Lead halide perovskite (PVK) has been deemed as a promising photocatalyst alternative because of its remarkable photoelectrical properties; however, the severe charge recombination has limited its ...catalytic activity. Herein, we report a PVK-based Z-scheme heterojunction, α-Fe2O3/Amine-RGO/CsPbBr3, for high-efficiency CO2 reduction in the presence of H2O. By delicately controlling the interfacial interaction, effective Z-scheme electron transfer from α-Fe2O3 to CsPbBr3 is built, leading to boosted charge separation and prolonged carrier lifetime, as confirmed by electron spin resonance (ESR), transient absorption (TA) spectra, etc. The impactful spatial separation of photo-generated carriers in Z-scheme system finally enables an 8.3-fold enhancement in photocatalytic performance as compared to CsPbBr3. A stable product yield of 469.16 μmol g−1 and an electron consumption yield of 3,132.46 μmol g−1 are achieved. This work is expected to provide deep insights into boosting the photocatalytic performance of PVK by modulating the charge carrier dynamics.
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•All-solid-state Z-scheme α-Fe2O3/Amine-RGO/CsPbBr3 photocatalyst is designed•Boosted charge separation is achieved by controlling the interfacial interaction•Visible-light-driven overall conversion of CO2 and H2O to CH4 and O2 is achieved•The charge-carrier dynamics of Z-scheme heterojunction are investigated in detail
Although lead halide perovskite (PVK) has been deemed as a promising photocatalyst alternative because of its remarkable photoelectrical properties, the severe charge recombination has limited its catalytic activity. To solve this problem, previous scientific efforts have been widely laid on the fabrication of PVK-based type II heterojunctions or Schottky-junctions. Unfortunately, this was at the cost of the weakened reduction ability of the photo-generated electrons due to the electron transfer. Herein, a PVK-based Z-scheme photocatalyst is delicately designed to not only boost the charge separation but also preserve the high redox potential of semiconductors. By delicately controlling the interfacial interaction, effective Z-scheme electron transfer is built, which enables the largely enhanced visible-light-driven overall conversion of CO2 and H2O to CH4 and O2. This work is expected to provide a new way to rational design-effective PVK-based photocatalyst.
A halide perovskite-based Z-scheme photocatalyst is fabricated by anchoring CsPbBr3 nanocrystals on a core/shell nanorod array of amine-functionalized reduced graphene oxide-coated α-Fe2O3. Thanks to the timely and spatially separated photo-generated electrons and holes with high redox ability, it demonstrates largely enhanced photocatalytic conversion of CO2 and H2O to CH4 and O2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
ABSTRACT
Secondary components of W UMa-type contact binaries (CBs) have many special properties, two of them are excess in radius and luminosity. In order to make these specialties clear, we propose ...radial density distribution to roughly detect the interior structure of the secondaries in CBs. By comparing the radial density distribution between secondary components of CBs and main-sequence stars, we find the radial density distribution of secondaries in A-subtype CBs are similar to main-sequence stars whose masses higher than 1.8 Msun, which suggests that these two kinds of stars may have some evolutionary relationship. While secondary components of W-subtype CBs are closely connected with stars whose masses lower than 1.8 Msun. Then, we investigate the mass–luminosity relation of secondaries in CBs, the big differences between two subtypes suggests that the overluminosity of secondaries in these two subtypes are caused by two different reasons. Overluminosity in A-subtype is because the secondary components are evolved from initial more massive stars, while in W-subtype is due to energy transfer.
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•BPC CE was constructed with a B-doped carbon layer onto the P-doped carbon.•BPC CE was developed as efficient hole extractor for HTM-free perovskite solar cell.•B and P co-doping ...tuned the work function and electrical conductivity of carbon CE.•The TiO2/CH3NH3PbI3/BPC solar cell delivered a power conversion efficiency of 6.78%.
Chemical doping is adopted to tune the work function and electrical conductivity of carbon counter electrode (CE) in HTM-free organometallic halide perovskite solar cells (PSCs). In this work, the boron and phosphorus co-doped carbon (BPC) CE is constructed by coating a B doped carbon layer onto the P-doped carbon (PC). The work function of BPC CE with B/P co-doping (B: 2.68at.%, P: 2.23at.%) is thus regulated to 5.12eV from the 5.01eV of pure carbon and 4.81eV of PC, and the sheet resistance is modulated to 8.41Ωsq−1 from 14.75Ωsq−1 of pure carbon and 7.89Ωsq−1 of PC. As a consequence, the BPC-based PSCs deliver a power conversion efficiency of 6.78%, higher than those of pristine carbon (3.72%), PC (5.39%) and BC (5.20%) based PSCs, and even comparable to that of conventional Au-based device (7.22%), due to the enhanced hole extraction ability and the maintained high electronic conductivity. Moreover, the good stability in ambient condition over a period of 720h is also demonstrated in the BPC-based PSCs. The successful application of BPC CE in PSCs shows a promising way for fabricating low-cost, large-scale and highly efficient PSCs in future.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The rational synthesis of iron–sulfur clusters with excellent control of the core ligands has been a significant challenge in biomimetic chemistry. In this work, the rational construction of ...versatile Mo–Fe–S cubane clusters was realized using a LEGO strategy. (LEGO is a line of plastic construction toys consisting of various interlocking plastic bricks which can be assembled and connected in different ways to construct versatile objects. Herein we use "LEGO strategy" as an analogy for the stepwise synthetic methodology, and we use "brick" to represent a corner atom of the cubane structure.) Through careful synthetic control, the ⟨Fe⟩, ⟨S⟩, and ⟨Cl⟩ bricks were mounted piece-by-piece onto the basic ⟨MoS3⟩ frame to stepwise construct the incomplete cubane core ⟨MoFe2S3Cl⟩ and the complete cubane core ⟨MoFe3S3Cl⟩. The significantly elongated Fe–Cl bonds for the bridging chlorides in the ⟨MoFe2S3Cl⟩ and ⟨MoFe3S3Cl⟩ cores permit ligand metatheses to introduce 2p donors at the bridging sites, which used to be a challenge in traditional iron–sulfur chemistry. Therefore, in subsequent controlled reactions, the bridging ⟨Cl⟩ bricks of the ⟨MoFe2S3Cl⟩ and ⟨MoFe3S3Cl⟩ frames could be easily replaced by ⟨N⟩ , ⟨O⟩, or ⟨S⟩ bricks to generate the ⟨MoFe2S3N⟩, ⟨MoFe2S3O⟩, ⟨MoFe3S3N⟩, and ⟨MoFe3S4⟩ cluster cores, demonstrating more choices for the LEGO synthetic strategy. The series of Mo–Fe–S clusters and their derivatives, together with related synthetic strategies, offers a good platform and methodology for biomimetic chemistry in relation to nitrogenase, especially the FeMo cofactor.
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IJS, KILJ, NUK, PNG, UL, UM
The biological safety of mesoporous silica nanoparticles (MSNs) has gradually attracted attention. However, few studies of their toxicity to the intestine and mechanism are available. In this study, ...their primary structures were characterized, and their subacute toxicity to mice was investigated. After 2 weeks of intragastric administration of MSNs, they significantly enhanced serum ALP, ALT, AST and TNF-α levels and caused infiltration of inflammatory cells in the spleen and intestines. MSNs induced intestinal oxidative stress and colonic epithelial cell apoptosis in mice. Intestinal epithelial cells exhibited mitochondrial ridge rupture and membrane potential decrease after MSN treatment. Additionally, MSNs increased ROS and NLRP3 levels and inhibited expression of the autophagy proteins LC3-II and Beclin1. MSNs significantly changed the intestinal flora diversity in mice, especially for harmful bacteria, leading to intestinal microecology imbalance. Meanwhile, MSNs influenced the expression of metabolites, which were involved in a range of metabolic pathways, including pyrimidine metabolism, central carbon metabolism in cancer, protein digestion and absorption, mineral absorption, ABC transport and purine metabolism. These results indicated that the subacute toxicity of mesoporous silicon was mainly caused by intestinal damage. Thus, our research provides additional evidence about the safe dosage of MSNs in the clinical and food industries.
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•MSNs caused intestinal inflammatory damage.•MSNs led to mitochondrial damage and autophagy inhibition.•MSNs induced disorder of microecology.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
AIM To optimize the efficacy of noninvasive evaluations in monitoring the endoscopic activity of inflammatory bowel disease(IBD).METHODS Fecal calprotectin(FC), clinical activity index(CDAI or CAI), ...C-reactive protein(CRP), erythrocyte sedimentation rate(ESR), and procalcitonin(PCT) were measured for 136 IBD patients. Also, FC was measured in 25 irritable bowel syndrome(IBS) patients that served as controls. Then, endoscopic activity was determined by other two endoscopists for colonic or ileo-colonic Crohn’s disease(CICD) with the “simple endoscopic score for Crohn’s disease”(SES-CD), CDrelated surgery patients with the Rutgeerts score, and ulcerative colitis(UC) with the Mayo score. The efficacies of these evaluations to predict the endoscopic disease activity were assessed by Mann-Whitney test, χ~2 test, Spearman’s correlation, and multiple linear regression analysis.RESULTS The median FC levels in CD, UC, and IBS patients were 449.6(IQR, 137.9-1344.8), 497.9(IQR, 131.7-118.0), and 9.9(IQR, 0-49.7) μg/g, respectively(P < 0.001). For FC, CDAI or CAI, CRP, and ESR differed significantly between endoscopic active and remission in CICD and UC patients, but not in CD-related surgery patients. The SES-CD correlated closely with levels of FC(r = 0.802), followed by CDAI(r = 0.734), CRP(r = 0.658), and ESR(r = 0.557). The Mayo score also correlated significantly with FC(r = 0.837), CAI(r = 0.776), ESR(r = 0.644), and CRP(r = 0.634). For FC, a cut-off value of 250 μg/g indicated endoscopic active inflammation with accuracies of 87.5%, 60%, and 91.1%, respectively, for CICD, CD-related surgery, and UC patients. Moreover, clinical FC activity(CFA) calculated as 0.8 × FC + 4.6 × CDAI showed higher area under the curve(AUC) of 0.962 for CICD and CFA calculated as 0.2 × FC + 50 × CAI showed higher AUC(0.980) for UC patients than the FC. Also, the diagnostic accuracy of FC in identifying patients with mucosal inflammation in clinical remission was reflected by an AUC of 0.91 for CICD and 0.96 for UC patients. CONCLUSION FC is the most promising noninvasive evaluation for monitoring the endoscopic activity of CICD and UC. CFA might be more accurate for IBD activity evaluation.
Stimuli‐responsive nanoporous materials represent a newly emerging category of functional materials, for which instant and significant response behavior is strongly demanded but still challenging. ...Herein, a new kind of conjugated poly(ionic liquid)s (PILs) synthesized via a simple one‐pot spontaneous nucleophilic substitution and polymerization between 4,4'‐vinylenedipyridine and propargyl bromide is reported. A nanoporous membrane actuator is further developed via ionic complexation between the current PIL and trimesic acid. The actuator carries a gradient density in the hydrophobicity content along the membrane cross‐section, which results in a fast response to moisture.
Conjugated poly(ionic liquid)s with a polyacetylene backbone is synthesized simply by mixing 4,4'‐vinylenedipyridine and propargyl bromide under mild conditions. The as‐prepared polymer A‐TFSI exhibits reversible solid‐to‐gel conversion with an increase in temperature. Furthermore, the A‐TFSI‐based nanoporous membrane exhibits a fast response to moisture and large‐scale displacement, which shows great capability for biomimetic movements and interfacing with biological environments.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A DEM model incorporating realistic sand shape was developed to simulate sand-clay mixture (SCM) behaviour based on CT images acquired during uniaxial compression of a SCM containing quartz sand ...(SCM_R) and a SCM containing glass beads (SCM_S) with in-situ X-ray micro-tomography scanning. The influences of shape, size and content of sand grains on the uniaxial behaviour of SCM were studied. SCM_R revealed a higher peak strength and elastic modulus than SCM_S with the same sand content, sand size and initial void ratio. Increasing sand content led to significantly reduced peak strength for both SCM, and remarkably increased and unnoticeably changed elastic modulus for SCM_R and SCM_S, respectively. Meanwhile, increasing sand size resulted in dramatically decreased yet insignificantly varied peak strength and elastic modulus for SCM_R and SCM_S, respectively. The different phenomenon between SCM_R and SCM_S were attributed to the significantly different sand-clay bond intensities and interface interlocking effects between them.
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•CT image-based DEM model incorporating realistic sand shape of sand-clay mixtures.•Sand-clay mixtures (SCM) uniaxially compressed with in-situ X-ray μCT scanning.•DEM model calibration with both macro- and micro-mechanical experimental data.•Lower peak strength and elastic modulus of SCM with spherical sand grains (SCM_S).•Different effects of sand content and size between SCM with irregular sand and SCM_S
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Herein we demonstrate how the combined use of the molecular building block (MBB) approach and reticular chemistry allows the fabrication of a highly stable, ultra-microporous metal-organic framework ...(MOF) that is an efficient sorbent for the challenging separation of propane/propylene.
A silver-catalyzed glycosylation reaction employing readily accessible and stable glycosyl ynenoates is developed. This reaction is mostly high yielding and exhibits varying levels of stereoinversion ...at the anomeric position. Compared to established and versatile Yu's gold catalysis, this chemistry features the use of substantially cheaper AgNTf
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