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1.
Nanoscale ; 14(33): 12090-12098, 2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-35950504

RESUMO

An effective electron transport layer (ETL) plays a pivotal role in suppressing nonradiative recombination at the interface as well as promoting perovskite crystallization to facilitate electron extraction in perovskite solar cells (PSCs). Herein, a functional polymer, poly(amidoamine) (PM) dendrimer, is introduced to rationalize the morphology and electrical performance of SnO2 nanocrystals to construct an SnO2 charge transfer layer. PM offers an even SnO2 colloidal dispersion with a particle-size distribution of ∼10 nm, which prevents the agglomeration of nanocrystals significantly. The polymer-complexed SnO2 provides a uniform and dense ETL film without island-like agglomeration, yielding a large conductive layer superior to that of the control. Equally important, the wettability-improved SnO2 ETL with PM modification produces a high-quality perovskite film with larger grain size, resulting in a power conversion efficiency (PCE) of the champion n-i-p PSC of up to 22.93% with negligible hysteresis. Noticeably, the device based on SnO2-PM maintained 71% of its initial PCE (only 49% for the control device) after storing in the ambient environment for 45 days (relative humidity of 30%-80%) without packaging.

2.
Chemosphere ; 272: 129653, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33486455

RESUMO

The contamination of groundwater by arsenic (As) in Bangladesh is the biggest impairing of a population, with a large number of peoples affected. Specifically, groundwater of Gangetic Delta is alarmingly contaminated with arsenic. Similar, perilous circumstances exist in many other countries and consequently, there is a dire need to develop cost-effective decentralized filtration unit utilizing low-cost adsorbents for eliminating arsenic from water. Morphological synthesis of carbon with unique spherical, nanorod, and massive nanostructures were achieved by solvothermal method. Owing to their intrinsic adsorption properties and different nanostructures, these nanostructures were employed as adsorption of arsenic in aqueous solution, with the purpose to better understanding the morphological effect in adsorption. It clearly demonstrated that carbon with nanorods morphology exhibited an excellent adsorption activity of arsenite (about 82%) at pH 3, remarkably superior to the two with solid sphere and massive microstructures, because of its larger specific surface area, enhanced acid strength and improved adsorption capacity. Furthermore, we discovered that iron hydroxide radicals and energy-induced contact point formation in nanorods are the responsible for the high adsorption of As in aqueous solution. Thus, our work provides insides into the microstructure-dependent capability of different carbon for As adsorption applications.


Assuntos
Arsênio , Poluentes Químicos da Água , Purificação da Água , Adsorção , Arsênio/análise , Bangladesh , Carbono , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/análise
3.
Materials (Basel) ; 13(7)2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32290065

RESUMO

In the present study, a sequence of experiments was performed to assess the influence of the key process parameters on the formation of a carbon nanofiber-coated monolith (CNFCM), using a four-level factorial design in response surface methodology (RSM). The effect of reaction temperature, hydrocarbon flow rate, catalyst and catalyst promoter were examined using RSM to enhance the formation yield of CNFs on a monolith substrate. To calculate carbon yield, a quadratic polynomial model was modified through multiple regression analysis and the best possible reaction conditions were found as follows: a reaction temperature of 800 °C, furfuryl alcohol flow of 0.08525 mL/min, ferrocene catalyst concentration of 2.21 g. According to the characterization study, the synthesized CNFs showed a high graphitization which were uniformly distributed on a monolith substrate. Besides this, the feasibility of carbon dioxide (CO2) adsorption from the gaseous mixture (N2/CO2) under a range of experimental conditions was investigated at monolithic column. To get the most out of the CO2 capture, an as-prepared sample was post-modified using ammonia. Furthermore, a deactivation model (DM) was introduced for the purpose of studying the breakthrough curves. The CO2 adsorption onto CNFCM was experimentally examined under following operating conditions: a temperature of 30-50 °C, pressure of 1-2 bar, flow rate of 50-90 mL/min, and CO2 feed amount of 10-40 vol.%. A lower adsorption capacity and shorter breakthrough time were detected by escalating the temperature. On the other hand, the capacity for CO2 adsorption increased by raising the CO2 feed amount, feed flow rate, and operating pressure. The comparative evaluation of CO2 uptake over unmodified and modified CNFCM adsorbents confirmed that the introduced modification procedure caused a substantial improvement in CO2 adsorption.

4.
Sci Rep ; 9(1): 16358, 2019 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-31705011

RESUMO

A γ-NA5 catalyst in the form of pellet was first to be reported and was pioneering in gasification to accelerate the production of syngas through biomass (palm empty fruit brunch) conversion. The synthesised γ-NA5 pellet possesses a high surface area of 212.32 m2 g-1, which renders more active sites for hydrocarbon cracking, subsequently leading to high H2 production (0.0716 m3 kg-1). Additionally, the pellet exhibits remarkable reversibility and reusability with 91% H2 production efficiency being retained after five consecutive gasification cycles. Distinctively, the feature of the synthesised γ-NA5 pellet from the conventional powder-like catalyst is that it eases the separation of the used catalyst from the biomass ash, and subsequently facilitates regeneration solely by calcination process. The loading of 20 wt.% optimised amount of catalyst itself has successfully shorten the completion of gasification process up to 135 min, which is highly feasible for a large scale industrial usage after considering the cost of the catalyst, facile preparation method, and catalyst's effectiveness towards gasification.

5.
Sci Rep ; 8(1): 2482, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29410450

RESUMO

Perovskite solar cells based on series of inorganic cesium lead bromide and iodide mixture, CsPbBr3-xI x , where x varies between 0, 0.1, 0.2, and 0.3 molar ratio were synthesized by two step-sequential deposition at ambient condition to design the variations of wide band gap light absorbers. A device with high overall photoconversion efficiency of 3.98 % was obtained when small amount of iodide (CsPbBr2.9I0.1) was used as the perovskite and spiro-OMeTAD as the hole transport material (HTM). We investigated the origin of variation in open circuit voltage, Voc which was shown to be mainly dependent on two factors, which are the band gap of the perovskite and the work function of the HTM. An increment in Voc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Besides, the usage of bilayer P3HT/MoO3 with deeper HOMO level as HTM instead of spiro-OMeTAD, thus increased the Voc from 1.16 V to 1.3 V for CsPbBr3 solar cell, although the photocurrent is lowered due to charge extraction issues. The stability studies confirmed that the addition of small amount of iodide into the CsPbBr3 is necessarily to stabilize the cell performance over time.

6.
PLoS One ; 10(12): e0144805, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26700479

RESUMO

A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic biosurfactants without external source of CO2. The calcium carbonate crystals were rhombohedron structure and regularly shaped with side dimension ranging from 33-41 nm. The high degree of morphological control of CaCO3 nanocrystals suggested that surfactants are capable of strongly interacting with the CaCO3 surface and control the nucleation and growth direction of calcium carbonate nanocrystals. Finally, the mechanism of formation of nanocrystals in light of proposed routes was also discussed.


Assuntos
Carbonato de Cálcio/química , Nanopartículas/química , Ouriços-do-Mar/química , Tensoativos/química , Animais , Cristalização , Microscopia Eletrônica de Varredura , Difração de Raios X
7.
Nat Prod Res ; 25(10): 995-1003, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21644180

RESUMO

A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as ß-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests.


Assuntos
Artocarpus/química , Furanos/isolamento & purificação , Xantonas/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Furanos/química , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Xantonas/química
8.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 12): o3331-2, 2010 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-21589606

RESUMO

The title compound, Artonol B, C(24)H(20)O(7), isolated from the stem bark of Artocarpus kemando, consists of four six-membered rings and one five-membered ring. The tricyclic xanthone ring system is almost planar [maximum deviation 0.115 (5) Å], whereas the pyran-oid ring is in a distorted boat conformation·The furan ring is almost coplanar with the fused aromatic ring, making a dihedral angle of 3.76 (9)°. The phenol ring serves as a intra-molecular hydrogen-bond donor to the adjacent carbonyl group and also acts as an inter-molecular hydrogen-bond acceptor for the methyl groups of adjacent mol-ecules, forming a three-dimensional network in the crystal.

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