Photoelectrochemical water oxidation properties of bismuth vanadate photoanode irradiated by swift heavy ions

Photoelectrochemical (PEC) water splitting is a promising route for solar energy harvesting and storage. The most challenging obstacle for efficient water splitting is development of catalysts for oxygen evolution reaction (OER). Monoclinic bismuth vanadate (BiVO4, BVO) stands out as an excellent photoanode material due to its high stability in near-neutral electrolytes, suitable band structure and low-cost synthesis. However, pronounced charge recombination is a huge limiting factor and understanding the effects contributing to it is important for further improvements. In present study, we report the effect of swift heavy ion (SHI) irradiation (Xe, 150 MeV, 1 × 1010 – 5 × 1011 ions cm-2 ) on physicochemical properties of hydrothermally synthesized BVO thin films. X-ray diffraction (XRD) study showed that irradiated material preserved initial monoclinic scheelite phase and preferential growth along [010] direction together with the presence of notable amorphization at the highest fluence. Scanning electron microscopy (SEM) of all samples showed prismatic grains with an average size of 600 nm with the appearance of ion tracks after irradiation. More detailed examination of 1 × 1010 ions cm-2 irradiated sample by transmission electron microscopy (TEM) revealed presence of amorphous ion tracks (~ 10 nm in diameter) and hillocks at the BVO surface (~ 10 nm in height). Raman spectra showed bands that correspond to the monoclinic scheelite phase as well as the presence of new bands for 5 × 1011 ion cm-2 irradiated sample at 420 and 915 cm-1 that originate from complex vanadium oxides. X-ray photoelectron spectroscopy (XPS) after SHI irradiation showed an increase of V4+ states and oxygen vacancies, especially at higher fluences. Diffuse reflectance spectroscopy (DRS) measurements showed decrease of band gap with the increase of fluence. Photocurrent densities, obtained from 1-hour-long chronoamperometry measurements, showed that irradiation with 1 × 1010 ions cm-2 fluence leads to gradual recovery of PEC oxygen evolution with time. XRD, SEM and XPS measurements performed after PEC reveal complex changes in the BVO, including dissolution of the material along ion tracks.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Physicochemical properties of bismuth vanadate photoanode irradiated by swift heavy ions

Program and book of abstracts / 2nd International Conference on Innovative Materials in Extreme Conditions i. e. (IMEC2024), 20-22 March 2024 Belgrade, Serbia

The effect of swift heavy ion irradiation on physicochemical properties of monoclinic bismuth vanadate

Monoclinic bismuth vanadate (BiVO4) is considered to be one of the most promising photoanode materials for photoelectrochemical (PEC) water splitting due to its suitable band gap and band structure, good stability and low-cost synthesis. However, BiVO4 has poor charge transfer properties due to the high rate of electron-hole recombination and understanding the effects contributing to it is important for further improvements. Herein, we report the effect of swift heavy ion irradiation (Xe, 150 MeV, 1010 – 5×1011 ions/cm2 ) on physicochemical properties of hydrothermally synthesized BiVO4 thin films. X-ray diffraction study (XRD) showed that irradiated material preserved initial monoclinic scheelite crystal phase and preferential growth along [010] direction. As the fluence increased, a shift of the diffraction maxima towards lower 2θ values was observed indicating increased interplanar distances. Also, for the 5×1011 ions/cm2 irradiated sample, high degree of amorphization was noticed. Scanning electron microscopy (SEM) of all samples showed prismatic grains with an average size of 600 nm. In irradiated samples formation of ion tracks, ~10 nm in diameter, was observed. X-ray photoelectron spectroscopy (XPS) analysis of Bi 4f, V 2p and O 1s states showed that, after irradiation, increased amounts of V4+ and oxygen in the form of hydroxide occurred, especially at higher fluences. By using UV-Vis Diffuse Reflectance spectroscopy we showed that band gap decreased with the increase of fluence. Photocurrent densities obtained from linear sweep voltammetry indicated that irradiation with fluences higher than 1010 ions/cm2 have a notable negative effect on PEC oxygen evolution reaction. However, 1-hour-long chronoamperometry measurements of 1010 ions/cm2 irradiated sample revealed an increase of photocurrent densities. In order to get a better insight into preceding phenomena, we performed XRD, SEM and XPS analysis after PEC process

Utilization of swift heavy ions for modification of graphene oxide-based nanocomposites

Program and book of abstracts / 2nd International Conference on Innovative Materials in Extreme Conditions i. e. (IMEC2024), 20-22 March 2024 Belgrade, Serbia

Influence of N5+ ion irradiation on physicochemical properties of bismuth vanadate

Photoelectrochemical (PEC) cells for solar-energy conversion have received huge interest as a promising technology for renewable energy production. For the efficient application of such cells, it is necessary to develop adequate photoelectrodes. Recently, bismuth vanadate (BiVO4) has emerged as a promising photoanode due to its visible light harvesting properties, band edge positions and low-cost of synthesis. In this study, the effects of N5+ ion irradiation (75keV, 2 × 1014 and 4 × 1014 ions/cm2 ) on physicochemical properties of hydrothermally synthesized BiVO4 thin films were examined. From X-ray diffraction (XRD) study can be concluded that initial monoclinic material didn’t sustain any phase transition after irradiation. Also, preferential orientation remained dominantly along [010] direction with a slightly increasing share of [121] oriented growth, especially after irradiation with 2 × 1014 ions/cm2 . XRD measurements showed shift towards the higher 2θ after irradiation which indicates that interplanar distances decreases. The highest level of crystallinity was observed for the sample irradiated with fluence of 4 × 1014 ions/cm2 . Scanning electron microscopy (SEM) revealed prismatic morphology of all samples with an average grain size of 600 nm without visible traces of irradiation.Raman spectroscopy confirmed presence of bands that correspond to the monoclinic scheelite phase. X-ray photoelectron spectroscopy (XPS) analysis of V 2p confirmed presence of V5+ and V4+ while analysis of O 1s confirmed presence of oxygen in the form of lattice oxygen and in the form of hydroxide. UV-Vis Diffuse Reflectance spectroscopy revealed that calculated band gap decreases with the increase of fluence

The relationship between physical performance and alcohol consumption levels in Russian adults

Investigating the relationship between alcohol consumption and physical performance, we used data from the 2015–2018 Know Your Heart study on 4215 adults aged 35–69 from Arkhangelsk and Novosibirsk, Russia. We classified participants’ drinking status into non-drinking, non-problem drinking, hazardous drinking, and harmful drinking based on their self-reported drinking behaviors. To evaluate physical performance, we developed a Composite Physical Performance Scale (CPPS), which combined the results of three functional tests: grip strength (GS), closed-eyes balance, and chair rises (CR). We applied multivariable linear regression to assess the relationship between alcohol consumption and CPPS score, and ordinal logistic regression to explore the associations between alcohol consumption and the three functional tests separately. The results showed that harmful drinking was associated with lower CPPS scores compared to non-problem drinking. Among harmful drinking men, the decrease in CPPS scores was explained by all three tests equally and exceptionally by GS among women. Non-drinking was also associated with decreased CPPS, linked to lower GS and CR scores in men, and only lower GS scores in women. The study revealed a reduced physical performance in the non-drinking and harmful drinking groups compared to non-problem drinking

The impact of swift heavy ion irradiation on bismuth vanadate photoanode for photoelectrochemical water oxidation

The 27st International Scientific Conference of Young Scientists and Specialists (AYSS-2023); Oct 30 - Nov 3, 2023, JINR, Dubna, Russi

The quantitative damage and impurity depth profiling of the MgO single crystal

Ion implantation is frequently used method for the simulation of material damage caused by its exposure to harsh environments. The induced material damage and impurities accumulation will exhibit strong depth dependency in the case of its exposure to charged particles due to particle energy losses mechanisms. In presented study, we have performed an ion implantation of 4 MeV C3+ ions with three different fluences (1.5, 5 and 10 × 1015 cm−2) in the MgO [100] crystal in order to simulate structural damage induced by energetic particles. The damage depth profiles have been obtained by Elastic Backscattering Spectrometry in channeling orientation (EBS/C) using 1.86 MeV protons. EBS/C spectra were analyzed with the in house developed phenomenological Channeling SIMulation (CSIM) code. In addition to the damage depth profiles, with the new upgraded version of CSIM, concentration depth profile of implanted atoms (impurities) have also been determined. EBS/C spectra obtained profiles have been compared with the results of depth-resolved (micro) Photoluminescence spectroscopy (μPL) of the implanted MgO crystal cross-section. EBS/C and μPL obtained profiles for all investigated samples show very good consistency. This opens up the possibility for usage of EBS/C method in material analysis of lighter than bulk impurity concentration profiling

Ion channeling implantation induced MgF2 crystal damage through the “eye” of photoluminescence spectroscopy

Magnesium fluoride (MgF2) single crystal has been widely used as a material for application in optics due to its excellent properties like birefringence, wide range of transparency and low refractive index. As such, MgF2 has been proposed for planar waveguide structures. Ion implantation method was frequently used for planar waveguide production due to its ability to modulate optical properties by introduction of impurities and defects in crystal lattice. In all optics fabrication processes, there are demands for a precise control of optical characteristics modulation and hence the need for precise distribution of implanted impurities and induced damage. In this study, 4 MeV C3+ ions with the fluence of 5×1015 ions/cm2 were implanted in (001) axial direction of MgF2 single crystal. In order to determine the damage depth distribution in the crystal sample, photoluminescence (PL) spectroscopy was proposed as a method of evaluation. PL spectroscopy was used as a convenient method for damage investigation of transparent and semi-transparent samples. The cross-section of the implanted zone was mapped with the step of 0.34 µm and the variations in the spectra were investigated. It was shown that intensity evolution of two prominent wide bands with the intensity maximums at about 590 nm and 733 nm can be used for damage depth distribution estimation. Comparing the relative changes of derivatives of the band’s intensities, data related to the damage depth distribution were obtained. Obtained distribution was compared with the SRIM calculation of displacement damage. Considering the difference in implantation direction, good agreement with SRIM results was obtained. As a consequence of ion channeling, it was shown that damage distribution is extended deeper (for about 20%)