Article
Chemistry, Physical
Jacob A. Spies, John R. Swierk, H. Ray Kelly, Matt D. Capobianco, Kevin P. Regan, Victor S. Batista, Gary W. Brudvig, Charles A. Schmuttenmaer
Summary: The composition of SnxTi1-xO2 can be adjusted to tune the conduction band, affecting the driving force for forward IET and the electronic states involved. Tuning of IET can be achieved by modulating the absorption spectrum of the adsorbed dye and altering electron acceptor states in the conduction band. Incorporation of Ti d-character in the conduction band is crucial in promoting ultrafast electron injection, as shown by periodic DFT calculations.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Qian Guo, Qi Zhao, Rachel Crespo-Otero, Devis Di Tommaso, Junwang Tang, Stoichko D. Dimitrov, Maria-Magdalena Titirici, Xuanhua Li, Ana Belen Jorge Sobrido
Summary: Single-atom catalysts (SACs) on hematite photo-anodes act as true catalysts by trapping holes from hematite and providing active sites for water oxidation. Spectroscopic experiments and computer simulations demonstrate reduced hole number and shortened hole lifetime in the presence of SACs. Density functional theory calculations reveal that SACs display a lower onset potential and introduce a mid-gap of 4d state for fast hole transfer and depletion. These findings provide new insights into solar water oxidation and the role of SACs in enhancing semiconductor catalytic performance in photo-assisted reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Andreas Ringleb, Raffael Ruess, Nico Hofeditz, Wolfram Heimbrodt, Tsukasa Yoshida, Derck Schlettwein
Summary: The research found that V-OC of DSSCs can be significantly increased by Mg-doping, and the Mg concentration in MZO affects the transport and recombination of electrons in MZO, which in turn influences the performance of the cells. Nanoparticles with a pure ZnO core and an MZO shell structure can help reduce the impact of increased transport resistance in MZO and utilize the improved V-OC.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Zhenzhen Zhang, Xiaojuan Huang, Beibei Zhang, Yingpu Bi
Summary: In this study, it is reported that a combination of phosphorus-oxygen bonded catalysts and BiVO4 photoanodes can significantly enhance the photoelectrochemical water oxidation activity and stability. The experimental and analysis results provide insights into the electron density redistribution and electronic coupling between the catalysts and photoanodes. This work offers a new approach for designing efficient photoanodes for solar water splitting applications.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Review
Chemistry, Multidisciplinary
Degao Wang, Qing Huang, Weiqun Shi, Wei You, Thomas J. Meyer
Summary: Atomic layer deposition (ALD) is extensively used in modifying semiconductor surfaces, particularly in the preparation of solar fuels by creating core/shell structures, stabilizing surface-bound chromophores and catalysts, as well as stabilizing electrodes for water oxidation and photocathodes for H-2 or CO2 reduction in DSPECs applications.
TRENDS IN CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Rui-Ting Gao, Lijia Liu, Yanbo Li, Yang Yang, Jinlu He, Xianhu Liu, Xueyuan Zhang, Lei Wang, Limin Wu
Summary: By dispersing Ru and P diatomic sites onto hematite, an efficient photoelectrode was constructed using the concept of correlated single-atom engineering, resulting in improved charge carrier transportation dynamics and increased efficiency for photoelectrochemical water splitting.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Energy & Fuels
Tharmakularasa Rajaramanan, Fatemeh Heidari Gourji, Dhayalan Velauthapillai, Punniamoorthy Ravirajan, Meena Senthilnanthanan
Summary: This study reports a facile approach to fabricate nitrogen-doped TiO2 (N-doped TiO2) photoanode for DSSC application. The synthesized nanoparticles were extensively characterized by XRD, XPS, EDX, SEM, and TEM techniques. The photoanode doped with 20 mu L of NH4OH (20N-TiO2) exhibited the highest power conversion efficiency (PCE) of about 6.16%.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2023)
Article
Chemistry, Physical
Amin Reza Zolghadr, Niloufar Azari, Maryam Heydari Dokoohaki
Summary: The study investigated the effects of electrolyte solutions containing acetonitrile solvent and various salts on the performance of dye-sensitized solar cells (DSSCs). Experimental results showed that the DSSC exhibited high performance when a mixture of potassium iodide (KI) and 1-ethyl-3-methylimidazolium iodide ionic liquid (Emim-I) was used. Additionally, molecular dynamics simulations were conducted to study the interface of solid/liquid electrolytes, revealing the significant influence of cations on the density distribution of anions at the interface.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Nanoscience & Nanotechnology
Zhongyuan Zhou, Yanmei Liang, Xiu-Shuang Xing, Kunhao Zhang, Yongsheng Niu, Liguo Yang, Fang Wang, Zhanhu Guo, Haixiang Song, Shaolong Wu
Summary: Photoelectrochemical water splitting (PEC-WS) is an environmentally friendly technology for hydrogen generation. Hematite (α-Fe2O3) photoanodes have been widely studied in PEC-WS due to their high absorption coefficient and suitable bandgap, but they suffer from carrier recombination and poor oxygen evolution kinetics. By coupling the electron transport layer of titanium dioxide (TiO2) and the surface catalyst of cobalt-phosphate (Co-Pi), α-Fe2O3 photoanodes exhibit excellent long-term stability, significantly enhanced photocurrent, and a lower onset potential. This work provides an advanced strategy for surface and interface engineering to improve carrier extraction and hydrogen production efficiency in the field of photoelectric conversion.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Palyam Subramanyam, Bhagatram Meena, Duvvuri Suryakala, Challapalli Subrahmanyam
Summary: The study demonstrates that incorporating Bi2Se3 nanoflowers into TiO2 electrode significantly enhances the PEC performance, leading to an increase in hydrogen production by an order of magnitude. The binary TiO2/Bi2Se3 nanocomposite electrode exhibits high photocurrent density and hydrogen conversion efficiency.
ACS APPLIED NANO MATERIALS
(2021)
Review
Chemistry, Multidisciplinary
Xiaoyan Zhang, Shengqi Zhang, Xiaoli Cui, Wei Zhou, Weimin Cao, Danhong Cheng, Yi Sun
Summary: This review focuses on the application of TiO2-based photoanodes in PEC water splitting. TiO2 exhibits high PEC water splitting performance, but its performance is hindered by certain disadvantages. The review highlights the mechanisms and key factors for achieving high solar-to-hydrogen conversion efficiency, as well as controllable synthesis and modification strategies. The future trends for TiO2-based photoanodes in PEC water splitting are also discussed.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Varishetty Madhu Mohan, Kenji Murakam, Madhavi Jonnalagadda, V. R. Machavaram
Summary: Pure TiO2 and surface-modified TiO2 films were developed using spray pyrolysis technique, with similar crystal structure and optical absorption properties. However, the addition of ZnO layer in SMT films increased impedance and hindered reverse electron transmission. Thus, the efficiency of DSSCs improved from 8.25% to 9.3%.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Ceramics
Nicola Sangiorgi, Riccardo Bendoni, Alex Sangiorgi, Lucrezia Aversa, Roberta Tatti, Roberto Verucchi, Alessio Adamiano, Monica Sandri, Anna Tampieri, Alessandra Sanson
Summary: The study investigates the use of titanium-doped hydroxyapatite (TiHA) as a photoanode material for Dye-Sensitized Solar Cells, with characterization of TiHA powders with varying titanium content. Results show high compatibility of TiHA with ruthenium-based dye molecules, and the highest efficiency was achieved with 15 wt% titanium-doped TiHA.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Xinrui Xie, Yuyan Zhang, Yutong Ren, Lifei He, Yi Yuan, Jing Zhang, Peng Wang
Summary: Overcoming excited-state quenching and interfacial charge recombination is crucial for achieving efficient and durable dye-sensitized solar cells (DSSCs). Cografting a wide-energy-gap adsorbent and a low-energy-gap photosensitizer on a mesoporous titania film improves electron injection, hole injection, and interfacial charge recombination kinetics, leading to increased efficiency.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Review
Chemistry, Multidisciplinary
Ana Belen Munoz-Garcia, Iacopo Benesperi, Gerrit Boschloo, Javier J. Concepcion, Jared H. Delcamp, Elizabeth A. Gibson, Gerald J. Meyer, Michele Pavone, Henrik Pettersson, Anders Hagfeldt, Marina Freitag
Summary: Dye-sensitized solar cells (DSCs) and dye-sensitized photoelectrochemical cells (DSPECs) have seen a revival in recent years as they offer unique properties such as low cost, non-toxic materials, colorfulness, transparency, and efficiency in low light conditions. This review covers advancements in DSC technology over the past decade, including theoretical studies, characterization techniques, materials, applications, and commercialization efforts by various companies.
CHEMICAL SOCIETY REVIEWS
(2021)
Article
Nanoscience & Nanotechnology
Pratibha Mahale, Byeongdu Lee, Hiu Yan Cheng, Mo Segad, Thomas E. Mallouk
Summary: Colloidal crystals made from sub-100 nm silica nanoparticles have been investigated for their structures and their effects on germanium replicas using scanning electron microscopy and small angle X-ray scattering in this study. The results show that the size of particles plays a crucial role in determining the structure and crystal domain size of colloidal crystal films.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Amy S. Metlay, Brandon Chyi, Yein Yoon, Ryszard J. Wycisk, Peter N. Pintauro, Thomas E. Mallouk
Summary: Aqueous acid-base redox flow batteries utilize pH gradient for increased energy storage capacity. By employing a three-chamber cell design and inserting a cation exchange membrane between the bipolar membrane, stability and cycle life of the battery can be improved. This design also allows the use of highly positive and soluble redox couples.
ACS ENERGY LETTERS
(2022)
Article
Multidisciplinary Sciences
Shunta Nishioka, Koya Hojo, Langqiu Xiao, Tianyue Gao, Yugo Miseki, Shuhei Yasuda, Toshiyuki Yokoi, Kazuhiro Sayama, Thomas E. Mallouk, Kazuhiko Maeda
Summary: Researchers have improved the energy conversion efficiency of solar-driven water splitting for hydrogen production by modifying metal oxides. The use of the optimized photocatalyst achieved the highest STH and apparent quantum yield.
Article
Nanoscience & Nanotechnology
Tianyue Gao, Jeffrey M. McNeill, Vincent A. Oliver, Langqiu Xiao, Thomas E. Mallouk
Summary: Self-powered, biocompatible pumps in the nanometer to micron length scale have the potential to enable technology in several fields. Chemically powered, catalytic micropumps have been developed but are not able to function well in biocompatible environments. In contrast, enzymatically powered catalytic pumps offer good biocompatibility, selectivity, and scalability, but their performance at length scales below a few millimeters has not been well tested.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Inorganic & Nuclear
Jarrett D. Dillenburger, Minh An T. Nguyen, Pengtao Xu, Jeffrey R. Shallenberger, Thomas E. Mallouk
Summary: Basal plane-functionalized NbS2 nanosheets were obtained using in situ photolysis to generate the coordinatively unsaturated organometallic fragment, which bonded to electron-rich sulfur atoms on the surface under UV irradiation. The reactivity difference with MoS2 nanosheets was attributed to the stronger bonding with metallic NbS2 than with semiconducting MoS2, as supported by electronic structure calculations and characterization using XPS, FTIR, and PXRD.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Ritesh Uppuluri, Sooyeon Hwang, Sharad Maheshwari, Pengwei Zhao, Jennifer L. Gray, Alyssa S. Rosas, Hemant P. Yennawar, Xiaobin Fan, Michael J. Janik, Thomas E. Mallouk
Summary: This study investigates the stability of dinuclear rhodium and iridium clusters adsorbed onto layered titanate and niobate supports. The results show that both systems maintain their nuclearity, with rhodium and iridium clusters dispersed without aggregation. Further analysis reveals the stability and adsorption mode of rhodium clusters on nanosheets.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jeffrey M. McNeill, Yun Chang Choi, Yi-Yu Cai, Jiacen Guo, Francois Nadal, Cherie R. Kagan, Thomas E. Mallouk
Summary: This study reports the assembly and phase separation of microspinners powered by sound waves. A phase diagram is constructed by studying the interactions between spinners at different densities, showing gaseous dimer pairing, collective rotation, multiphase separation, and jamming. The observations are consistent with recent theoretical predictions and provide an exciting experimental window for the study of colloidal active matter and microrobotic systems.
Article
Chemistry, Inorganic & Nuclear
Walter D. Johnsen, Mawuli Deegbey, David C. Grills, Dmitry E. Polyansky, Karen I. Goldberg, Elena Jakubikova, Thomas E. Mallouk
Summary: A series of dinuclear molecular copper complexes were prepared to model the binding and Lewis acid stabilization of CO in heterogeneous copper CO2 reduction electrocatalysts. Experimental studies and electronic structure calculations suggest that the key kinetic barrier for CO binding may be a sigma-interaction between Cu-I and the incoming CO ligand. Modifying the ligand backbone or adding Lewis acids can change the thermodynamics and kinetics for CO coordination, allowing access to different reaction zones.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Sa Suo, Colton Sheehan, Fengyi Zhao, Langqiu Xiao, Zihao Xu, Jinhui Meng, Thomas E. Mallouk, Tianquan Lian
Summary: Metal-insulator-semiconductor (MIS) junctions are considered a promising architecture for water splitting and CO2 reduction reactions. However, it is challenging to directly measure the photovoltage at metal sites in MIS photoelectrodes. In this study, a new in situ spectroscopic approach using surface-enhanced Raman spectroscopy is developed to probe the quasi-Fermi level of metal catalyst sites in heterogeneous MIS photoelectrodes. The approach is successfully demonstrated on a CO2 reduction photocathode, showing selective probe of the photovoltage generated at the Si/SiO x /Ag junctions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Nanoscience & Nanotechnology
Georgia Potsi, Yu-Han Joseph Tsai, Austin Reese, Dasol Yoon, Jeremy L. Hitt, Antonios Kouloumpis, Jin Suntivich, David A. Muller, Thomas E. Mallouk, Emmanuel P. Giannelis
Summary: The structural characteristics of supports greatly influence the deposition mechanism of Pt nanoparticles and their electrochemical performance in fuel cells. This study used high surface area hierarchical porous carbons (HPCs) as model supports to investigate the deposition mechanism of Pt nanoparticles. Despite similar chemical composition and surface area, the size of deposited Pt nanoparticles was inversely proportional to the mesopore size of the system. Additionally, increasing the size of catalyst particles can enhance the specific activity of the oxygen reduction reaction. Moreover, the overall performance of alkaline fuel cells can be improved by increasing the electronic conductivity of the carbon support using highly conductive graphene sheets.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Jarrett D. Dillenburger, Leanna Schulte, Pratibha Mahale, Mohammed Suleiman, Thomas E. Mallouk
Summary: In this study, the structure-property relationships of different compositions of MgAl layered double hydroxides (LDHs) intercalated with various anions were explored. It was found that the intercalated anions had a significant impact on interlayer spacing, OH- conductivity, and interlayer water retention. LDHs intercalated with ClO4(-) or NO3(-) anions showed sustained enhancement of in-plane OH- conductivity at intermediate temperatures, despite decreasing relative humidity. The findings suggest a design principle for robust LDH-based anion-exchange membranes for electrochemical applications.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Luis R. De Jesus Baez, Alyssa S. Rosas, Pratibha Mahale, Thomas E. Mallouk
Summary: MXenes are materials with interesting electrochemical, electronic, and surface chemical properties. The method used to etch the parent MAX compound strongly affects the nature of the terminal groups on the MXene sheets. In this study, low concentration of HF and a chelating agent were used to selectively etch Ti3AlC2, retaining the carbide bonding in the MXene layers and improving its stability in aqueous suspensions.
Article
Energy & Fuels
Haruka Yamamoto, Shunta Nishioka, Langqiu Xiao, Yugo Miseki, Kazuhiro Sayama, Thomas E. Mallouk, Kazuhiko Maeda
Summary: Pt-intercalated calcium niobate nanosheets sensitized by a Ru(II) complex dye and modified with anionic polymers were investigated for their photocatalytic activity in hydrogen production. The results showed that polymer modification had a positive impact on the activity, especially under high light intensity conditions. In Z-scheme overall water splitting, both PSS and PMA exhibited similar energy conversion efficiencies, but PMA outperformed PSS at different NaI concentrations.
Article
Chemistry, Multidisciplinary
Zhifei Yan, Michael Colletta, Akshay Venkatesh, Yao Yang, Jeremy L. Hitt, Jeffrey M. McNeill, Lena F. Kourkoutis, Hector D. Abruna, Thomas E. Mallouk
Summary: This study investigates the performance of the cathode in alkaline fuel cells using cryo-electron microscopy, electrochemistry, and numerical modeling. The results suggest that the conventional electrode architecture would work more efficiently with more permeable ionomers, while the fiber architecture effectively manages oxygen and ion transport but is limited by catalyst activity.
CELL REPORTS PHYSICAL SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Pratibha Mahale, Byeongdu Lee, Hiu Yan Cheng, Mo Segad, Thomas E. Mallouk
Summary: This study investigated the structures of colloidal crystals made from sub-100 nm silica nanoparticles and revealed that the structure depends on particle size. The structure of these materials remains intact under high temperature and pressure, with factors like shear force during deposition and dispersity of silica nanoparticles influencing the size of crystal domains in the films.
ACS APPLIED MATERIALS & INTERFACES
(2022)