Shiva Mohajernia

Shiva Mohajernia
Universität Siegen · Department of Chemistry and Biology

Doctor of Engineering

About

50
Publications
5,921
Reads
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963
Citations
Citations since 2016
45 Research Items
951 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
Additional affiliations
March 2015 - present
Friedrich-Alexander-University of Erlangen-Nürnberg
Position
  • PhD Student
September 2012 - September 2014
University of Tehran
Position
  • Master's Student
September 2007 - September 2011
Ferdowsi University Of Mashhad
Position
  • Bachelor student

Publications

Publications (50)
Article
Full-text available
H2 generation from photocatalytic water splitting is one of the most promising approaches to producing cost-effective and sustainable fuel. Nanostructured TiO2 is a highly stable and efficient semiconductor photocatalyst for this purpose. The main drawback of TiO2 as a photocatalyst is the sluggish charge transfer on the surface of TiO2 that can be...
Article
Single‐atom (SA) or single‐site catalysis (SACs) has over the past years become an increasingly fascinating topic in the catalysis field. SACs have allowed new approaches in heterogeneous catalysis, minimized the use of precious metals, and enabled an unprecedented control over atomistic effects, resulting in improved active sites, and at the same...
Article
The use of titanium dioxide (TiO 2 ) for photocatalytic applications has been intensively investigated for years due to appropriate electronic properties, chemical and photocorrosion resistance, as well as the low cost of the material [1]. Although TiO 2 has a suitable conduction band position for the photocatalytic H 2 formation reaction, the hydr...
Article
This mini-review summarizes the recent research on the applications of anodic one-dimensional suboxide titania nanostructures with enhanced electrodics properties by introducing atomic-scale defects into the titania systems. Due to the unique semiconductive properties of TiO2 nanostructures, so far, the main focus of research has been on photocatal...
Article
Metal-oxide surfaces have successfully been modified to elicit surface hydrophobicity via facile application of self-assembled monolayers (SAMs) using carbohydrate molecules comprising phosphonic acid groups. In this work, we shed light on the role of the functionalization technique used for surface modification of zirconia nanotubes (ZrNT) and com...
Article
Full-text available
Here we evaluate three different noble metal co-catalysts (Pd, Pt, Au) that are present as single atoms (SAs) on the classic benchmark photocatalyst, TiO2. To surface-trap the single atoms we introduced controlled surface vacancies (Ti³⁺-Ov) on anatase TiO2 nanosheets by a thermal reduction treatment. After anchoring identical loadings of single at...
Article
In the present research, we investigate the synergistic effects of Ru-doping and Ar/H2 reduction treatment on the PEC water splitting performance and hydrogen evolution rate of TiO2 nanotube arrays photoelectrodes. The Ti-Ru alloy with 0.2 at% Ru was used to grow anodic self-organized Ru-doped TiO2 nanotube layers. An ideal synergy between Ar/H2 re...
Article
Full-text available
The present work describes a self-assembling photocatalytic system that is observed when illuminating grey titania nanoparticles in suspension with a plain aqueous Ni²⁺ solution. Such a suspension (in contrast to white titania), under UV illumination, increasingly produces H2 from neutral water. We show that the origin of this self-activation is no...
Article
Developing ultraefficient electrocatalytic materials for the hydrogen evolution reaction (HER) with low content of expensive platinum group metals (PGMs) via low-energy-input procedures is the key to the successful commercialization of green water electrolysis technologies for sustainable production of high-purity hydrogen. In this study, we report...
Article
Full-text available
Titanium dioxide (TiO2) has been the benchmark semiconductor in photocatalysis for more than 40 years. Full water splitting, that is, decomposing water into H2 and O2 in stoichiometric amounts and with an acceptable activity, still remains a challenge, even when TiO2‐based photocatalysts are used in combination with noble metal co‐catalysts. The bo...
Article
Full-text available
Single‐atom (SA) catalysis is a novel frontline in the catalysis field due to the often drastically enhanced specific activity and selectivity of many catalytic reactions. Here, an atomic‐scale defect engineering approach to form and control traps for platinum SA sites as co‐catalyst for photocatalytic H2 generation is described. Thin sputtered TiO...
Preprint
Au and Pt do not form homogeneous bulk alloys as they are thermodynamically not miscible. However, we show that anodic TiO$_2$ nanotubes (NTs) can in-situ be uniformly decorated with homogeneous AuPt alloy nanoparticles (NPs) during their anodic growth. For this, a metallic Ti substrate containing low amounts of dissolved Au (0.1 at%) and Pt (0.1 a...
Preprint
Full-text available
Photocatalytic $H_2$ evolution reactions on pristine TiO$_2$ is characterized by low efficiencies due to trapping and recombination of charge carriers, and due to a sluggish kinetics of electron transfer. Noble metal (mainly Pt, Pd, Au) nanoparticles are typically decorated as cocatalyst on the TiO$_2$ surface to reach reasonable photocatalytic yie...
Preprint
Reduced titanium dioxide has recently attracted large attention, particularly for its unique co-catalyst-free H$_2$ heterogeneous photocatalytic application. The enhanced photocatalytic activity of the reduced TiO$_2$ was previously ascribed to the introduction of point crystal defects (mainly Ti$_3^+$ centers), which result in the formation of int...
Preprint
With a large-scale usage of portable electric appliances, a high demand for increasingly high density energy storage devices has emerged. MoO3 has, in principle, a large potential as negative electrode material in supercapacitive devices, due to high charge densities that can be obtained from its reversible redox reactions. Nevertheless, the extrem...
Preprint
Au nanoparticles at the TiO$_2$ surface can enhance the photocatalytic H$_2$ generation performances owing to their electron transfer co-catalytic ability. Key to maximize the co-catalytic effect is a fine control over Au nanoparticle size and placement on the photocatalyst, in relation to parameters such as the TiO$_2$ morphology, illumination wav...
Article
Full-text available
In this research, the effect of alkali metal cations including Li, Na and Cs in hydrothermal solution is investigated on the morphology, stability, and photoactivity of nanostructured TiO 2 nanoflakes as a photoanode. The TiO 2 nanoflakes are formed through hydrothermal treatment of Ti foil in 1.0 M LiOH, NaOH or CsOH at 100 °C for 3h. By subsequen...
Article
Reduced titanium dioxide has recently attracted large attention, particularly for its unique co-catalyst-free H2 heterogeneous photocatalytic application. The enhanced photocatalytic activity of the reduced TiO2 was previously ascribed to the introduction of point crystal defects (mainly Ti3+ centers), which result in the formation of intrinsic co-...
Thesis
Titanium dioxide (TiO2) has been the benchmark semiconductor on photocatalytic application for more than 40 years. It is chemically stable, environmentally friendly, earth abundant, and its electronic properties are suitable for functional applications in the field of photocatalysis. However, TiO2 has two inherent weaknesses. Firstly, its large ban...
Article
Full-text available
In the current energy scenario, electrochemical capacitors hold the promise to fulfil requirements of high power densities, short charging-discharging times, and long lifetimes. For such supercapacitors, MoO3 is one of the most potent candidate as a negative electrode material, due to a very high theoretical charge density ascribed to easily-switch...
Article
Full-text available
Recently, sodium ion batteries (SIBs) have been widely investigated as one of the most promising candidates for replacing lithium ion batteries (LIBs). For SIBs or LIBs, designing a stable and uniform solid electrolyte interphase (SEI) at the electrode–electrolyte interface is the key factor to provide high capacity, long‐term cycling, and high‐rat...
Article
With a large-scale usage of portable electric appliances, a high demand for increasingly high density energy storage devices has emerged. MoO3 has, in principle, a large potential as negative electrode material in supercapacitive devices, due to high charge densities that can be obtained from its reversible redox reactions. Nevertheless, the extrem...
Article
The primary focus of the paper is the fabrication of nanotubes via a two steps anodizing procedure on a TiZr substrate followed subsequent annealing treatments and their effect on surface and biocompatibility. The two step anodizing process is optimized for obtaining uniform and ordered nanotubular structures, that are then annealed in air or reduc...
Article
In the present work, we investigate the efficiency of TiO2 photoelectrode layers on boron‐doped diamond foil (BDDF) in comparison with a classic conducting glass (fluorine‐doped tin oxide, FTO) back contact. Crystalline thin TiO2 layers were prepared on the substrates by two different methods: (i) deposition of metallic Ti thin films followed by th...
Article
TiO2 nanostructures represent a key platform for biomedical applications, due to the combination of biocompatibility and high surface area. Especially TiO2 nanotube layers have been widely investigated due to controllable nanotopographic effects as well as for electrodes in electrostimulation experiments. In the present work we produce Ar/H2-reduce...
Article
Full-text available
In this work, we report on a facile and novel method for decorating titanium dioxide (TiO2) nanotubes with Rh nanoparticle‐nanonetworks that act as co‐catalysts in photocatalytic H2 generation. In a first step, a Ti‐Rh (0.2 at%) alloy is etched in Kroll’s solution leading to a dealloyed surface decorated with a Rh nanoparticle‐network of adjustable...
Article
Au nanoparticles at the surface of TiO2 can improve the photocatalytic H2 generation performances owing to their electron transfer co-catalytic ability. Key to maximize the co-catalytic effect is a fine control over Au nanoparticle size and placement on the photocatalyst, in relation to parameters such as the TiO2 morphology, illumination wavelengt...
Article
Full-text available
Recent work demonstrated that intrinsic Au nanoparticle decoration of TiO2 nanotube arrays (NTs) can be achieved by electrochemical anodization of Ti–Au alloy substrates. However, for a Ti–Au cast alloy produced by melt-alloying, the Au concentration cannot exceed the solubility limit of Au in Ti of 0.2 at.% – this sets constraints on the intrinsic...
Article
Full-text available
Cu‐doping in titania is usually detrimental to the material’s photoconductivity which prevents the use of this combination in photoanodes. In this work, we produce TiO2 nanotube arrays intrinsically doped with copper and establish sufficient conductivity to use them as efficient photoanodes for methanol oxidation in a photoelectrochemical hydrogen...
Article
In this work, we grow intrinsically Cu-doped TiO2 nanotubes (TiNTs) by self-organizing anodization of Ti–Cu binary alloys. We demonstrate that up to a copper concentration of 1.5 at.% in the alloy, self-ordered Cu2+-doped nanotubes can be grown. Under UV illumination the Cu2+ ion-doped oxide structures can be converted to nanotubes that carry metal...
Article
In the present work, we report the use of TiO2 nanotube (NT) layers with a regular intertube spacing that are decorated by Pt nanoparticles through the atomic layer deposition (ALD) of Pt. These Pt‐decorated spaced (SP) TiO2 NTs are subsequently explored for photocatalytic H2 evolution and are compared to classical close‐packed (CP) TiO2 NTs that a...
Article
Full-text available
Titania is one of the key materials used in 1D, 2D, and 3D nanostructures as electron transport media in energy conversion devices. In the present study, it is shown that the electronic properties of TiO2 nanotubes can be drastically improved by inducing a nanotwinned grain structure in the nanotube wall. This structure can be exclusively induced f...
Article
Full-text available
Solutions that simulate hydrometallurgical base metal process streams with high nickel (Ni) and minor platinum (Pt) concentrations were used to create Pt/Ni nanoparticles on TiO2 nanotube surfaces. For this, electrochemical deposition – redox replacement (EDRR) was used that also allowed to control the nanoparticle size, density and Pt/Ni content o...
Article
Au and Pt do not form homogeneous bulk alloys as they are thermodynamically not miscible. However, we show that anodic TiO2 nanotubes (NTs) can in-situ be uniformly decorated with homogeneous AuPt alloy nanoparticles (NPs) during their anodic growth. For this, a metallic Ti substrate containing low amounts of dissolved Au (0.1 at%) and Pt (0.1 at%)...
Article
Photocatalytic H2 evolution reactions on pristine TiO2 is characterized by low efficiencies due to trapping and recombination of charge carriers, and due to a sluggish kinetics of electron transfer. Noble metal (mainly Pt, Pd, Au) nanoparticles are typically decorated as cocatalyst on the TiO2 surface to reach reasonable photocatalytic yields. Howe...
Article
Full-text available
Among several parameters that affect the yield of a photocatalytic process mediated by a metal oxide semiconductor, key is the efficient separation and transfer of photo-generated charge carriers. To overcome kinetic limitations and enable charge transfer, an effective strategy is to decorate the photocatalyst surface with cocatalytic nanoparticles...
Article
To control the degradation of magnesium alloys and improve the mechanical performance of common hydroxyapatite (HAp) coatings, a HAp coating containing multi-walled carbon nanotubes (MWCNT) was applied on AZ31 magnesium alloy using plasma spray technique. The coating properties including thickness and morphology, phase analysis and toughness were c...
Article
Full-text available
In this work we study the depth composition of anodic TiO2 nanotube layers. We use elemental depth profiling with Glow Discharge Optical Emission Spectroscopy and calibrate the results of this technique with X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). We establish optimized sputtering conditions for nanotubular...
Article
Full-text available
Over the past years, α‐Fe2O3 (hematite) has re‐emerged as a promising photoanode material in photoelectrochemical (PEC) water splitting. In spite of considerable success in obtaining relatively high solar conversion efficiency, the main drawbacks hindering practical application at hematite are related to an intrinsically hampered charge transport a...
Article
Full-text available
In the present work we report on TiO 2 nanotube arrays (TNTAs) that were converted to a conductive scaffold established via an optimized reduction treatment in Ar/H 2. These conductive TNTAs are then employed for RuO 2 nanoparticle decoration. The effect of the Ar/H 2 treatment is evaluated by electron energy loss spectroscopy (EELS) and electron p...
Article
Full-text available
In the present work we report on the key factors dictating the photo-electrochemical (PEC) performance of suboxide titania (TiOx) nanotubes. TiOx nanotubes were produced by a systematic variation of reduction heat treatments of TiO2 in Ar/H2. The properties of the TiOx tubes were investigated by electron paramagnetic resonance (EPR), transmission e...
Article
Full-text available
In the present work we investigate the effect of the surface electrokinetic properties and presence of background ions on the flow of a marker dye through TiO2 nanotube membranes. We believe the results to be of high significance not only for filtration but also for the design of microphotoreactor application based on photoactive TiO2 nanotubes mem...
Article
Inhibitive performance of a new thiazolo-pyrimidine derivative has been investigated on mild steel in a solution of 1 M H2SO4. Electrochemical measurement, scanning electron microscope analysis and quantum chemical calculations are the tests and methods used to assess the performance of the inhibitors. The results indicate that the thiazolo-pyrimid...
Article
This research covers a different microstructural and electrochemical investigation on hydroxyapatite (HAP) coatings deposited on AZ31 magnesium alloy. Microstructure characterization and functional group identification were performed using X-ray diffraction (XRD), Fourier transform infrared and scanning electron microscopy (SEM) techniques. The pre...
Article
To control the degradation of Magnesium alloys, uniform nano-hydroxyapatite (n-HAP) coating was applied on AZ31 Magnesium alloy using both direct and pulse voltage electrodeposition methods. The in vivo corrosion of AZ31 with n-HAP coating was investigated by electrochemical tests. The results showed that by the pulse electrodeposition method brush...
Article
nanohydroxyapatite (n-HAP) was coated on to AZ31 magnesium alloy in order to reduce the surface corrosion rate and enhance the bio-compatibility. N-HAP was successfully coated by pulse electrodeposition technique. Morphology and composition of the coatings were investigated by scanning electron microscopy and X-ray diffraction methods, respectively...
Article
In this study, the inhibitive effect of synthesized 1-(7-methyl-5-morpholin-4-yl-thiazolo[4,5-d]pyrimidin-2-yl)-hydrazine (MMTPH) as a new corrosion inhibitor for mild steel in 0.5 M sulfuric acid medium is investigated employing potentiodynamic polarization, electrochemical impedance spectroscopy and linear polarization resistance techniques. The...

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Project (1)
Project
Goal: Special Issue on Catalysts (ISSN 2073-4344; CODEN: CATACJ), MDPI Open Access Journal (IF = 4.146, http://www.mdpi.com/journal/catalysts) link: https://www.mdpi.com/journal/catalysts/special_issues/ISPEWS Guest Editors: Dr. Shiva Mohajernia (shiva.mohajernia@uni-siegen.de) Prof. Dr. Manuela Killian (manuela.killian@uni-siegen.de) Dr. Anca Mazare (anca.mazare@fau.de) Deadline for manuscript submission: 20 June 2022