Fabrication of ZnO Scaffolded CdS Nanostructured Photoanodes with Enhanced Photoelectrochemical Water Splitting Activity under Visible Light.

CdS, characterized by its comparatively narrow energy band gap (∼2.4 eV), is an appropriate material for prospective use as a photoanode in photoelectrochemical water splitting. Regrettably, it encounters several obstacles for practical and large-scale applications, including issues such as bulk carrier recombination and diminished conductivity. Here, we have tried to address these challenges by fabricating a novel photoelectrode (ZnO/CdS) composed of one-dimensional ZnO nanorods (NRs) decorated with two-dimensional CdS nanosheets (NSs). A facile two-step chemical method comprising electrodeposition along with chemical bath deposition is employed to synthesize the ZnO NRs, CdS NSs, and ZnO/CdS nanostructures. The prepared nanostructures have been investigated by UV-visible absorption spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy. The fabricated ZnO/CdS nanostructures have shown enhanced photoelectrochemical properties due to the improvement of the semiconductor junction surface area and thereby enhanced visible light absorption. The incorporation of CdS NSs has been further found to promote the rate of the charge separation and transfer process. Subsequently, the fabricated ZnO/CdS photoelectrodes achieved a photocurrent conversion efficiency 3 times higher than that of a planar ZnO NR photoanode and showed excellent performance under visible light irradiation. The highest applied bias photon-to-current conversion efficiency (% ABPE) of about ∼0.63% has been obtained for the sample with thicker CdS NSs on ZnO NRs with a photocurrent density of ∼1.87 mA/cm2 under AM 1.5 G illumination. The newly synthesized nanostructures further demonstrate that the full photovoltaic capacity of nanomaterials is yet to be exhausted.

Improved photocatalytic activity of TiO2 nanoparticles through nitrogen and phosphorus co-doped carbon quantum dots: an experimental and theoretical study.

In this work, we develop a photocatalyst wherein nitrogen and phosphorus co-doped carbon quantum dots are scaffolded onto TiO2 nanoparticles (NPCQD/TiO2), denoted as NPCT hereafter. The developed NPCT photocatalyst exhibits an enhanced visible light photocatalytic hydrogen production of 533 µmol h-1 g-1 compared to nitrogen doped CQD/TiO2 (478 µmol h-1 g-1), phosphorus doped CQD/TiO2 (451 µmol h-1 g-1) and pure CQD/TiO2 (427 µmol h-1 g-1) photocatalysts. The enhanced photocatalytic activity of the NPCT photocatalyst is attributed to the excellent synergy between NPCQDs and TiO2 nanoparticles, which results in the creation of virtual energy levels, a decrease in work function and suppressed recombination rates, thereby increasing the lifetime of photogenerated electrons. A detailed mechanism is proposed for the enhancement in visible light hydrogen production by the NPCT photocatalyst from the experimental results, Mott-Schottky plots and ultraviolet photoelectron spectroscopy results. Further, first-principles density functional theory (DFT) simulations are carried out which predict the decrease in the work function and band gap, and the increase in the density of states of NPCT as the factors responsible for the observed enhancement in visible light photocatalytic hydrogen production.

Exploring the emerging applications of the advanced 2-dimensional material borophene with its unique properties.

Borophene, a crystalline allotrope of monolayer boron, with a combination of triangular lattice and hexagonal holes, has stimulated wide interest in 2-dimensional materials and their applications. Although their properties are theoretically confirmed, they are yet to be explored and confirmed experimentally. In this review article, we present advancements in research on borophene, its synthesis, and unique properties, including its advantages for various applications with theoretical predictions. The uniqueness of borophene over graphene and other 2-dimensional (2D) materials is also highlighted along with their various structural stabilities. The strategy for its theoretical simulations, leading to the experimental synthesis, could also be helpful for the exploration of many newer 2D materials.

Prediction model for successful radiocephalic arteriovenous fistula creation in patients with diabetic nephropathy.

Arteriovenous fistula (AVF) is the most appropriate vascular access for all chronic kidney disease patients for hemodialysis. However, patients with diabetic nephropathy are at increased risk for primary failure after AVF creation, mainly due to atherosclerosis and calcification of blood vessels. We conducted this study to find out the risk factors for primary failure of radiocephalic AVF in end-stage renal disease (ESRD) patients due to diabetic nephropathy and develop a risk predicting model. This study was conducted at a tertiary care teaching hospital of South India. Patients with ESRD due to diabetic nephropathy whom underwent left radiocephalic AVF at wrist were enrolled. Risk factors for primary failure were analyzed by univariate and multivariate logistic regression models. Sixty-six patients were included in the study. Thirty-one patients had a primary failure. Independent risk factors for primary failure were palpable vessel wall of the radial artery (P = 0.003, odds ratio [OR] = 15.317), smaller radial artery diameter (P = 0.001, OR = 16.526), radial artery peak systolic velocity (PSV) <45 cm/s (P = 0.005, OR = 8.494), and linear radial artery calcification (P = 0.006, OR = 7.942). The risk predicting model obtained by adding the score given for each risk factors (vessel wall not palpable = 0, palpable = 1, no linear calcification in digital X-ray = 0, linear calcification = 1, PSV ≥45 cm/s = 0, <45 cm/s = 1 and 2.5 - radial artery diameter in mm) had an area under receiver-operating characteristic curve of 0.886. Cutoff score of 1.5 had sensitivity of 83.9% and specificity of 80.0% for primary failure. Risk predicting model for primary failure based on condition of the vessel wall on palpation, radial artery diameter, flow velocity, and calcification may be helpful for suitable patient selection.