Value and Limitations of Urethrotech Catheterisation Device to Manage Difficult Urethral Catheterisation in Male Spinal Cord Injury Patients.

Methods: We used a Urethrotech catheterisation device in 57 male patients with spinal cord injury, in whom urethral catheterisation was unsuccessful or previous catheterisation was difficult. Results: Urethrotech catheter could be inserted in 51 patients. No patient developed urinary tract infection. In one patient, the guidewire could not be introduced into the bladder, and a coude Foley catheter was inserted. In two patients, the guidewire was inserted into the bladder, but a 16 CH catheter could not be advanced over the guidewire. Emergency suprapubic cystostomy was performed in one case; in the other, urethral stricture was dilated; a size 12 CH catheter was inserted. In three patients, the guidewire curled back into the urethra because of severe spasm of the urethral sphincter. Catheterisation with a Tiemann catheter was successful after administration of diazepam and/or stretching of the anal sphincter by another health professional, which caused reflex relaxation of the urethral sphincter. Complications of Urethrotech catheterisation included urethral bleeding, haematuria, pain, doubling back of the guidewire due to spasm of the urethral sphincter or from an empty bladder. We adopted variations in technique, eg filling the bladder with saline prior to catheterisation when feasible, insertion of the guidewire by the side of the old catheter, use of Tiemann tip catheters, administration of antibiotics, diazepam to control spasms, nifedipine to control autonomic dysreflexia, analgesics, stretching of the anal sphincter to induce reflex relaxation of the urethral sphincter, urgent imaging studies to confirm correct positioning of the catheter, omitting anticoagulants and monitoring patients, who developed bleeding. Conclusion: Use of Urethrotech in spinal injury patients warranted adaptations to the technique, which required expertise, experience, and backup facilities. To ensure patient safety, Urethrotech catheter should be used in a hospital setting, and by medical personnel with experience in the management of spinal cord injury patients.

Delay in diagnosis of urethral perforation due to catheterisation in a person with cervical spinal cord injury. Importance of (1) imaging studies done promptly for detection and documentation of urethral trauma, (2) Urethrotech catheterisation device to minimise urethral trauma and achieve successful catheterisation: A case report.

INTRODUCTION AND IMPORTANCE: Spinal cord injury patients are at risk for urethral trauma during catheterisation. We report a patient in whom urethral perforation due to catheterisation was not recognised for ∼ four days. CASE PRESENTATION: Following a routine catheter change by community nurses in a male person with tetraplegia, the catheter drained only a small amount of urine. Therefore, the patient attended the hospital where the staff removed the catheter but could not place a new catheter. The doctor tried different catheters and on fifth attempt, inserted a catheter. The patient continued to bypass urine and was prescribed Solifenacin. On self-referral to spinal unit, urethral trauma was suspected. CT of pelvis revealed the balloon of the Foley catheter in the penile urethra at penis base with the tip projecting beyond the penile shaft. Suprapubic cystostomy was done. The patient continued to leak urine from the penis; required penile sheath drainage and an additional leg bag. CLINICAL DISCUSSION: This case illustrates the value of CT of pelvis including the penis in detecting urethral trauma and misplacement of the catheter. Physicians should look for symptoms and signs of urethral trauma and incorrect positioning of the catheter. Imaging studies should be done without delay to assess urethral trauma and misplacement of urinary catheter. CONCLUSION: We use Urethrotech urethral catheterisation in patients in whom the first attempt to insert a catheter per urethra is unsuccessful, or in patients with a history of difficult catheterisation. This helped to minimise urethral trauma and achieve successful catheterisation.

Milk of calcium in renal calyces, renal pelvis, and ureter in a person with tetraplegia.

Milk of calcium is a colloidal suspension of precipitated calcium salts which lies in a dependent manner and imaging reveals a horizontal upper edge. We report a 44-year-old male person with tetraplegia, who had been staying in bed for prolonged periods due to ischial and trochanteric pressure sores. Ultrasound scan of the kidneys revealed numerous variable-sized stones in the left kidney. CT of abdomen showed stones in the left kidney with dense layering of calcific material in a dependent distribution assuming the shape of the renal pelvis and the calyces. CT images in axial and corresponding sagittal views showed milk of calcium exhibiting a fluid level in the renal pelvis and calyces and the ureter. This is the first report of milk of calcium detected in the renal pelvis and calyces as well as in the ureter of a person with spinal cord injury. Following insertion of a ureteric stent, the milk of calcium in the ureter drained partly but the renal milk of calcium persisted. The renal stones were pulverized by ureteroscopy and LASER lithotripsy. Follow-up CT of kidneys performed 6 weeks after surgery showed the milk of calcium in the left ureter had drained, but there was no significant change of the left sizeable branching pelvi-calyceal stone regarding its extension and density.

Possible Use of a Safety-Valve with a Foley Catheter During Catheterisation of Male Spinal Cord Injury Patients for Prevention of Urethral Trauma Caused by Inflation of the Catheter Balloon in the Urethra.

We used a safety-valve (Trans-Urethral Catheterisation Safety Valve, Class Medical, Limerick, Ireland) to prevent urethral trauma due to inflation of the anchoring balloon in the urethra during catheterisation of male spinal cord injury patients in a spinal unit. The safety-valve is attached to the balloon channel of a Foley catheter. If the balloon is inflated when it is in the urethra, the pressure valve is activated. Any fluid pushed into the balloon channel leaks out and balloon inflation stops, indicating that the balloon is not inside the bladder. The safety-valve was used in 44 catheterisations. There was leakage of water during three catheterisations. In the first case, the health professional did not inflate and deflate the balloon prior to its use. This "pre-valve inflation" step overcomes the baseline resistance pressure of the balloon and prevents fluid leaking from the valve when the catheter is in the correct position. In the second instance, the valve was found to be defective. In the third case, the catheter had been misplaced; it was removed and repositioned; there was no leakage of water during inflation of the balloon. In one out of 44 catheterisations, the catheter had been misplaced; leakage of water from the safety-valve stopped inflation of the balloon and prevented iatrogenic urethral trauma. The safety-valve may be used during catheterisation of male patients in the spinal unit to prevent urethral trauma caused by inflation of the balloon of Foley catheter in the urethra. However, health professionals should remember the few shortcomings of the catheter safety-valve.

Inactivation of SARS-CoV-2 and Other Human Coronaviruses Aided by Photocatalytic One-Dimensional Titania Nanotube Films as a Self-Disinfecting Surface.

SARS-CoV-2 and its variants that continue to emerge have necessitated the implementation of effective disinfection strategies. Developing self-disinfecting surfaces can be a potential route for reducing fomite transmissions of infectious viruses. We show the effectiveness of TiO2 nanotubes (T_NTs) on photocatalytic inactivation of human coronavirus, HCoV-OC43, as well as SARS-CoV-2. T_NTs were synthesized by the anodization process, and their impact on photocatalytic inactivation was evaluated by the detection of residual viral genome copies (quantitative real-time quantitative reverse transcription polymerase chain reaction) and infectious viruses (infectivity assays). T_NTs with different structural morphologies, wall thicknesses, diameters, and lengths were prepared by varying the time and applied potential during anodization. The virucidal efficacy was tested under different UV-C exposure times to understand the photocatalytic reaction's kinetics. We showed that the T_NT presence boosts the inactivation process and demonstrated complete inactivation of SARS-CoV-2 as well as HCoV-OC43 within 30 s of UV-C illumination. The remarkable cyclic stability of these T_NTs was revealed through a reusability experiment. The spectroscopic and electrochemical analyses have been reported to correlate and quantify the effects of the physical features of T_NT with photoactivity. We anticipate that the proposed one-dimensional T_NT will be applicable for studying the surface inactivation of other coronaviruses including SARS-CoV-2 variants due to similarities in their genomic structure.

Value of serial ultrasound imaging in conservative management of epididymo-cutaneous fistula in a person with cervical spinal cord injury.

Epididymo-cutaneous fistula was seen in a person with cervical spinal cord injury and neuropathic bladder. This patient developed left epididymitis; then he formed an abscess superficial to the tail of the epididymis, which burst open to the skin discharging pus; subsequently, this progressed to epididymo-cutaneous fistula. A few drops of urine would leak through the fistula. The carers kept a dressing over the fistula to collect the small amount of urine leak and changed the dressing daily. This patient's carers squeezed any subcutaneous collection and drained the pus through the fistula. Serial ultrasound imaging of the scrotum was performed to guide the clinical management: (1) any subcutaneous abscess detected by the ultrasound scan was drained promptly; (2) ultrasound scans confirmed absence of any pathology in the testis; (3) the course of the disease was monitored as chronic epididymitis with echogenic debris in epididymal tail progressed to development of epididymo-cutaneous fistula and later to a chronic fistula with a matured tract. The serial scans revealed thickened tail of the left epididymis with heterogenous echo texture with no abscess formation, which encouraged the continuation of conservative management over a 5-year period while maintaining good quality of life. At the last follow-up in June 2022, leakage of urine from the epididymo-cutaneous fistula was observed very infrequently (once a month).

Large amounts of debris in the neuropathic bladder in persons with spinal cord injury; value of ultrasound scan in detection and management of vesical debris.

Persons with spinal cord injury are at risk for developing debris in the neuropathic bladder. Ultrasound scan of the urinary bladder helps to (1) detect debris, (2) differentiate debris from other bladder lesions, (3) alert the spinal cord physician to review bladder management, and (4) monitor the effect of various treatment regime to clear the debris. We present 4 cases to illustrate the sonographic appearances of debris in the neuropathic bladder and how treatment plans tailored to the needs of the individual patient helped to clear the debris.

Nephrogenic metaplasia in a female person with spinal cord injury: chronic irritation caused by Foley balloon was aggravated by a large uterine fibroid pressing upon the bladder wall for several years: a case report.

INTRODUCTION: Chronic irritation caused by urinary catheter may predispose to metaplastic changes in the bladder and very rarely, nephrogenic metaplasia. CASE PRESENTATION: A 53-year-old lady with T-2 paraplegia and urethral catheter drainage for 27 years presented with haematuria. MRI of pelvis, performed seven years ago, showed a 10 cm intramural fibroid within the anterior aspect of the uterine body which was pushing the collapsed urinary bladder containing the Foley catheter to the left. The patient decided to avoid surgery to remove the fibroid at that time. Ultrasound scan of the urinary bladder done now, revealed a polypoidal lesion in the left superolateral wall. Superficial enhancing lesion with no invasion of the bladder wall was seen in the CT urography. Cystoscopy showed extensive catheter reaction, and in the centre, a slightly more papillary area, which was resected. Histology revealed inflamed bladder mucosa showing tubular and papillary structures lined by cuboidal epithelial cells; the features were of nephrogenic metaplasia. The tubular and papillary structures were lined by cells showing positive immunohistochemical staining for CK7 and PAX8. DISCUSSION: Catheter reaction and nephrogenic metaplasia was found in the left superolateral wall of the bladder where the large uterine fibroid was pushing the balloon of the catheter against the bladder wall for more than seven years. The patient decided to undergo surgery to remove the large fibroid and thereby prevent further pressure effects upon the urinary bladder.

Boosting Photocatalytic Activity Using Reduced Graphene Oxide (RGO)/Semiconductor Nanocomposites: Issues and Future Scope.

Semiconductor nanoparticles are promising materials for light-driven processes such as solar-fuel generation, photocatalytic pollutant remediation, and solar-to-electricity conversion. Effective application of these materials alongside light can assist in reducing the dependence on fossil-fuel driven processes and aid in resolving critical environmental issues. However, severe recombination of the photogenerated charge-carriers is a persistent bottleneck in several semiconductors, particularly those that contain multiple cations. This issue typically manifests in the form of reduced lifetime of the photoexcited electrons-holes leading to a decrease in the quantum efficiency of various light-driven applications. On the other hand, semiconducting oxides or sulfides, coupled with reduced graphene oxide (RGO), have drawn a considerable interest recently, partly because of the RGO enhancing charge separation and transportation through its honeycomb sp2 network structure. High electron mobility, conductivity, surface area, and cost-effectiveness are the hallmark of the RGO. This Mini-Review focuses on (1) examining the approach to the integration of RGO with semiconductors to produce binary nanocomposites; (2) insights into the microstructure interface, which plays a critical role in leveraging charge transport; (3) key examples of RGO composites with oxide and sulfide semiconductors with photocatalysis as application; and (4) strategies that have to be pursued to fully leverage the benefit of RGO in RGO/semiconductors to attain high photocatalytic activity for a sustainable future. This Mini-Review focuses on areas requiring additional exploration to fully understand the interfacial science of RGO and semiconductor, for clarity regarding the interfacial stability between RGO and the semiconductor, electronic coupling at the heterojunction, and morphological properties of the nanocomposites. We believe that this Mini-Review will assist with streamlining new directions toward the fabrication of RGO/semiconductor nanocomposites with higher photocatalytic activity for solar-driven multifunctional applications.

Discitis following urinary tract infection manifesting as recurrent autonomic dysreflexia related to truncal movements in a person with tetraplegia.

A 44-year-old male person with tetraplegia (C-5 AIS-A (American Spinal Cord Injury Association Standard Neurological Classification of Spinal Cord Injury Impairment Scale)) developed urinary tract infection and received appropriate antibiotic. Subsequently, he started sweating and shivering when he was sitting up; these symptoms resolved while lying on his back. Autonomic dysreflexia triggered by truncal movements continued to occur for 3 months. CT of the spine showed L5-S1 discitis. MRI of the spine showed diffuse marrow oedema in L5 and S1 vertebrae and a large abscess at L5/S1 level. Blood culture yielded Serratia marcescens sensitive to meropenem. Meropenem followed by ertapenem was given for 12 weeks. After 11 months, MRI showed resolution of discitis and epidural collection. The patient was able to sit up for 9 hours without developing autonomic dysreflexia. If a person with cervical spinal cord injury develops posture-related autonomic dysreflexia (eg, in sitting position, lying on sides or while hoisted), disco-vertebral pathology should be suspected.

Inactivation of Human Coronavirus by Titania Nanoparticle Coatings and UVC Radiation: Throwing Light on SARS-CoV-2.

The newly identified pathogenic human coronavirus, SARS-CoV-2, led to an atypical pneumonia-like severe acute respiratory syndrome (SARS) outbreak called coronavirus disease 2019 (abbreviated as COVID-19). Currently, nearly 77 million cases have been confirmed worldwide with the highest numbers of COVID-19 cases in the United States. Individuals are getting vaccinated with recently approved vaccines, which are highly protective in suppressing COVID-19 symptoms but there will be a long way before the majority of individuals get vaccinated. In the meantime, safety precautions and effective disease control strategies appear to be vital for preventing the virus spread in public places. Due to the longevity of the virus on smooth surfaces, photocatalytic properties of "self-disinfecting/cleaning" surfaces appear to be a promising tool to help guide disinfection policies for controlling SARS-CoV-2 spread in high-traffic areas such as hospitals, grocery stores, airports, schools, and stadiums. Here, we explored the photocatalytic properties of nanosized TiO2 (TNPs) as induced by the UV radiation, towards virus deactivation. Our preliminary results using a close genetic relative of SAR-CoV-2, HCoV-NL63, showed the virucidal efficacy of photoactive TNPs deposited on glass coverslips, as examined by quantitative RT-qPCR and virus infectivity assays. Efforts to extrapolate the underlying concepts described in this study to SARS-CoV-2 are currently underway.

Engineered Solution-Liquid-Solid Growth of a "Treelike" 1D/1D TiO2 Nanotube-CdSe Nanowire Heterostructure: Photoelectrochemical Conversion of Broad Spectrum of Solar Energy.

This work presents a hitherto unreported approach to assemble a 1D oxide-1D chalcogenide heterostructured photoactive film. As a representative system, bismuth (Bi) catalyzed 1D CdSe nanowires are directly grown on anodized 1D TiO2 nanotube (T_NT). A combination of the reductive successive-ionic-layer-adsorption-reaction (R-SILAR) and the solution-liquid-solid (S-L-S) approach is implemented to fabricate this heterostructured assembly, reported in this 1D/1D form for the first time. XRD, SEM, HRTEM, and elemental mapping are performed to systematically characterize the deposition of bismuth on T_NT and the growth of CdSe nanowires leading to the evolution of the 1D/1D heterostructure. The resulting "treelike" photoactive architecture demonstrates UV-visible light-driven electron-hole pair generation. The photoelectrochemical results highlight: (i) the formation of a stable n-n heterojunction between TiO2 nanotube and CdSe nanowire, (ii) an excellent correlation between the absorbance vis-à-vis light conversion efficiency (IPCE), and (iii) a photocurrent density of 3.84 mA/cm2. This proof-of-concept features the viability of the approach for designing such complex 1D/1D oxide-chalcogenide heterostructures that can be of interest to photovoltaics, photocatalysis, environmental remediation, and sensing.

The risk of intra-urethral Foley catheter balloon inflation in spinal cord-injured patients: Lessons learned from a retrospective case series.

BACKGROUND: Inflating the balloon of Foley catheter in urethra is a complication of urethral catheterisation. We report five patients in whom this complication occurred because of unskilled catheterisation. Due to lack of awareness, the problem was not recognised promptly and patients came to harm. CASE SERIES: A tetraplegic patient developed pain in lower abdomen and became unwell after transurethral catheterisation. CT pelvis revealed full bladder with balloon of Foley catheter in dilated urethra.Routine ultrasound examination in an asymptomatic tetraplegic patient with urethral catheter drainage, revealed Foley balloon in the urethra. He was advised to get catheterisations done by senior health professionals.A paraplegic patient developed bleeding and bypassing after transurethral catheterisation. X-ray revealed Foley balloon in urethra; urethral catheter was changed ensuring its correct placement in urinary bladder. Subsequently, balloon of Foley catheter was inflated in urethra several times by community nurses, which resulted in erosion of bulbous urethra and urinary fistula. Suprapubic cystostomy was performed.A tetraplegic patient developed sweating and increased spasms following urethral catheterisations. CT of abdomen revealed distended bladder with the balloon of Foley catheter located in urethra. Flexible cystoscopy and transurethral catheterisation over a guide-wire were performed. Patient noticed decrease in sweating and spasms.A paraplegic patient developed lower abdominal pain and nausea following catheterisation. CT abdomen revealed bilateral hydronephrosis and hydroureter and Foley balloon located in urethra. Urehral catheterisation was performed over a guide-wire after cystoscopy. Subsequently suprapubic cystostomy was done. CONCLUSION: Spinal cord injury patients are at increased risk for intra-urethral Foley catheter balloon inflation because of lack of sensation in urethra, urethral sphincter spasm, and false passage due to previous urethral trauma. Education and training of doctors and nurses in proper technique of catheterisation in spinal cord injury patients is vital to prevent intra-urethral inflation of Foley catheter balloon. If a spinal cord injury patient develops bypassing or symptoms of autonomic dysreflexia following catheterisation, incorrect placement of urethral catheter should be suspected.

Effects of Carbon Allotrope Interface on the Photoactivity of Rutile One-Dimensional (1D) TiO2 Coated with Anatase TiO2 and Sensitized with CdS Nanocrystals.

The assembly of a large-bandgap one-dimensional (1D) oxide-conductive carbon-chalcogenide nanocomposite and its surface, optical, and photoelectrochemical properties are presented. Microscopy, surface analysis, and optical spectroscopy results are reported to provide insights into the assembly of the nanostructure. We have investigated (i) how the various carbon allotropes (C60), reduced graphene oxide (RGO), carbon nanotubes (CNTs), and graphene quantum dots (GQDs) can be integrated at the interface of the 1D TiO2 and zero-dimensional (0D) CdS nanocrystals; (ii) the carbon allotrope and CdS loading effects; (iii) the impact of the carbon allotrope presence on 0D CdS nanocrystals; and (iv) how they promote light absorbance. Subsequently, the functioning of the integrated nanostructured assembly in a photoelectrochemical cell has been systematically investigated. These studies include (i) chronoamperometry, (ii) impedance measurements or EIS, and (iii) linear sweep voltammetry. The results indicate that the presence of a GQD interface shows the most enhancement in the photoelectrochemical properties. The optimized photocurrent values were respectively noted to be 2.8, 2.2, 1.9, and 1.6 mA/cm(2), indicating JGQD > JRGO > JCNT > Jfullerene. Furthermore, the annealing conditions have indicated that ammonia treatment leads to an increase in the photoelectrochemical responses when using any form of the carbon allotropes.

Free energy dependence of pure phase iron doped bismuth titanate from first principles calculations.

A density functional theory study of Fe substitutions in Bi2Ti2O7 photocatalyst (Fe-BTO) is presented. It models an experiment where H2 production of Fe-BTO peaked for samples loaded with 1% Fe concentration then decreased for samples with heavier loadings. The total energy calculations were used to determine defect formation energies and the chemical potential landscape that suggests the observed formation of Fe2O3 (in samples at 2% Fe concentration) was detrimental to H2 production. Doping configurations as a function of oxygen chemical potential are discussed, and the chemical potential ranges that avoid formation of the Fe2O3 phase in Fe-BTO are predicted.

Doubling back of Foley catheter in urethra in a tetraplegic patient: delayed recognition.

A 51-year-old man with C-6 tetraplegia had ureteric calculi, developed ureteric stricture and required bilateral nephrostomy. Following change of the left nephrostomy, bloody urine was drained per nephrostomy. The urethral catheter was also changed; bloody drainage per urethral catheter was attributed to blood seeping from the left kidney. The length of the Foley catheter outside the penis appeared correct; therefore, it was presumed that the catheter had been introduced into the bladder. The following day, bladder washout could not be performed due to blockage of the catheter. CT of the kidneys and bladder revealed doubling back of the Foley catheter in the bulbar urethra with the balloon inflated in the urethra. The urethral catheter was removed and another catheter inserted satisfactorily by a senior doctor. From this experience we learned that a 'Long Catheter Sign' will not be positive if the catheter doubles back in the urethra. When in doubt, imaging studies should be performed immediately to check the position of the Foley catheter.

Encapsulating Bi2Ti2O7 (BTO) with reduced graphene oxide (RGO): an effective strategy to enhance photocatalytic and photoelectrocatalytic activity of BTO.

Multimetal oxides (AxByOz) offer a higher degree of freedom compared to single metal oxides (AOx) in that these oxides facilitate (i) designing nanomaterials with greater stability, (ii) tuning of the optical bandgap, and (iii) promoting visible light absorption. However, all AxByOz materials such as pyrochlores (A2B2O7)--referred to here as band-gap engineered composite oxide nanomaterials or BECONs--are traditionally prone to severe charge recombination at their surface. To alleviate the charge recombination, an effective strategy is to employ reduced graphene oxide (RGO) as a charge separator. The BECON and the RGO with oppositely charged functional groups attached to them can be integrated at the interface by employing a simple electrostatic self-assembly approach. As a case study, the approach is demonstrated using the Pt-free pyrochlore bismuth titanate (BTO) with RGO, and the application of the composite is investigated for the first time. When tested as a photocatalyst toward hydrogen production, an increase of ∼ 250% using BTO in the presence of RGO was observed. Further, photoelectrochemical measurements indicate an enhancement of ∼ 130% in the photocurrent with RGO inclusion. These two results firmly establish the viability of the electrostatic approach and the inclusion of RGO. The merits of the RGO addition is identified as (i) the RGO-assisted improvement in the separation of the photogenerated charges of BTO, (ii) the enhanced utilization of the charges in a photocatalytic process, and (iii) the maintenance of the BTO/RGO structural integrity after repeated use (established through reusability analysis). The success of the self-assembly strategy presented here lays the foundation for developing other forms of BECONs, belonging to perovskites (ABO3), sillenite (A12BO20), or delafossite (ABO2) groups, hitherto written off due to limited or no photoelectrochemicalactivity.

A unique architecture based on 1 D semiconductor, reduced graphene oxide, and chalcogenide with multifunctional properties.

A unique heterostructured optoelectronic material (HOM), consisting of a reduced graphene oxide (RGO) layer with spatially distributed CdS, suspended by zinc oxide (ZnO) nanorods, is presented. The key features of this HOM are the assembly of the components in a manner so as to realize an effective integration between the constituents and the ability to modify the electronic properties of the RGO. For the first time, the location of RGO (as a suspended layer) along with the tuning of its charge-transport properties (n-/p-type) and its influence on the photo(electro)chemical processes has been examined systematically by using this ZnO/RGO/CdS HOM as a case study. The n-type RGO interlayer facilitates >100 % increase in the photocurrent density and 25 % increase in the photodegradation of a dye, compared to ZnO/CdS, thus demonstrating its multifunctionality. At 3.2 mA cm(-2) , this HOM architecture helps to achieve the highest photocurrent density utilizing ZnO, RGO, and CdS as building blocks in any form. The work is significant for the following reasons: i) other one dimensional (1D) oxides/chalcogenides or 1D oxides/dyes may be designed with similar architectures; ii) HOMs with tunable optical absorbance and charge-transport properties could be realized; iii) related application areas (e.g., sensing or solar fuel generation) should be greatly benefited.

Role of reduced graphene oxide in the critical components of a CdS-sensitized TiO2 -based photoelectrochemical cell.

Nitrogen (N)-doped reduced graphene oxide (nRGO) is systematically incorporated into a TiO(2) -CdS photoelectrochemical (PEC) cell and its role is examined in the three main components of the cell: 1) the CdS-sensitized TiO(2) photoanode, 2) the cathode, and 3) the S(2-)/S(.-) aqueous redox electrolyte. The nRGO layer is sandwiched between TiO(2) nanorods (deposited by using a solvothermal method) and CdS (deposited by using the successive ionic-layer-adsorption and -reaction method). Scanning electron microscopy with energy dispersive X-ray analysis (EDS) reveals the spatial distribution of CdS and nRGO, whereas nRGO formation is evident from Mott Schottky analysis. Chronoamperometry and PEC analysis indicate that upon incorporation of nRGO, a photocurrent density that is at least 27 times higher than that of pristine TiO(2) is achieved; this increase is attributable to the ability of the nRGO to efficiently separate and transport charges. Stability analysis performed by continuous photoillumination over ∼3 h indicates a 26% and 42 % reduction in the photocurrent in the presence and absence of the nRGO respectively. Formation of SO(4)(2-) is identified as the cause for this photocurrent reduction by using X-ray photoelectron spectroscopy. It is also shown that nRGO-coated glass is as effective as a Pt counter electrode in the PEC cell. Unlike the benefits offered by nRGO at the anode and cathode, introducing it in the redox electrolyte is detrimental. Systematic and complementary electrolyte and film-based studies on this aspect reveal evidence of the capacitive behavior of nRGO. Competition between the nRGO and the oxidized electrolyte is identified, based on linear-sweep voltammetry analysis, as the limiting step to efficient charge transport in the electrolyte.

Photoassisted enhancement of the electrocatalytic oxidation of formic acid on platinized TiO2 nanotubes.

A solvothermal method is used to deposit Pt nanoparticles on anodized TiO2 nanotubes (T_NT). Surface characterization using SEM, EDX, and XRD indicates the formation of polycrystalline TiO2 nanotubes of 110 ± 10 nm diameter with Pt nanoparticle islands. The application of the T_NT/Pt photoanode has been examined toward simultaneous electrooxidation and photo(electro)oxidation of formic acid (HCOOH). Upon UV-vis photoillumination, the T_NT/Pt photoelectrode generates a current density of 72 mA/cm(2), which is significantly higher (∼39-fold) than that of the T_NT electrode (1.85 mA/cm(2)). This boosting in the overall current is attributable to the enhanced oxidation of formic acid at the T_NT/Pt-electrolyte interface. Further, a series of cyclic voltammetric (CV) responses, of which each anodic scan is switched to photoillumination at a certain applied bias (i.e., 0.2 V, 0.4 V, etc.), is used to identify the role of T_NT/Pt as a promoter for the photoelectrooxidation of formic acid and understand a carbon monoxide (CO)-free pathway. Chronoamperometric (j/t) measurements demonstrate the evidence of an external bias dependent variation in the time lag during the current stabilization. An analysis of the CV plots and j/t profiles suggests the existence of both the charge-transfer controlled process and the diffusion-controlled process during formic acid photoelectrooxidation.