Non‐noble metal‐based bifunctional electrocatalysts are highly desired for water electrolysis. However, constructing a water electrolyzer using a sole catalyst without compromising either its oxygen ...evolution reaction (OER) or hydrogen evolution reaction (HER) performance is still challenging. In this study, a simple strategy is developed to integrate 2 D and 0 D CoP in the same metal–organic framework precursor‐derived hollow N‐doped carbon nanotube‐assembled polyhedron (HNCNP). The unique hierarchical structure endows the resulting nanocomposite with both the advantages of more exposed active sites for 2 D and large surface‐to‐volume ratio for 0 D materials, whereas the hollow interior could benefit the charge and mass transfer properties. Thus, CoP/HNCNP@2 D CoP exhibits outstanding OER and HER activity and a low cell voltage when employed as both the anode and cathode in a two‐electrode water electrolyzer. The approach of integrating the same metal phosphide phase with diverse dimensions may inspire new ways to design hierarchical nanostructures for advanced energy conversion applications.
Combining dimensions: Simple integration of 2 D nanosheets and 0 D nanoparticles of CoP in the same pristine ZIF‐derived hollow N‐doped carbon nanotube‐assembled polyhedron (HNCNP) is reported. The well‐interconnected 3 D architecture of CoP/HNCNP@2 D CoP exhibits remarkable activity and stability for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in overall water splitting in alkaline solution.
•Intercropped proso millet had greater competitive ability than mung bean.•Roots of species were promoted by intercropping and expanded to the middle spaces.•Changes in root structure were conducive ...to the absorption of soil water.•Optimum combination was 2 rows of proso millet intercropped with 4 rows of mung bean.
Proso millet (Panicum miliaceum L.)/mung bean (Vigna radiata L.) intercropping could serve as a new cereal/legume planting pattern to increase crop production. However, how these two crop species compete for resources by stimulating root development and water uptake is unknown. An experiment was conducted at the Northwest A&F University experimental site in northwestern China from 2017 to 2019 to investigate the mechanisms governing the yield responses of both crops and compare interspecific interactions by analyzing the root distribution and water-use efficiency (WUE) of the crops. Intercropped proso millet dominated, as indicated by the highly positive aggressivity (Apm; averaging 1.66) and relative crowding coefficient (Kpm; averaging 2.66). The root growth and distribution of both crops increased under intercropping, with lateral expansion to the middle interrow spaces during the cogrowth period, resulting in greater root length density, surface area density, and volume density in the upper layer (0−50 cm) and close to the plants. This allowed the absorption of more soil water, which helped increase the WUE of intercropped proso millet. These improvements occurred due to significant correlations between soil water content and root structure. However, the relatively short mung bean was shaded by the taller proso millet, creating a disadvantage reflected by the decreased plant biomass and WUE of the former. Compared with grain yield under monocultures, the grain yield of the intercropped proso millet and mung bean increased by 13.9–50.0 % and decreased by 31.9–47.0 %, respectively. Two rows of proso millet intercropped with four rows of mung bean (2P4M) is recommended, as this system, although reducing mung bean yields, increases proso millet yields and enables the greatest land-use efficiency in arid regions of Northwest China.
Semiconducting quantum dots (QDs) engineering is considered as an effective approach to improve the light-harvesting ability of the devices for solar energy converting. Current routes for the ...construction of QDs from metal–organic frameworks (MOFs) always retain carbon materials to avoid particle aggregations, which could obstruct light harvesting process. Herein, novel ZnCdS QDs without carbon supporting are rationally designed and fabricated by controlled annealing and a sequential sulfidation and ion-exchange procedure by a zeolitic-imidazolate-framework-8 (ZIF-8)-templated method. Notably, the quantum size could be well controlled, and hence provide the ZnCdS QDs material with suitable band matching, strong electron coupling, uniform and abundant active sites, facilitated photoinduced charge kinetics, and shortened charge diffusion distances, which are vital merits for enhancing photocatalytic performance. The photocatalytic H2 production activity of these QDs can be optimized through adjusting the quantum sizes. Under the irradiation of visible-light and noble-metal cocatalyst-free, an optimal H2 production rate of 3.70 mmol h–1 g–1 could be afford without using noble metal cocatalysts, which is superior to those of bulk ZnCdS and most of the reported ZnCdS-based catalysts. The facile and efficient approach for ZnCdS QDs engineering could be extended to design other kinds of highly efficient metal-sulfide QDs in advanced applications.
•Broomcorn millet consistently dominated the intercropped systems.•Nitrogen fertilizer application intensified the differences in growth and competition between the species.•Intercropping and N ...fertilization affected soil nutrient availability and soil microbial activity.•High N fertilizer application rates decreased the intercropping advantages.
Positive interactions in cereal/legume intercropping may drive high system productivity and ensure the sustainable development of modern agricultural practices. In this study, the effect of nitrogen (N) fertilizer application rates on soil ecoenzymatic stoichiometry, microbial nutrient status and interspecific competition during the cogrowth stages in broomcorn millet (Panicum miliaceum L.)/mung bean (Vigna radiata L.) intercropping were investigated. Two-year field experiments (2018 and 2019) involved the use of the following N treatments: N0, 0 kg N ha−1 (control); N1, 45 and 60 kg N ha−1; N2, 90 and 120 kg N ha−1; and N3, 135 and 180 kg N ha−1 for mung bean and broomcorn millet, respectively. Intercropped broomcorn millet was the dominant species determined by positive competitive ratios and aggressivity values at the early (1.70 and 1.81), middle (2.06 and 1.98), and the later cogrowth stages (3.02 and 2.48), respectively. Nitrogen application increased the competitive ratio and aggressivity by 29.4 % and 24.5 %, respectively, compared with the control. Leaf photosynthesis and aboveground biomass of the two crops were altered by the N treatment, with high N fertilizer inputs significantly reducing the intercropping advantages and land use efficiency. Intercropping and N fertilizer improved interspecific competition and boosted grain yield in 2018 and 2019, and values were 6331.8 kg ha−1 and 6531.3 kg ha−1 for broomcorn millet and 905.0 kg ha−1 and 979.8 kg ha−1 for mung bean, respectively. Moreover, intercropping and N fertilization markedly affected the soil nutrient content, microbial biomass, and enzyme activity involved in carbon (C), nitrogen (N), and phosphorus (P) acquisition in both species. The soil ecoenzymatic C:N:P acquisition ratios were strongly associated with nutrient acquisition by microbes in the rhizosphere, highlighting the importance of microbial metabolic changes driven by nutrient stoichiometry to meet the soil nutrient demands. This study provides an explanation for considering more sustainable agricultural practices of cereal/legume intercropping based on reduced fertilizer application compared with monocropping.
Non‐noble metal‐based bifunctional electrocatalysts are highly desired for water electrolysis. However, constructing a water electrolyzer using a sole catalyst without compromising either its oxygen ...evolution reaction (OER) or hydrogen evolution reaction (HER) performance is still challenging. In this study, a simple strategy is developed to integrate 2 D and 0 D CoP in the same metal–organic framework precursor‐derived hollow N‐doped carbon nanotube‐assembled polyhedron (HNCNP). The unique hierarchical structure endows the resulting nanocomposite with both the advantages of more exposed active sites for 2 D and large surface‐to‐volume ratio for 0 D materials, whereas the hollow interior could benefit the charge and mass transfer properties. Thus, CoP/HNCNP@2 D CoP exhibits outstanding OER and HER activity and a low cell voltage when employed as both the anode and cathode in a two‐electrode water electrolyzer. The approach of integrating the same metal phosphide phase with diverse dimensions may inspire new ways to design hierarchical nanostructures for advanced energy conversion applications.
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•Intercropping combined with N fertilization enhanced the leaf photosynthetic efficiency of proso millet.•The capture and use efficiency of various resources were increased by ...intercropping combined with N fertilization.•Intercropping combined with moderate N input increased proso millet productivity while reducing chemical fertilizer use.
Field experiment was performed on the Loess Plateau of China in 2018 and 2019 to investigate the effects of intercropping with nitrogen (N) management on proso millet growth and resource utilization. A split-plot experimental design for the planting pattern (sole proso millet (SP) and proso millet/mung bean intercropping (PM)) and N fertilizer application rate (N0, 0 kg N ha−1; N60, 60 kg N ha−1; N120, 120 kg N ha−1; and N180, 180 kg N ha−1 for proso millet) was used. Results showed that intercropping combined with N fertilization enhanced the leaf photosynthetic efficiency of proso millet by facilitating stomatal opening, and such improvements were conducive to increasing the maximal quantum yield of PSII photochemistry and the photochemical quenching coefficient. Specifically, intercropping combined with the N120 treatment was an efficient farming practice that increased radiation use efficiency by 18.1 % and 17.9 %, water use efficiency by 60.2 % and 61.8 %, and N uptake by 96.0 % and 71.6 % in 2018 and 2019, respectively, compared with those parameters in the N0 treatment in the sole planting system. Similar improvements were observed for grain yield, which reached maximum values at N120 (6331.8 kg ha−1 and 6531.3 kg ha−1 in 2018 and 2019, respectively) in the PM treatment. These responses resulted in an increased harvest index and land equivalent ratio. Consequently, intercropping combined with moderate N inputs reduces the chemical fertilizer application rate and increases crop productivity and is considered to be a reasonable strategy for field management.
Affording two semiconductors with one template in one step to construct a composite with delicate structures may endow low-cost photocatalysts with desired characteristics,
i.e.
, high activity, ...stability and recyclability. Herein, novel sandwich-shelled ZnCdS/ZnO/ZnCdS cages are fabricated with "one stone"-zeolitic-imidazolate-framework-8. ZnS and ZnO are formed simultaneously in the sulfidation stage, where ZnS serves as a barrier to localize the ZnO particles filling up the voids between the ZnS layers. It could therefore be very advantageous in photocatalysis that the ZnCdS, derived from cation-exchanged ZnS, and ZnO with well-defined interfaces also have staggered band structure configurations by virtue of the fine adjustment of the composition. The Zn
0.5
Cd
0.5
S/ZnO/Zn
0.5
Cd
0.5
S cages exhibit a H
2
production rate of 28.6 mmol g
−1
h
−1
and long-term durability, achieving the highest activities among the ZnCdS and ZnO families under noble-metal-free conditions. This remarkable performance could be ascribed to the unique morphology of the sandwich-shell and hollow interior integrating multiple vital merits for photocatalysis, including the enhanced light-harvesting ability, abundant active sites, shortened charge diffusion distances, and Z-scheme mechanism featuring preserved strong redox ability and improved charge separation and migration. This facile strategy may offer great opportunities in developing highly active metal sulfide/oxide-based photocatalysts for practical applications.
Novel sandwich-shelled ZnCdS/ZnO/ZnCdS dodecahedral cages are synthesized with "one stone", exhibiting advanced performance towards photocatalytic hydrogen production.
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•Improvement of flesh quality/flavor of crucian carp fish muscle by STMFPS treatment.•Purine, pyrimidine and glycerophospholipid metabolism were regulated under STMFPS ...treatment.•STMFPS treatment affected the ornithine cycle metabolic pathways in freshwater fish.
The short term micro-flowing purification system (STMFPS) has been shown to improve the flesh quality of freshwater fish. However, few studies have focused on the involved underlying mechanisms. This study explored the effect of STMFPS on the flesh quality of market-size freshwater fish based on the combination of metabolomics and transcriptomics methods. The UPLC-QTOF/MS based metabolomics method was utilized to screen metabolites and predict the possible major metabolic pathways during different STMFPS treatment periods (0 d, 1 d, 5 d and 9 d). Furthermore, the transcriptomic data demonstrated that the differentially expressed genes detected in crucian carp muscle were 2915, 7852 and 7183 after 1 d, 5 d and 9 d STMFPS treatment. Results showed that the TCA cycle, ornithine cycle, purine metabolism and amino acid catabolism play important roles in improving the flesh quality of crucian carp. This study may help to understand the mechanism of improving the flesh quality of aquatic products using STMFPS.
Post-synthesis modification (PSM) is an efficient means to introduce functional chemical groups into metal-organic frameworks (MOFs) by modifying metal clusters or ligands after MOFs have been ...synthesized. Various functional chemical groups are capable of being incorporated into the frameworks by PSM without changing the original MOF structures. Herein, firstly, the synthesis mechanisms of post-synthesis modified MOFs are introduced. Secondly, their characteristics such as crystallinity, porosity, morphology, stability, and fluorescent properties are discussed. Thirdly, applications of the modified MOFs are summarized focusing on catalysts, sensors, absorbents, energy storage, and separation. Lastly, potential challenges and new visions for developing PSMs are proposed based on recent literature and our knowledge. We hope that this review can serve as a very small stepping stone in the field of MOF PSM.
Post-synthesis modification (PSM) is an efficient means to introduce functional chemical groups into metal-organic frameworks (MOFs) by modifying metal clusters or ligands after MOFs have been synthesized.
