| Defect-Engineered TiO2 Nanosheets Decorated with Rhenium Co-Catalysts: A Promising Photocatalyst for Hydrogen ProductionIn this work, we investigated the effect of Re species, derived from ammonium perrhenate (NH4ReO4), on the photocatalytic hydrogen production performance of TiO2 nanosheets (TiNSs). Simultaneously, oxygen vacancies were introduced into the TiNSs through thermal annealing in an Ar/H2 atmosphere to modify their electronic properties. Oxygen vacancies improve the band gap and charge carrier dynamics, which are critical for photocatalytic applications [4]. The Re species were chemically decorated on the TiNSs support to explore potential synergies between defect-engineered TiO2 and rhenium-based co-catalysts. The experimental procedure involved annealing TiNSs at various flow rates and exposure times to create varying levels of oxygen vacancies. The annealed TiNSs were dispersed in a 1 mM Re precursor solution, stirred, centrifuged, and dried. The Re@TiO2 TiNSs were then characterized through X-ray diffraction (XRD), filed-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Moreover, their photocatalytic hydrogen evolution performance was evaluated under UV illumination (λ = 365 nm) at 1, 3, 8, and 22 hours. Our results revealed a significant improvement in the photocatalytic hydrogen production when Re species were incorporated into the TiNSs annealed for 1 hour under a flow rate of 50 mL/min, where the highest hydrogen production of ~45000 ppm was observed after 22 hours of illumination, which is more than 50 times higher than that of the pristine samples. This enhancement can be attributed to the synergy between the oxygen vacancies in TiNSs and the Re species, which acted as efficient electron sinks to suppress charge recombination and facilitate hydrogen evolution. However, prolonged annealing at 2 and 4 hours decreased performance, likely due to excessive defect formation or agglomeration of Re species. In conclusion, this study demonstrates the potential of rhenium-based co-catalysts in combination with defect-engineered TiNSs for photocatalytic hydrogen production for the first time. This work opens new avenues for utilizing Re-based materials as effective co-catalysts for TiO2 and other semiconductor systems in sustainable hydrogen production applications. University of Alberta | Activity | 2025-05-18 | "Tooba Mahmood", Sadegh Pourali, Mohajernia, S. |
| Defect-Engineered TiO2 Supports for Pt Single-Atom Catalysts: Insights into HER from DFT CalculationsDespite experimental progress in this field, a comprehensive understanding of the relationship between surface defects and SACs stabilization remains elusive, particularly from a Density Functional Theory (DFT) perspective [4]. In this study, first-principles DFT calculations, including energy band structures, density of states (DOS and PDOS), charge density distributions, and Gibbs free energy diagrams for the hydrogen evolution reaction (HER), are performed on both pristine and defect-engineered TiO2 surfaces hosting Pt single atoms (SAs) and clusters. The results reveal that oxygen vacancies play a critical role in optimizing the free energies of intermediates during the HER process on Pt SAs@TiO2. These defects effectively modulate the adsorption and desorption behavior of reaction intermediates, ultimately accelerating the catalytic kinetics. This work bridges the knowledge gap by offering detailed atomic-scale insights into the interplay between surface defects and SAC stabilization, paving the way for the rational design of efficient catalysts for hydrogen production. University of Alberta | Activity | 2025-05-18 | Sadegh Pourali, "Sina Hejazi", Mohajernia, S. |
| Effect of Ultrasound-Induced Defects on Photocatalytic Hydrogen Evolution in Anatase Titania Nanotubes Decorated with Platinum Single AtomsAnatase TiO2 nanotubes synthesized via electrochemical anodization using a typical organic electrolyte are a promising candidate for photocatalytic H2 evolution. Despite the wide optical bandgap and low catalytic activity of TiO2, which impede its performance, our approach enhances photocatalytic properties through the introduction of platinum (Pt) single atoms (SAs) as a co-catalyst and simultaneously surface engineering by making defects, significantly enhancing its photocatalytic properties. This work shows photoanode TiO2 nanotubes (TiNT) have excellent harvesting properties for Pt SAs from a dilute hexachloroplatinic acid solution. Optimally annealed TiNTs provide surface Ti3+ suitable for anchoring SA species directly from the solution. The treated TiO2 nanotubes were characterized by field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and photochemical hydrogen evolution. In the present study, we describe modifying the TiO2 nanotubes by loading Pt as a co-catalyst by simple immersion into dilute Pt solutions and defects by different intensities of high-power sonochemical treatment to enhance the photocatalytic hydrogen reaction rates. These findings show that ultrasound-treated TiNTs provide a remarkable substrate for SA decoration from dilute solutions aligned with promising performance, high H2 evolution catalysis, and renewable energy conversion, inspiring further research and potential applications in the field. | Activity | 2025-05-18 | |
| Electrocatalytic Generation of H2 From Wastewater Using Pt decorated TiO2 Catalysts Isabella Smith, Ula Suliman, Dr. Shiva Mohajernia University of Alberta | Activity | 2024-05-09 | Isabella Smith, Ula Suliman, Mohajernia, S. |
| Mesoporous BiVO4 -based Photoelectrode in Water Splitting Photoreactor University of Alberta | Activity | 2024-05-09 | Ali Tavazohi, Mohajernia, S. |
| Minimal Size, Maximum Impact: The Role of Single-Atom Pt in Photocatalytic Hydrogen Production on TiO₂In this presentation, we investigate the use of Pt atoms that are dispersed and anchored as single atoms on nanocrystals, powders, and nanotubes of TiO₂ as cocatalysts for photocatalytic H₂ production. We overview several strategies concerning the trapping and stabilization of SAs on photocatalysts and present some findings related to SA-Pt photocatalysts with superior photocatalytic activity compared to traditional configurations of co-catalysts on semiconductor substrates. Moreover, we demonstrate that only a limited fraction of the overall Pt deposited, when stably trapped as single atoms, supplies nearly all the photocatalytic activity observed for Pt-decorated catalysts. University of Alberta | Activity | 2025-05-18 | Mohajernia, S. |
| Optimizing the Ultra-High Dispersion of Ir on NiO Nanosponge for Enhanced Oxygen Evolution ReactionIn this study, we employ a two-step electrochemical anodization process to fabricate highly porous nickel oxide nanosponges [3]. We then introduce an innovative sonochemical technique that creates defects and achieves ultra-high dispersion of Ir on these porous NiO nanostructures by varying the Ir solution concentration. This single-step sonication process generates a high density of defects within the NiO matrix, stabilizing dispersed Ir sites across the nanostructure [4]. By combining electrochemical anodization with defect engineering via sonication, we achieve efficient entrapment and uniform distribution of Ir at the atomic level. Our results show that defects and the ultra-high dispersion of Ir atoms significantly enhance OER electrocatalytic efficiency. Incorporating Ir into the NiO nanosponge support maximizes the active sites, improving H2O molecule adsorption and its conversion to OH, resulting in more efficient catalysts with improved reaction kinetics for OER. The electrodes are characterized using advanced microscopy techniques, including FESEM, TEM, and HAADF-STEM, alongside spectroscopy methods such as XPS and ToF-SIMS [5]. Linear sweep voltammetry is used to assess the O2 evolution activity of NiO electrodes. These results highlight a significant improvement in the electrocatalytic efficiency of nanostructured NiO electrodes modified with durable and optimized Ir co-catalysts via the sonochemical technique. University of Alberta | Activity | 2025-05-18 | "Nastaran Farahbakhsh", "Majid Shahsanaei", Mohajernia, S., "Sina Hejazi", Manuela S Killian |
| pH-Tuning Strategy for Spontaneous Deposition of Pt Single Atoms on TiO2 NanosheetsIn this work, we demonstrate that Pt SACs can spontaneously deposit on the surface, driven by electrostatic forces; the key is to determine the golden pH and surface potential. We conducted a comprehensive investigation into the influence of the pH of the Pt-containing precursor on the spontaneous adsorption of Pt SACs onto TiO2 nanosheets (TiNSs). We introduced a straightforward pH-dependent and charge-dependent strategy for the solid electrostatic anchoring of Pt SAs on TiNSs. X-ray photoelectron spectroscopy (XPS) and high-angle annular dark-field imaging scanning transmission electron microscopy (HAADF-STEM) were used to evaluate the Pt SA-decorated samples. Photocatalytic hydrogen production activity was assessed under UV (λ = 365 nm) irradiation. Notably, we found that at a pH of 8, slightly below the measured point of zero charge (PZC), a unique mixture of Pt clusters and SAs was deposited on the surface of TiNSs. This unique composition significantly improved hydrogen production, resulting in approximately 3.7 ml of hydrogen generated after 8 hours of UV exposure by only 10 mg of the Pt-decorated TiNSs (with Pt loadings of 0.12 at%), which is about 300 times higher than the undecorated TiNSs. | Activity | 2025-05-18 | Sadegh Pourali, "Kenza Toukabri", "Sina Hejazi", Manuela S Killian |
| Semimetallic Ti-based Bimetallic Oxide: Promising Electrode for Hydrogen Generation University of Alberta | Activity | 2024-04-09 | Ula Suliman, Mohajernia, S. |
| Catalyzing Green Hydrogen Research at the U of A | Activity | 2024-05-09 | |
| Energy Explorers for Science Literacy Week 2023 - WISEST | Activity | 2024-05-09 | Ula Suliman |
| Energy Explorers Teacher Workshop | Activity | 2024-03-11 | Ula Suliman |
| Energy Explorers Teacher Workshop | Activity | 2023-07-04 | |
| Energy Explorers with Junior High Kids | Activity | 2023-11-23 | Ula Suliman |
| NRGMATs Energy Materials Group – Lab Tour Summary for Edmonton's Teachers
In this 25-minute session, participating teachers were introduced to the research activities of the NRGMATs Energy Materials Group, led by Sadegh. The tour focused on the group’s work in developing advanced materials for clean energy technologies, such as photocatalytic hydrogen production and nanostructured semiconductors.
Teachers explored how these research themes connect to high school science curricula—particularly topics like energy conversion, chemical reactions, material properties, and nanoscience. Through live demonstrations and hands-on explanations, the tour highlighted practical ways these concepts could be brought into the classroom to inspire students and show the relevance of science to real-world challenges.
The session provided valuable opportunities for dialogue between researchers and educators, helping bridge the gap between cutting-edge science and classroom teaching.
| Activity | 2024-08-14 | Sadegh Pourali |
| Two visitors from University of Siegen - Germany
Nastaran Farahbakhsh was a visiting PhD student in the NRGMATs group within the Department of Chemical and Materials Engineering at the University of Alberta. Her research focuses on energy materials, particularly nanostructured NiO for energy conversion. Majid is investigating novel nanostructured oxides for energy conversion with Professor Shiva Mohajernia in the NRGMATs group at the University of Alberta. Two visitors from Germany, using the FES-supported equipment, have been actively engaged in these collaborative research efforts.
| Activity | 2024-10-06 | Nastaran Farah Bakhsh, "Majid Shahsanaei" |
| In situ Pt single-atom trapping on TiO2 nanotubes via ultrasonication: a one-pot approach to produce active electrodes for electrocatalytic H2 evolution University of Alberta | Publication | 2024-09-01 | "Sina Hejazi", Sadegh Pourali, "Ali Kosari", "Nastaran Farahbakhsh", Manuela S Killian, Mohajernia, S. |
| Exploring the decoration of nanostructured nickel sub-oxides with single atoms for energy conversion electrocatalysis | Activity | 2024-05-09 | |
