Article
Chemistry, Physical
Chonghan Xia, Xiangrui Meng, Xiuyu Chen, Yang Zhou, Deyu Liu, Yongbo Kuang
Summary: Sn2TiO4 photoanodes exhibit a low onset potential and high photocurrent response, which can effectively enhance the efficiency of solar hydrogen conversion.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Jifang Zhang, Qiyuan Lin, Zhenlei Wang, Haowen Liu, Xuanzhang Li, Yuegang Zhang
Summary: The study proposes that water oxidation on hematite can proceed via mixed reaction paths, contrary to the traditional assumption of a single reaction path. By isolating absorption signals of surface states responsible for water oxidation, the research highlights the significant contribution of direct hole transfer, especially for highly doped hematite. This finding challenges existing experimental techniques that rely on oversimplified models and theories.
Review
Chemistry, Physical
Jifang Zhang, Junyi Cui, Salvador Eslava
Summary: This review discusses efforts to improve water oxidation at photoanodes in the field of photoelectrochemical water splitting, focusing on the use of oxygen evolution catalysts (OECs). The roles of OECs are found to be multifaceted, beyond just catalytic. The review also highlights useful characterization techniques for probing the dynamics of photogenerated holes and proposes design principles for OECs.
ADVANCED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Xiaokang Wan, Yunbo Xu, Xianyun Wang, Xiangjiu Guan, Yanming Fu, Chao Hu, Haowei Hu, Nai Rong
Summary: Plasma enhanced atomic layer deposition and subsequent removal of Al2O3 ultrathin overlayers on bismuth vanadate were utilized to passivate surface states and enhance PEC performance significantly. The modified BiVO4 showed a 73% increase in photocurrent density compared to unmodified BiVO4, demonstrating a novel strategy for surface modification of semiconductors in photoelectrochemical energy conversion.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Hao Wu, Songying Qu, Zhirun Xie, Yun Hau Ng
Summary: This study presents a simple alkaline solution treatment method to enhance the photoelectrochemical water oxidation performance of bismuth vanadate photoanodes. The treatment increases the surface ratio of bismuth to vanadium, resulting in the formation of a bismuth-rich surface and a homojunction within the material. The treated bismuth vanadate photoanode shows significantly improved charge separation efficiency and photon-to-current conversion efficiency.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Marcus Einert, Arslan Waheed, Dominik C. Moritz, Stefan Lauterbach, Anna Kundmann, Sahar Daemi, Helmut Schlaad, Frank E. Osterloh, Jan P. Hofmann
Summary: Metal oxide-based photoelectrodes use nanostructures to increase solid-liquid interface area, reducing charge transport distances and increasing photocurrent. However, the effect of surface order on photocurrent and carrier recombination has not been well studied. Mesoporous CuFe2O4 (CFO) thin film photoanodes with controlled pore order and geometry were prepared. The non-ordered CFO showed the highest photocurrent density for sulfite oxidation but the least for water oxidation, while the ordered CFO showed the best photoelectrochemical water oxidation performance.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Ch. Venkata Reddy, I. Neelakanta Reddy, K. Ravindranadh, K. Raghava Reddy, Jaesool Shim, Bai Cheolho
Summary: The Au-doped BiVO4 nanostructures prepared by ultrasonication technique showed significantly improved performance as a photoanode for energy harvesting in terms of PEC photocurrent density and supercapacitor properties. The dopant enhanced charge carrier density and acted as an electron donor, contributing to the improved performance of the photoanode.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Jing Peng, Guorui Liu, Xianhui Jiao, Hongqiang Xia, Jing Li, Qingxiang Ma, Jun Jin, Feng Li
Summary: A novel electron transport pathway was constructed by growing ZnO/ZnS/ZnIn2S4 heterostructure nanoarrays coaxially, which increased carrier separation efficiency. This new photoanode fulfilled the requirements of favorable band alignment and stability, achieving a stable photocurrent density and may provide a new approach for fabricating efficient photoanodes for PEC water splitting.
Review
Chemistry, Multidisciplinary
Jin-Bo Pan, Sheng Shen, Lang Chen, Chak-Tong Au, Shuang-Feng Yin
Summary: Photoelectrochemical water splitting is a promising solution for solar energy conversion and storage, but the design of efficient photoanodes faces challenges. All known photoanode materials have drawbacks, with core-shell configurations showing potential for improved activity and stability. However, the mechanism for performance improvement still needs further examination.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ken J. Jenewein, Yuanxing Wang, Tianying Liu, Tara McDonald, Matej Zlatar, Nadiia Kulyk, Victoria Benavente Llorente, Attila Kormanyos, Dunwei Wang, Serhiy Cherevko
Summary: Molecular catalysts and photoanodes are promising for solar water splitting, but maintaining their stability is a challenge. This study investigates the relationship between activity and stability of an Fe2O3 photoanode modified with Ir molecular catalysts using mass spectroscopy. The dissolution behavior of the Ir cocatalyst and the impact of electrolyte on the performance are studied. The results highlight the importance of overall photostability and electrolyte engineering in advancing catalysts for solar water splitting.
Article
Energy & Fuels
Annalisa Polo, Maria Vittoria Dozzi, Ivan Grigioni, Charles Lhermitte, Nukorn Plainpan, Luca Moretti, Giulio Cerullo, Kevin Sivula, Elena Selli
Summary: Mo6+ doping enhances the photoelectrochemical performance of BiVO4 photoanodes in water oxidation. The mechanisms behind this improvement are revealed through transient absorption spectroscopy and impedance spectroscopy, showing that Mo6+ ions improve electron transport and surface properties of BiVO4 photoanodes.
Article
Chemistry, Physical
Daniel A. Grave, David S. Ellis, Yifat Piekner, Moritz Koelbach, Hen Dotan, Asaf Kay, Patrick Schnell, Roel van de Krol, Fatwa F. Abdi, Dennis Friedrich, Avner Rothschild
Summary: The article introduces an empirical method to extract the photogeneration yield spectrum xi(λ) through quantum efficiency measurements of ultrathin films. The method can provide insights into the ability of different materials to generate mobile charge carriers through light absorption, and characterize the photoconductivity and photoconversion efficiency.
Article
Chemistry, Multidisciplinary
Junjun Zhang, Cu Dang Van, Kuniharu Takei, Min Hyung Lee
Summary: Arrays of WO3-Si forest hierarchical structures were successfully synthesized by growing WO3 nanorod on the surface of vertically aligned n-Si micropillar arrays. The 3D WO3-Si nanorod forest showed improved photoelectrochemical performances and exhibited higher photocurrent density and a more negative onset potential compared to the WO3 nanorod array on planar Si substrate. Furthermore, the directly grown 3D hierarchical structure demonstrated extraordinary stability for water oxidation with negligible losses of photoactivity for 24 hours. The enhanced photostability was attributed to the formation of O vacancies in WO3 and multiple internal reflection in the 3D hierarchical structure.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Chunlian Hu, Chunjiang Xu, Xiaohu Li, Bonan Li, Xiaoshuo Ma, Jiayu Zhu, Congzhao Dong, Yong Ding
Summary: In this study, a novel molecular cocatalyst, noble-metal-free polyoxometalate (Ni3POM), was incorporated into a typical FeOOH/BiVO4 composite photoanode, greatly enhancing the photoelectrochemical water splitting performance. The Ni3POM/FeOOH/BiVO4 photoanode displayed a photocurrent density of 5.2 mA/cm2 at 1.23 V vs RHE, achieving a 4-fold enhancement compared to the pristine photoanode. The photoanode also exhibited 99% photocurrent density retention after a 1-hour stability test at 1.23 V vs RHE, indicating improved PEC stability. Additionally, a 1.1% ABPE value was achieved at 0.8 V vs RHE.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Tianying Liu, Wei Li, David Z. Wang, Tongtong Luo, Muchun Fei, Dongyoon Shin, Matthias M. Waegele, Dunwei Wang
Summary: Solar water oxidation is a crucial step in artificial photosynthesis, and its success relies on the accumulation of charges at the active site. Little is known about the impact of catalyst density on the reaction rate. This study investigates the interplay between catalyst density and surface hole concentration and reveals the unexpected benefits of low-density catalyst loading in facilitating forward charge transfer.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Matthias H. Richter, Wen-Hui Cheng, Ethan J. Crumlin, Walter S. Drisdell, Harry A. Atwater, Dieter Schmeisser, Nathan S. Lewis, Bruce S. Brunschwig
Summary: The use of electrochemistry, X-ray photoelectron spectroscopy, and resonant X-ray spectroscopy has revealed that while iridium (Ir) and nickel (Ni) electrocatalysts for the oxygen-evolution reaction have similar overpotentials in alkaline media, the interfaces with a-TiO2 exhibit different behaviors. Nickel (Ni) and iridium (Ir) both cause band bending in a-TiO2 for hole conduction, while gold (Au) produces a flat-band interface that limits hole conduction without introducing new band gap states.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Paul Nunez, Miguel Caban-Acevedo, Weilai Yu, Matthias H. Richter, Kathleen Kennedy, Andres Molina Villarino, Bruce S. Brunschwig, Nathan S. Lewis
Summary: Deposition of Pt by electroless or e-beam methods on p-Si leads to different junction characteristics, with the former forming a rectifying junction and the latter forming an ohmic contact. The presence of a thin SiOx layer under the Pt overlayer is observed when Pt is deposited electrolessly. In contrast, e-beam deposition of Pt requires oxidation of the Si surface and leads to the formation of a H-terminated Si surface in addition to the interfacial SiOx layer.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Michelle F. Crook, Christian Laube, Ivan A. Moreno-Hernandez, Axel Kahnt, Stefan Zahn, Justin C. Ondry, Aijia Liu, A. Paul Alivisatos
Summary: By studying the etching of gold nanocrystals in different iron halide solutions, the authors found that the etch rate of gold nanocrystals increased in solutions containing Cl--, Br--, and I--, suggesting that halides act as complexation agents for oxidized gold species. Additionally, data indicate that an oxidized Fe species may be the active oxidant, while halides modulate the etch rate by tuning the reduction potential of gold nanocrystals.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Ivan A. Moreno-Hernandez, Michelle F. Crook, Justin C. Ondry, A. Paul Alivisatos
Summary: Researchers developed a new method that utilizes redox species to scavenge radicals and control electrochemical potential in situ, enabling precise control over liquid environment for near-atomic resolution observation of electrochemical structural dynamics. This approach shows promise for generalization across various chemical systems and provides unprecedented detail for the study of complex nanoscale dynamics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Nanoscience & Nanotechnology
Ellen Yan, Renata Balgley, Maureen B. Morla, Soonho Kwon, Charles B. Musgrave, Bruce S. Brunschwig, William A. Goddard, Nathan S. Lewis
Summary: Reductant-activated functionalization enhances the methylation of ceMoS2 and ceWS2 by introducing excess negative charge for nucleophilic attack reaction. The coverage of ceWS2 increases from 25% to 52% with the presence of reductant, while the methyl coverage on ceWS2 is about 20% lower than ceMoS2 at every potential. Density functional theory calculations show that methylation is thermodynamically and kinetically more favorable on 1T'-MoS2 than 1T'-WS2 due to the presence of more negative charge on 1T'-MoS2. However, this effect is moderated when the reactions are compared at constant charge, emphasizing the importance of comparing reactivity at nominally identical electrode potentials.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Harold J. Fu, Pakpoom Buabthong, Zachary Philip Ifkovits, Weilai Yu, Bruce S. Brunschwig, Nathan S. Lewis
Summary: Research shows that Ni and NiOx-based thin films can catalyze the oxidation of Si in the presence of oxygen, extending the lifespan of Si/Ni electrodes. In contrast, electrodes without these films are more prone to corrosion. Operating in alkaline conditions, lowering the electrolyte pH can increase the durability of the photoanode, but may reduce the efficiency of water oxidation.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Chemistry, Physical
Pakpoom Buabthong, Jake M. Evans, Katherine Z. Rinaldi, Kathleen M. Kennedy, Harold J. Fu, Zachary P. Ifkovits, Tai-Jung Kuo, Bruce S. Brunschwig, Nathan S. Lewis
Summary: The study utilized microisland structures to spatially isolate defects and investigated the rate and distribution of pinhole formation during electrochemical operation, protected by thin amorphous titanium dioxide films. It was found that a limited number of defects in the a-TiO2 layer developed into new microscopic pinholes within the first 20 h, with a slow film dissolution rate. The results suggest that intrinsic film dissolution was not the primary mode of pinhole formation during the initial 20 h of operation.
ACS ENERGY LETTERS
(2021)
Article
Multidisciplinary Sciences
Chang Yan, Dana Byrne, Justin C. Ondry, Axel Kahnt, Ivan A. Moreno-Hernandez, Gaurav A. Kamat, Zi-Jie Liu, Christian Laube, Michelle F. Crook, Ye Zhang, Peter Ercius, A. Paul Alivisatos
Summary: The size and shape of semiconductor nanocrystals determine their optical and electronic properties. Liquid cell transmission electron microscopy (LCTEM) is a useful tool for directly observing nanoscale chemical changes and guiding the synthesis of nanostructures with desired functions. This study reveals that the reactivity of specific surfaces in liquid environments plays a crucial role in governing the nanoscale shape transformations of semiconductor nanocrystals.
Article
Chemistry, Multidisciplinary
Michelle F. Crook, Ivan A. Moreno-Hernandez, Justin C. Ondry, Jim Ciston, Karen C. Bustillo, Alfred Vargas, A. Paul Alivisatos
Summary: Graphene liquid cell transmission electron microscopy is a powerful technique for visualizing nanoscale dynamics. In this study, electron energy loss spectroscopy (EELS) was used to evaluate the concentration and chemistry of a model encapsulated solution in graphene liquid cells. The results showed that the encapsulated solution is highly concentrated, which affects the oxidation kinetics of Ce3+. Moreover, the rate constants and g-values of certain molecular species were found to be different in highly concentrated environments. This study provides new insights into previous research and opens up opportunities for studying systems in highly concentrated solutions at high resolution.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Ivan A. Moreno-Hernandez, Michelle F. Crook, Vida Jamali, A. Paul Alivisatos
Summary: This article discusses recent advancements in understanding electron beam-driven chemical reactions in liquid-phase transmission electron microscopy (LPTEM) and the development of improved experimental control strategies. Additionally, the use of machine learning algorithms to analyze LPTEM data has accelerated the interpretation process. These efforts are expected to contribute to further advancements in the application of LPTEM in materials science, chemistry, biology, and nanotechnology.
Article
Chemistry, Multidisciplinary
Weilai Yu, Matthias H. Richter, Pakpoom Buabthong, Ivan A. Moreno-Hernandez, Carlos G. Read, Ethan Simonoff, Bruce S. Brunschwig, Nathan S. Lewis
Summary: This study evaluated the stability of p-InP photocathodes for the hydrogen-evolution reaction, finding that electrodeposition of Pt can stabilize the illuminated p-InP photocathodes and inhibit the corrosion pathway, maintaining a stable current density under simulated sunlight. In acidic media, the surface of p-InP/Pt electrodes became gradually phosphorous-rich over time, while in alkaline electrolyte, the formation of an InOx layer on the electrode surface led to a significant degradation in the J-E characteristics.
ENERGY & ENVIRONMENTAL SCIENCE
(2021)
Article
Chemistry, Physical
Weilai Yu, Matthias H. Richter, Ethan Simonoff, Bruce S. Brunschwig, Nathan S. Lewis
Summary: The long-term stability of p-GaAs photocathodes for the hydrogen-evolution reaction in different acidic and alkaline electrolytes was investigated, with coated electrodes showing reduced adverse interfacial reactions in certain conditions.
JOURNAL OF MATERIALS CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
Xingzhi Wang, Jie Li, Hyun Dong Ha, Jakob C. Dahl, Justin C. Ondry, Ivan Moreno-Hernandez, Teresa Head-Gordon, A. Paul Alivisatos
Summary: The AutoDetect-mNP algorithm is an unsupervised method that can automatically extract morphological information of convex mNPs from TEM images, providing objectivity and reliability while reducing human effort. It can serve as a generalizable measure for studying the morphology distributions of various mNP syntheses and will aid in future developments of high-throughput characterization and time-resolved TEM studies.
Article
Chemistry, Physical
Samantha I. Johnson, James D. Blakemore, Bruce S. Brunschwig, Nathan S. Lewis, Harry B. Gray, William A. Goddard, Petter Persson
Summary: The attachment of 2,2'-bipyrdine (bpy) moieties to planar silicon surfaces was investigated, revealing that adventitious chlorine atoms in the organic linker backbone caused instability at very negative potentials. Computational studies showed that structures with fluorine substituents were more stable, while fully non-halogenated structures exhibited the highest stability. Immobilizing a hydrogen-evolving molecular catalyst on a silicon cluster showed that reductively stable linkers enabled robust attachment of catalysts with behavior similar to that in homogeneous solution.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
