Mapping the landscape of sleep medicine training across Asia.

STUDY OBJECTIVES: This study assessed the current state of sleep medicine accreditation and training in Asia by conducting a comprehensive survey across 29 Asian countries and regions facilitated by the Asian Society of Sleep Medicine (ASSM) to identify existing gaps and provide recommendations for future enhancements. METHODS: The ASSM Education Task Force Committee designed a survey to gather data on accreditation, education, and training standards in sleep medicine, including information on challenges in enhancing education in the field. RESULTS: With an 86% (25 countries/regions) response rate, the survey showed that sleep medicine is recognized as an independent specialty in just nine countries/regions (36% of the countries/regions surveyed). Ten countries/regions have established sleep medicine training programs, with Japan and Saudi Arabia offering it as a distinct specialty. Significant disparities in training and accreditation standards were identified, with many countries/regions lacking formalized training and practice guidelines. The survey also revealed that most local sleep societies across Asia support the development of an Asian Sleep Medicine Training Curriculum led by the ASSM. However, several barriers significantly impede the establishment and development of sleep medicine training programs, including the scarcity of trained specialists and technologists and the absence of national accreditation for sleep medicine. CONCLUSIONS: The survey highlights the need for standardized sleep medicine training and accreditation across Asia. Developing an Asian Sleep Medicine Training Curriculum and promoting ASSM accreditation guidelines are key recommendations. Implementing these strategies is essential for advancing sleep medicine as a widely recognized discipline throughout Asia.

Pituitary Adenoma Prevalence and Characteristics of Omani Patients: A Single Center Experience.

Objectives: To estimate the incidence of pituitary adenomas (PA) in adult Omani patients and describe its epidemiological, clinical, and radiological characteristics. Methods: In this longitudinal, descriptive study, we reviewed the records of all PA patients from January 2015 to January 2020 who presented at the endocrinology facilities at Sultan Qaboos University Hospital, Muscat. Results: The participants comprised of 112 Omani patients with PA. The incidence of PA among all adult patients at Sultan Qaboos University Hospital (inpatient and outpatient) over five years (2015-2020) was 0.23%. The cohort had a mean age of 41.0±15.0 years. Of the 112 patients included in this study, 79 (70.5%) were women. Nearly half (51; 45.5%) of adenomas were prolactinomas while 46 (41.1%) were non-functioning adenomas, and seven (6.3%) were growth hormone-secreting adenomas while six (5.4%) were adrenocorticotropic hormone secreting adenomas. Headache was present in 67 (59.8%) patients, followed by visual field defects (40; 35.7%), galactorrhea (26; 23.2%), and fatigue (19; 17.0%). The majority of women (45/79; 57.0%) presented with menstrual cycle abnormalities. Radiological appearances were nearly equally distributed between micro- and macroadenomas. Most cases (58/112; 52.0%) of PA were treated medically by cabergoline, octreotide, and replacement therapies such as hydrocortisone and thyroxin, 38 (33.9%) were treated surgically (mainly by trans-sphenoidal pituitary resection), and the remaining 10 (8.9%) cases were subjected to radiotherapy. Medical treatment combined with surgery was employed for 15 (13.4%) patients. Conclusions: In our investigation, PA was primarily prevalent among Omani female patients, and the most common subtype of pituitary tumors was prolactinomas. The most common presentation symptom was headaches; most female patients had menstrual irregularities. Medical treatment was the primary approach for the applicable types of PAs, while surgery and radiotherapy were found to be secondary and tertiary treatment options, respectively.

Elevated oxidative stress biomarkers in adults with segmented sleep patterns.

STUDY OBJECTIVES: We investigated the association between different sleep patterns and inflammatory and oxidative stress biomarkers in adults. METHODS: A total of 321 consented adults who fulfilled the inclusion criteria were recruited in this cross-sectional study. The inclusion criteria were mainly based on apparently healthy adults aged 18-59 years. To identify sleep patterns, participants were requested to wear the actigraph for 1 week for 24 hours a day. Fasting blood was collected from each participant at day 8. The blood serum was analyzed for inflammatory and oxidative stress biomarkers. Sleep patterns were defined as monophasic (1 episode of night sleep) biphasic (2 episodes of sleep; night and aternoon siesta), and polyphasic sleep pattern (3 or more sleep episodes). RESULTS: There was no correlation between night sleep duration, total sleep in 24 hours, and napping among inflammatory and oxidative stress biomarkers: high-sensitivity C-reactive protein, malondialdehyde, total glutathione, and basal oxidizability status. Actigraphy reports showed 3 sleep patterns in this cohort, monophasic (24.3%), biphasic-napping (45.2%) and polyphasic (30.5%). Individuals with segmented sleep patterns were significantly associated with oxidative stress biomarkers. A polyphasic sleep pattern was significantly associated with higher basal oxidizability status (P = .023), whereas a biphasic sleep pattern showed higher malondialdehyde (P = .036) as compared to a monophasic sleep pattern. Total glutathione was significantly higher in monophasic sleepers (P = .046). There was no difference in serum high-sensitivity C-reactive protein among all sleep patterns. CONCLUSIONS: Segmented sleep in polyphasic and biphasic sleep patterns is associated with higher serum malondialdehyde and basal oxidizability status in particular. Further studies are recommended on the cardiometabolic impact of oxidative stress biomarkers in individuals with segmented sleep. CITATION: Al Lawati I, Zadjali F, Al-Abri MA. Elevated oxidative stress biomarkers in adults with segmented sleep patterns. J Clin Sleep Med. 2024;20(6):959-966.

Microwave-assisted synthesis of Limonia acidissima Groff gum stabilized palladium nanoparticles for colorimetric glucose sensing.

Herein, we present a novel microwave-assisted method for the synthesis of palladium nanoparticles (PdNPs) supported by Limonia acidissima Groff tree extract gum. The synthesized PdNPs were characterized using various analytical techniques, including FTIR, SEM, TEM, UV-visible, and powder XRD analyses. TEM and XRD analysis confirmed that the synthesized LAG-PdNPs are highly crystalline nature spherical shapes with an average size diameter of 7-9 nm. We employed these gum-capped PdNPs to investigate their peroxidase-like activity for colorimetric detection of hydrogen peroxide (H2O2) and glucose. The oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2, catalyzed by PdNPs, produces oxidation products quantified at 652 nm using spectrophotometry. The catalytic activity of PdNPs was optimized with respect to temperature and pH. The developed method exhibited a linear range of detection from 1 to 50 µm, with detection limits of 0.35 µm for H2O2 and 0.60 µm for glucose.

Nanomaterial grafted polymorphous activated carbon cloth surface for antibacterial, capacitive deionization and oil spill cleaning applications.

This work reports the development of multifunctional or polymorphous surfaces using zinc oxide (ZnO) nanorods, silica (SiO2), and fluoropolymer functionalization in a sequential process. Firstly, zinc oxide nanorods were grown on activated carbon cloth (ACC) using a simple low-temperature synthesis process. ZnO nanorods-coated ACC substrate was applied to investigate the antimicrobial properties, and the results showed inhibition of 50% for Escherichia coli (E.coli) and 55% for Bacillus subtilis (B.subtilis) over 48 h of incubation time. Subsequent in-situ modification of silica nanoparticles like layer on ZnO nanorods-coated ACC surface was developed and used as an electrode for brackish water desalination in a capacitive deionization system. ZnO-SiO2 modified ACC surface enhanced the desalination efficiency by 1.6 times, the salt removal rate (SRR) by threefold, and the durability (fouling prevention) for long-term usage compared to pristine ACC. Further modification of the ZnO-SiO2-ACC surface using fluoropolymer rendered the surface superhydrophobic and oleophilic. Vegetable (1.4 g/g) and crude oil (1.6 g/g) adsorption capacities were achieved for modified surface which was 70% enhancement compared with pristine ACC. The dynamic oil spill adsorption test exhibited the complete removal of oil spills on water surfaces within a few seconds, suggesting a potential application in oil spill cleaning.

Use of waste marble powder for the synthesis of novel calcium-rich biochar: Characterization and application for phosphorus recovery in continuous stirring tank reactors.

This study investigates-for the first time-the synthesis of a novel Ca-rich biochar (N-Ca-B) and its potential use for phosphorus (P) recovery from both synthetic solutions (SS) and treated urban wastewater (TUW) in a continuous stirring tank reactor (CSTR) mode. The novel biochar was synthesized by pyrolysis at 900 °C of a mixture composed of three different materials: animal biomass (poultry manure; PM), lignocellulosic waste (date palm fronds; DPFs), and abundant mineral waste (waste marble powder; WMP). Characterization of N-Ca-B showed that it has good textural properties: well-developed porosity, and high specific surface area. Furthermore, high calcium hydroxide (Ca(OH)2) and calcium oxides (CaO) nanoparticle loads were observed on the biochar surface. The dynamic CSTR assays indicated that the P recovery efficiency mainly depended on the biochar mass, P influent concentration, and, especially, the Ca content of the feeding solution. Owing to its richness in Ca cations, TUW exhibited the highest adsorbed P amount (109.2 mg g-1), i.e., about 14% larger than the SS. P recovery occurs through precipitation as hydroxyapatite, surface complexation, and electrostatic interactions with positively charged biochar particles. In real-world scenarios, CSTR systems can be applied as a tertiary treatment step in existing wastewater treatment plants (WWTPs). Decanted P-loaded biochar can be used in agriculture as a slow-release fertilizer instead of commercial products.

Towards technology, economy, energy and environment oriented simultaneous optimization of ammonia production process: Further analysis of green process.

Ammonia is one of the most produced chemicals around the world due to its various uses. However its traditional production process is associated with high fossil fuel consumption. To avoid this, the production of green ammonia can be done, and one of the considered production methods is water electrolysis, where the hydrogen needed for the manufacturing of ammonia is produced using solar energy. In this work, multi-objective optimization (MOO) is carried out for two ammonia synthesis processes with water electrolysis. One process uses solar energy to generate electricity for the whole process (Green ammonia), while the other uses natural gas for the same purpose (non-green ammonia) on a small production scale. The process is simulated using ProMax 5.0 and MOO is done using Excel-based MOO with I-MODE algorithm. Several MOO cases are solved with different objectives like CO2 emissions and energy (ENG) minimization, and Profit and Purity maximization in two and three objective cases. To conduct the work, several decision variables are selected like the operating temperatures and pressures of different streams in addition to the flow rate of nitrogen and water. Some constraints regarding the purity and reactors temperature are considered as well. The obtained results showed that the profit of green ammonia process (ranges between 0.7 and 80 M$/yr) is lower compared to the non-green process (ranges between 0.8 and 4.4 M$/yr). On the other hand, huge CO2 emissions (up to 38000 tons/yr) are produced in the non-green process compared to almost zero emissions with the green process. In most cases, water and nitrogen flow rates showed a high influence on the results and caused conflict between the objectives.

Exploring Hikikomori-like idiom of distress a year into the SARS-CoV-2 pandemic in Oman: Factorial validity of the 25-item Hikikomori Questionnaire, prevalence and associated factors.

BACKGROUND: Existing literature that examines the Hikikomori-like idiom of distress (HLID) initially labelled this phenomenon as a culture-bound syndrome. However, the increasing number of reports from other parts of the world suggest that HLID could instead be a culture-reactive idiom of distress, originating from biopsychosocial disequilibrium and cultural upheaval. The impact of imposed social withdrawal due to the Coronavirus 2 severe acute respiratory syndrome (SARS-CoV-2) pandemic on the growing prevalence of HLID has not yet been adequately explored. Aims: The first objective is to examine the factorial validity of the 25-item Hikikomori Questionnaire (HQ-25) in Oman. Second, we aimed to investigate the prevalence of HLID following the lifting of SARS-COV-2 restrictions in the Arabian Gulf country of Oman. The third related objective is to examine factors associated with the variation of HLID. METHODS: This cross-sectional online survey was widely distributed across the diverse socio-demographic population residing in Oman. After the validation of the questionnaire and the factorial validity, the Arabic version of HQ-25 was used to explore the prevalence and factors associated with HLID. RESULTS: A total of 1529 participants were included in the study (response rate = 76.5%), of whom 44% (n = 673) expressed HLID. We randomly split it into half, one for exploratory factor analysis (EFA) (n = 764) and the other half for confirmatory factor analysis (CFA) (n = 765). From the EFA results, a three-factor model was found for the Omani version of HQ-25, which represented 52.87% of the variance with good internal reliability (Overall Cronbach's: 0.92; Socialisation: 0.92; Isolation: 0.84; Emotional support: 0.73). The CFA results report acceptable goodness-of-fit indices (χ2/df = 17.92, p < .001; CFI = 0.90; TLI = 0.95; RMSEA = 0.04, 95% CI 0.02-0.07; SRMR = 0.05) of the three-factor model of the collected samples. All 1529 data were used in the respondents. The results of the logistic regression showed that married marital status (OR = 1.51, 95% CI: 1.12-2.03, p = 0.007), older age (OR = 0.97, 95% CI: 0.95-0.99, p = 0.008), living in an urban area (OR = 0.71, 95% CI: 0.56-0.91, p = 0.006), unemployed occupational status (OR = 1.72, 95% CI: 1.30-2.88, p < .001), screen time (7+ hours vs. <4 hours: OR = 4.50, 95% CI: 3.16-6.41, p < .001; 4-7 hours vs. <4 hours: OR = 2.10, 95% CI: 1.61-2.70, p < .001), history of mental illness (OR = 3.70, 95% CI: 2.29-5.91, p < .001), and adverse childhood experiences (OR = 2.60, 95% CI: 2.03-3.20, p < .001) were significant risk factors for HLID. CONCLUSION: The factorial validity of the HQ-25 performed in this study appears to mirror the previously reported 3-factor structures. Some of the associated factors appear to support and, conversely, dissent from the findings of previous studies. These are discussed in terms of the attributions of the SARS-COV-2 pandemic, demographic trends in Oman, and sociocultural factors specific to the region of interest.

Development of portable sensor for the detection of bacteria: effect of gold nanoparticle size, effective surface area, and interparticle spacing upon sensing interface.

In this study, systematic development of a portable sensor for the rapid detection of Escherichia coli (E. coli) and Exiguobacterium aurantiacum (E. aurantiacum) was reported. A conductive glass was utilized as a substrate and developed the electrode patterns on it. Trisodium citrate (TSC) and chitosan-stabilized gold nanoparticles (AuNPs) (CHI-AuNP-TSC) and chitosan-stabilized AuNPs (CHI-AuNP) were synthesized and utilized as a sensing interface. The morphology, crystallinity, optical properties, chemical structures, and surface properties of immobilized AuNPs on the sensing electrodes were investigated. The sensing performance of the fabricated sensor was evaluated by using an electrochemical method to observe the current changes in cyclic voltammetric responses. The CHI-AuNP-TSC electrode has higher sensitivity toward E. coli than CHI-AuNP with a limit of detection (LOD) of 1.07 CFU/mL. TSC in the AuNPs synthesis process played a vital role in the particle size, the interparticle spacing, the sensor's effective surface area, and the presence of CHI around AuNPs, thus enhancing the sensing performance. Moreover, post-analysis of the fabricated sensor surface exhibited the sensor stability and the interaction between bacteria and the sensor surface. The sensing results showed a promising potential for rapid detection using a portable sensor for various water and food-borne pathogenic diseases.

The Relationship Between Epilepsy Control and the Duration of Nighttime Sleep and Afternoon Siesta.

CONTEXT: The association between epilepsy control and the duration of sleep among people with epilepsy (PWE) is not well studied in Middle Eastern countries such as Oman. AIMS: To describe the sleep habits of PWE in Oman and explore the association of their sleep habits at night and afternoon siesta with the level of seizure control achieved and antiseizure medications (ASMs) consumed. METHODS: The subjects of this cross-sectional study were adult epilepsy patients attending a neurology clinic. Their sleep parameters were measured for one week using actigraphy. Home sleep apnea testing for one night was conducted to rule out obstructive sleep apnea (OSA). RESULTS: A total of 129 PWE completed the study. Their mean age was 29.8 ±â€¯9.2  years, and their mean body mass index (BMI) was 27.1 kg/m2. There was no significant difference between the people with controlled and uncontrolled epilepsy as regards the duration of night sleep or afternoon siesta (p = 0.24 and 0.37, respectively). There was also no significant correlation between their nighttime sleep duration, afternoon siesta, and the number of ASMs they consumed (p = 0.402 and 0.717, respectively). CONCLUSION: The study revealed that the sleep habits of PWE with uncontrolled epilepsy who consumed more ASMs were not significantly different from those with controlled epilepsy who consumed fewer ASMs.

Knowledge and attitude about organ donation and transplantation among Omani university students.

Background: Despite the importance of organ donation and transplantation in improving the quality of life, still, there is a shortage of organ donations, worldwide. Lack of knowledge among the public could be the reason. In previous studies, the focus was predominantly on medical students at universities. The aim of this study was to assess university students' knowledge and attitude about organ donation and transplantation among different colleges at the university. Method: A cross-sectional study was conducted among university students between August 2021 and February 2022 using a validated self-designed questionnaire. The questionnaire consisted of five sections. The first section was about the research information. The second section was informed consent. The third section was about sociodemographic information. The fourth section was about the knowledge of organ donation. The last section was about the attitude toward organ donation. The data were analyzed by descriptive statistics and chi-square tests. Results: The study included 2,125 students. 68.1% were females, and 93.1% were in the age group 17-24 years old. Only 34.1% had good knowledge about organ donation, 70.2% had a low attitude, and 7.53% had adequate information about brain death. The most common reason for supporting donating organs among university students was to save a life (76.8%) and the most common reason for refusing organs, was I am still unaware. In addition, only 25.66% of the participants had a high attitude toward people with poor knowledge about organ donation. The majority of the students (84.13%) used online sources and social networks as the primary sources of information about organ donation. Conclusion: The knowledge and attitudes of university students toward organ donation and transplantation were low. Saving a life was the most common reason for supporting organ donation, and knowledge was the biggest obstacle. Online sources and social networks were the primary sources of knowledge. The attitude was greatly influenced by knowledge. Organizing campaigns, and events, and incorporating organ donation and transplantation into university curricula will increase university students' knowledge and attitudes.

Circadian Rhythm, Sleep, and Immune Response and the Fight against COVID-19.

Sleep is an imperative physiological aspect that plays a vital role in maintaining hormonal and humeral functions of the body and hence a healthy life. Circadian rhythms are daily oscillations in human activities and physiology that prepare human beings to better react to and anticipate challenges in the surrounding environment, which are a consequence of diurnal changes of day and night. The sleep/wake cycle is one of the most prominent manifestations of the circadian rhythm and communicates tightly with the immune system with daily oscillation of immunity. Sleep deprivation is now recognized as a common condition inherent to modern society, and it is detrimental to certain body functions, particularly immune function. The aim of this review is to explore the role of sleep in maintaining a healthy immune system during the COVID-19 pandemic. The review discusses sleep-regulatory substances that are linked to host defense mechanisms such as interleukin-1ß, interleukin-6, tumor necrosis factor alpha, and interferon gamma. Cytokine levels also fluctuate with sleep/wake homeostasis and our review explores the relationship between sleep and cytokines and proposed therapeutics. The review will also cover sleep and immune response in children, adolescents, and healthcare workers, and finally it will touch on the effect of obstructive sleep apnea on immune response and the severity of COVID-19.

Seasonal variation and sleep patterns in a hot climate Arab Region.

PURPOSE: To describe the effect of seasonal variations on sleep patterns in a hot climate Arab region. METHODS: This is a cross-sectional study that included healthy Omani subjects of both genders between ages 18 and 59 years. Data for sleep pattern identification in summer and winter were collected from participants using an actigraphy wristband. RESULTS: Among 321 participants, in summer seasons, a polyphasic sleep pattern (40%) prevailed over other sleep patterns (P < 0.001). While in the winter season, monophasic sleep (31%) was the dominant pattern (P < 0.001). Subjects slept longer during the winter seasons with total hours of sleep during the day 48 min longer than in the summer, though the difference was not statistically significant (P > 0.05), while siesta duration in the summer was significantly longer (13 min, P < 0.01). In summer, the sleep quality was good (PSQI ≤ 5); however, it was poor (PSQI > 5) in winter (P < 0.05). Night sleep duration, daytime sleepiness, and sleep latency were not statistically different between the summer and winter seasons. CONCLUSION: Sleep patterns may be influenced by seasonal changes. A polyphasic sleep pattern prevailed in summer while a monophasic pattern was the predominant sleep pattern in winter. In summer, the sleep quality was good and the siesta duration was longer compared to the winter.

Pt-Based Nanostructures for Electrochemical Oxidation of CO: Unveiling the Effect of Shapes and Electrolytes.

Direct alcohol fuel cells are deemed as green and sustainable energy resources; however, CO-poisoning of Pt-based catalysts is a critical barrier to their commercialization. Thus, investigation of the electrochemical CO oxidation activity (COOxid) of Pt-based catalyst over pH ranges as a function of Pt-shape is necessary and is not yet reported. Herein, porous Pt nanodendrites (Pt NDs) were synthesized via the ultrasonic irradiation method, and its CO oxidation performance was benchmarked in different electrolytes relative to 1-D Pt chains nanostructure (Pt NCs) and commercial Pt/C catalyst under the same condition. This is a trial to confirm the effect of the size and shape of Pt as well as the pH of electrolytes on the COOxid. The COOxid activity and durability of Pt NDs are substantially superior to Pt NCs and Pt/C in HClO4, KOH, and NaHCO3 electrolytes, respectively, owing to the porous branched structure with a high surface area, which maximizes Pt utilization. Notably, the COOxid performance of Pt NPs in HClO4 is higher than that in NaHCO3, and KOH under the same reaction conditions. This study may open the way for understanding the COOxid activities of Pt-based catalysts and avoiding CO-poisoning in fuel cells.

pH Controlled Nanostructure and Optical Properties of ZnO and Al-Doped ZnO Nanorod Arrays Grown by Microwave-Assisted Hydrothermal Method.

The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications.

Association of elevated glycated hemoglobin and obesity with afternoon napping for more than 1 h in young and middle-aged healthy adults.

Introduction: Sleep has different patterns followed worldwide and can be influenced by social, cultural, and environmental factors. Daytime napping is commonly practiced in different parts of the world with controversial results of its effect on glucose metabolism. The current study aims to examine the association of afternoon napping and night sleep duration with metabolic derangements. Methods: This is a cross-sectional study involving young adults and middle-aged subjects. Anthropometric measurements were taken for height and weight and hip and waist ratio. Consented subjects were asked to wear actigraphy for 1 week and run their usual daily activities. Home sleep apnea testing was performed to exclude obstructive sleep apnea. Subjects had been asked to come fasting on day seven for blood collection to test for fasting glucose, glycated hemoglobin, lipid profile, and insulin. Results: A total of 405 subjects were involved to complete the study (52% male, 48% female). The mean age of participants was 32.8 ± 11.5 years. The study indicated that the duration of afternoon napping was significantly associated with abnormal glycated hemoglobin (HbA1c > 5.7%) (p = 0.01) and body mass index (p = 0.046) independent of age, gender, and nocturnal sleep duration. Nocturnal sleep duration was associated with increased insulin level (p = 0.04). Conclusion: Afternoon napping is associated with an increased level of glycated hemoglobin and obesity and that may predispose to the development of type 2 diabetes mellitus.

Some Distinct Attributes of ZnO Nanorods Arrays: Effects of Varying Hydrothermal Growth Time.

This study investigates the growth time effect on the structural, morphological, optical, and photoelectrochemical characteristics of highly oriented ZnO nanorod arrays (ZNRAs). The nanorod arrays were grown on ITO substrates using the unified sol-gel spin coating and hydrothermal techniques. ZnO nanoparticles (ZNPs) were synthesized using the sol-gel spin coating method. In contrast, the hydrothermal method was used to grow the ZnO nanorods. The hydrothermal growth time investigated was between 4 and 12 h. The synthesized ZNRAs were used as the photoanode electrodes to investigate their photoelectrochemical (PEC) electrode potency. The as-prepared ZNRAs were characterized using various analytical tools to determine their structures, morphologies, optical, and photoelectrochemical traits. EDX spectra showed the presence of uncontaminated ZnO chemical composition, and FTIR spectra displayed the various functional groups in the samples. A rod-shaped ZnO nanocrystallite with mean lengths and diameters of 300-500 nm and 40-90 nm, respectively, is depicted. HRTEM images indicated the nucleation and growth of ZNRAs with a lattice fringe spacing of 0.26 nm and a growth lattice planer orientation of [002]. The optimum ZNRAs (grown at 8 h) as photoelectrode achieved a photoconversion efficiency of 0.46% and photocurrent density of 0.63 mA/cm2, that was 17 times higher than the one shown by ZNPs with Ag/AgCl as the reference electrode. Both values were higher than those reported in the literature, indicating the prospect of these ZNRAs for photoelectrode applications.

Photoconversion efficiency of In2S3/ZnO core-shell heterostructures nanorod arrays deposited via controlled SILAR cycles.

This paper reports the structures, morphologies, optical properties, and photoconversion efficiency (η%) of the In2S3/ZnO core-shell heterostructures nanorod arrays (IZCSHNRAs) produced via the controlled successive ionic layer absorption and reaction (SILAR) cycles. As-produced samples were characterized using XRD, FESEM, TEM, UV-Vis, PL, XPS and FTIR techniques. The proposed IZCSHNRAs revealed nearly double photocurrent density and η% values compared to the pure ZnO nanorod arrays (ZNRAs). In addition, the light absorption, crystallinity and microstructures of the specimens were appreciably improved with the increase of the SILAR cycles. The deposited nanoparticles of In2S3 (ISNPs) on the ZNRAs surface was responsible for the improvement in the heterostructures, light absorption and photogenerated electron-hole pairs separation, thus enhancing the photoconversion performance. It is established that a simple SILAR approach can be very useful to produce good quality IZCSHNRAs-based photoelectrodes required for the future development of high performance photoelectrochemical cells (PECs).