses good machinability, which can be processed into tableware with better overall performance than that of commercial tableware, showing great application potential in the tableware field.
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