Chemistry Commons^™

Experimental And Computational Study On Magnetic Nanowires Of Layered Titanates, Caleb Layne Heath

Graduate Theses and Dissertations

The intricate nanostructures of layered titanates are unique among nanomaterials due to their easy and inexpensive syntheses. These nanomaterials have been proven valuable for use in industries as varied as energy, water treatment, and healthcare, and can be produced at industrial scales using already existent equipment. They have complex morphology, and surface structure well suited to chemical modification and doping. However, there is a longstanding debate on their lattice structure after the doping. There is a long-unmet need to understand, using both experimental and simulation methods, how dopants alter the clay-like layered crystal structure and associated physical and chemical properties. …

In Situ/Operando Visualization Of Electrode Processes In Lithium-Sulfur Batteries: A Review, Shuang-Yan Lang, Xin-Cheng Hu, Rui Wen, Li-Jun Wan

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries have been regarded as one of the most promising candidates for the next-generation energy storage devices. Fundamental understanding of the structure and evolution processes at electrode-electrolyte interfaces is essential to the further development. In this review, we summarize recent advances in the interfacial observations by means of various in situ/operando visualization techniques, including scanning probe microscopy (SPM), electron microscopy (EM), X-ray microscopy (XRM) and optical microscopy (OM). The real-time investigation provides important evidence for the morphology and component changes including S/Li₂S transformation, polysulfide dissolution on cathodes and Li/solid electrolyte interphase (SEI) evolution on anodes, which …

Application Of Nanomaterials In The Detection Of Volatile Organic Compounds In Exhaled Breath For Cancer Diagnosis, Wan-Qiao Bai, Xue-Zhi Qiao, Tie Wang

Journal of Electrochemistry

Volatile organic compounds (VOCs) generated in human body can reflect one’s health state, and numerous diseases are identified by some VOCs biomarkers. More recently, analyses of VOCs biomarkers from exhaled breath have turned into a research frontier worldwide because it offers a noninvasive way for diseases diagnosis. Various kinds of nanomaterials are used to enhance the performance of sensing techniques, and play an essential role in miniaturization detection. In this review, several kinds of nanomaterials (metallic, metal oxide, carbon-based, composites and MOFs-based materials) used in various VOCs detection methods, especially in VOCs sensors are summarized. Learning from the successful utilization …

Surface-Enhanced Infrared Absorption Spectroscopy- Surface Sensitive In Situ Label-Free Spectroelectrochemistry, Lie Wu, Jian-Long Sun, Xiu-E Jiang

Journal of Electrochemistry

Surface-enhanced infrared absorption spectroscopy (SEIRAS), especially in attenuated total reflectance (ATR) mode, taking advantages of surface-enhancement and near-field optical effect of enhancing substrate, is a ultra-sensitive infrared spectroscopy, which could achieve surface-selected detection at a sub-monolayer level. Since the enhancing substrate could simultaneously serve as a working electrode, ATR-SEIRAS is a readily surface-sensitive in situ label-free spectroelectrochemistry technique. With the advantages of small influence from metal species on enhancement effect, good potential reversibility of spectra, simple surface selection rule and sensitivity to polar molecules, ATR-SEIRAS has been widely applied in the fields of orientation analysis and species identification of interfacial …

A Facile Strategy For Two-Step Fabrication Of Gold Nanoelectrode For In Vivo Dopamine Detection, Li-Hao Guan, Chao Wang, Wang Zhang, Yu-Lu Cai, Kai Li, Yu-Qing Lin

Journal of Electrochemistry

In vivo monitoring neurochemicals with microelectrode is invasive and the damage to brain tissue may inevitably cause disturbance signals physiologically to the measurement. It is of great importance to reduce the electrode size and to decrease the damage. This study demonstrates a novel nanoelectrode preparation methodology for in vivo monitoring dopamine (DA) fluctuation in the living brain of rats with high dependability. The fabrication process of the gold nanoelectrode involving a few minutes consists of only two steps: 1) growing gold nanoseeds on surface of tip of glassy capillary by ion sputtering; 2) wet depositing a continuous conductive gold film …

High-Efficiency Nitrite Sensor Based On Cop Nanowire Array, Fu-Ling Zhou, Xiao-Li Xiong, Xu-Ping Sun

Journal of Electrochemistry

Nitrite has a negative impact on the environment and human health. The long-term consumption of nitrite-containing foods has a carcinogenic risk. Therefore, the analysis and detection of nitrite are important. It is of great significance to develop high-efficiency electrocatalysts to achieve high sensitivity and selectivity for nitrite detection. The cobalt phosphide nano-array (CoP/TM) was obtained by hydrothermal and low-temperature phosphating. The electrochemical test results show that the constructed CoP/TM was a highly efficient electrochemical reduction nitrite catalyst with the excellent sensing performance and response time less than 3 s, as well as the linear detection range of 1.0 μmol·L^{-1 …}

Graphene-Like Secondary-Laser-Etched Polyimide Film Decorated With CuXO Nanocomposites: A Novel Electrode Substrate For Non-Enzymatic Glucose Sensors, Wan-Lin Dai, Zhi-Wei Lu, Jian-Shan Ye

Journal of Electrochemistry

In this work, a novel electrode substrate with graphene-like surface and Cu_xO nanocomposites derived from secondary-laser-etched polyimide (SLEPI) film was synthesized and applied in non-enzymatic glucose detection for the first time. Characterizations indicate that the as-prepared SLEPI/Cu_xO film electrode (SLEPI/Cu_xO-FE) possessed huge surface area, plentiful active sites and excellent electrocatalytic performance. The obtained sensor exhibited the high sensitivity and selectivity for glucose determination with a linear range of 0.05 mmol·L^-1 to 3 mmol·L^-1 and a detection limit of 1.72 μmol·L^-1 (S/N=3), which provides a simple, flexible and low-cost electrochemical sensor for …

Recent Developments In Surface/Interface Modulation And Structure-Performance Relationship Of Cathode Catalysts For Li-Air Batteries, Rui Gao, Jun-Kai Wang, Zhong-Bo Hu, Xiang-Feng Liu

Journal of Electrochemistry

Lithium-air battery has been considered to be one of the most promising secondary battery systems because of its high energy density. However, the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the cathode, and the high overpotential, poor cycle stability and low rate capacity have severely blocked the development and application of Li-air battery. One of the effective strategies to alleviate these issues is to develop cathode catalysts for Li-air batteries. The design and development of bifunctional cathode catalysts with high activity and efficiency on both ORR and OER is highly desired for Li-air …

Mass Spectrometry Analysis Of Contaminants Of Emerging Concern: Nanoparticles, Algal Toxins, And Cyanotoxins In Natural Waters And Their Potential Health Impacts, Ariel R. Donovan

Doctoral Dissertations

“The analysis of contaminants of emerging concern is critical to protecting environmental health. In the presented dissertation, two groups of contaminants of emerging concern were assessed using mass spectrometry methods: nanoparticles and algal and cyanotoxins.

Analysis of metal oxide nanoparticles in environmental matrices has been a challenging issue, as most traditional methods require complicated sample preparation methods or that can alter or destroy the nanoparticles in the system. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) methods were used to detect metal oxide nanoparticles in surface waters and their removal through drinking water treatment simulations while retaining all information regarding …

Constructions Of Noble Metal Nanocrystals With Specific Crystal Facets And High Surface Area, Qiao-Li Chen, Hui-Qi Li, Ya-Qi Jiang, Zhao-Xiong Xie

Journal of Electrochemistry

Noble metal nanocrystals (NCs) have widespread applications in catalysis. Their catalytic performances are strongly related to the surface structures while the atomic utilization efficiency of noble metal is considerably correlated with the surface area. Thus, advantages of both specific surface structure and large surface area are highly required to show off simultaneously so as to optimize the catalytic performance and decrease the usage of noble metal. However, it seems that the two advantages are incompatible with each other in one NC since it is difficult for small NCs to keep their specific facets, while NCs with specific surface structure usually …

The Pilot Application Of Electrochemical Impedance Spectroscopy On Dynamic Proton Exchange Membrane Fuel Cell, Jian-Wei Guo, Jian-Long Wang

Journal of Electrochemistry

By analyzing Electrochemical Impedance Spectroscopy (EIS) in applications of dynamic proton exchange membrane fuel cell (PEMFC), bottlenecks which restrict EIS tool development have been pointed out in this paper. Though the high-frequency resistance in EIS is largely accepted as cell inner-resistance, this can only be applied for cell with low current. The low-frequency resistance is difficult to be realized due to its relation with mass transfer. Furthermore, the improved Randles equivalent circuits are built up preliminarily, thus, penetrating into studies for mass transfer reaction, cell operation/degeneration, and high temperature fuel cell. Inspiringly, EIS is becoming an analyzing tool for stack …

Fe-N Doped Hollow Carbon Nanospheres Linked By Carbon Nanotubes For Oxygen Reduction Reaction, Ya-Lin Zhang, Chi Chen, Liang-Liang Zou, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

The development of non-precious metal catalysts for oxygen reduction reaction (ORR) is essential for large-scale application of proton exchange membrane fuel cells. Herein, we present the in situ formed Fe-N doped hollow carbon nanospheres linked by carbon nanotubes composite, synthesized by using ZIF-8 as sacrificed template to form polydopamine (PDA) hollow nanospheres, followed by complexing with FeCl₃, high temperature heat-treatment and NH₃-etching. ZIF-8 was gradually decomposed simultaneously with PDA coating due to the loss of Zn²⁺ grabbed by PDA. NH3 etching resulted in the improved surface area, while the reducibility of NH₃ resulted in …

Facile Synthesis Of Pt-Cu Alloy Nanodendrites As High-Performance Electrocatalysts For Oxygen Reduction Reaction, Liu-Xuan Luo, Guang-Hua Wei, Shui-Yun Shen, Feng-Juan Zhu, Chang-Chun Ke, Xiao-Hui Yan, Jun-Liang Zhang

Journal of Electrochemistry

Structures and compositions have significant effects on the catalytic properties of nanomaterials. Herein, a facile etching-based method was employed to synthesize Pt-Cu nanodendrites (NDs) with uniform and homogeneous alloy structures for enhancing oxygen reduction reaction (ORR). The formation of dendritic morphology was ascribed to the etching effect caused by the oxidative etchants of the Br^-/O₂ pair. The atomic ratio of Pt/Cu in Pt-Cu NDs could be easily tuned by altering the ratio of the Pt/Cu precursors, without deteriorating the dendritic morphology. The most active carbon-supported Pt₁Cu₁ NDs (Pt₁Cu₁ NDs/C) exhibited the …

Caging Porous Co-N-C Nanocomposites In 3d Graphene As Active And Aggregation-Resistant Electrocatalyst For Oxygen Reduction Reaction, Lu-Yang Xiu, Meng-Zhou Yu, Peng-Ju Yang, Zhi-Yu Wang, Jie-Shan Qiu

Journal of Electrochemistry

Oxygen reduction reaction (ORR) is the cornerstone reaction of many renewable energy technologies such as fuel cells and rechargeable metal-air batteries. The Pt-based electrocatalysts exhibit the highest activity toward ORR, but their large implementation is greatly prohibiting by unaffordable cost and inferior durability. During electrode manufacturing and electrochemical reaction, severe aggregation of catalyst nanoparticles induced by size effect further limits the operational performance of electrocatalysts. We report a new strategy for fabrication of active and aggregation-resistant ORR electrocatalyst by caging metal-organic frameworks derived Co-N-C nanocomposites in permeable and porous 3D graphene cages via sprayed drying the mixed colloids of ZIF-67 …

Palladium Adatoms On Gold Nanoparticles As Electrocatalysts For Ethanol Electro-Oxidation In Alkaline Solutions, Hui-Mei Chen, Shang-Qian Zhu, Jia-Le Huang, Min-Hua Shao

Journal of Electrochemistry

Palladium (Pd) is a good catalyst for ethanol electro-oxidation in alkaline solutions. The activity of Pd is further improved in this study by modifying the gold (Au) nanoparticles with Pd adatoms using a simple spontaneous deposition process. The Pd overlayer on the Au core (Au@Pd) is un-uniform with some Au atoms exposed to the electrolyte. The activity of Au@Pd/C toward ethanol oxidation reaction (EOR) is much higher than that of Pd/C in an alkaline solution. The peak current density of Au@Pd/C is 4.6 times higher than that of Pd/C with a 100 mV lower onset potential. The enhanced activity may …

Micro-Flow Nanocatalysis: Synergic Effect Of Tfoh@Spions And Micro-Flow Technology As An Efficient And Robust Catalytic System For The Synthesis Of Plasticizers, Maryam Tashi, Behnaz Shafiee, Yoshie Sakamaki, Ji-Yun Hu, Zachary Heidrick, Ahmad R. Khosropour, M. Hassan Beyzavi

Chemistry & Biochemistry Faculty Publications and Presentations

The combination of continuous flow technology with immobilizing of only 0.13 mol% of triflic acid (TfOH) on silica-encapsulated superparamagnetic iron oxide nanoparticles (SPIONs) under solvent-free conditions successfully provided a powerful, efficient, and eco-friendly route for the synthesis of plasticizers. The turnover frequency value in micro-flow conditions varied in the range of 948.7 to 7384.6 h−1 compared to 403.8 to 3099 h−1 for in-flask. This technique works efficiently, encouraging future applications of micro-flow nano-catalysis in green chemistry.

An Investigation On The Structure Of Au(111)/Imidazolium-Based Ionic Liquid Interface: Effect Of Alkyl Side Chain Length, Li Chen, Shuai Liu, Mian-Gang Li, Jian-Jia Su, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

In this work, we comparatively investigated the interfacial structures at Au(111) electrode surfaces in two ionic liquids (ILs) with different alkyl chain lengths by combining AFM force curve technique and electrochemical methods. The number and stability of the layering structures, and their potential-dependency were analyzed. The experimental results indicated that the tendencies of force-potential curves in the two ILs behave the same way. At potentials close to PZC, the ions arrange loosely, which lowers the stability of the layering structure. As the potential shifting away from PZC, more ions attach to electrode surface, which increases the stability of layering structure, …

Preparation Of Nanoprobes And Their Possible Applications In Nanoscale Scanning Electrochemical Microscopy For Studying Electrocatalytic Oxygen And Hydrogen Reactions, Xing-Xing Chen

Journal of Electrochemistry

Scanning electrochemical microscopy (SECM) is a type of scanning probe microscopy, which can not only provide the topographical information, but also offer the electrochemical properties of different samples. The interrelationship of physical and electrochemical properties of a sample can be searched at a high-resolution scale due to the introduction of ultramicroelectrode (UME). With the continuous development of modern nanotechnology, the SECM probe has been improved with drastically decreasing its size down to nanometer. Meanwhile, to evaluate and understand the electrochemical performance of various electrocatalysts for both oxygen and hydrogen reactions with high-efficiency is highly demanded in the research area of …

Recent Advances In Non-Noble Metal Nanomaterials For Oxygen Evolution Electrocatalysis, Dan-Dan Zhao, Nan Zhang, Ling-Zheng Bu, Qi Shao, Xiao-Qing Huang

Journal of Electrochemistry

Hydrogen is a kind of renewable energies with the merits of environmentally friendly, abundance and high weight energy density, which can replace the fossil energy. The electrolysis of water is regarded as the most effective way to generate hydrogen. Owing to the sluggish kinetics and large overpotential of the anode oxygen evolution reaction (OER), the efficiency of the cathode hydrogen evolution reaction is greatly limited. Therefore, it is highly desirable to explore efficient, stable and low cost electrocatalysts to reduce the overpotential of OER and improve the efficiency of hydrogen evolution. Based on the natural characteristics of non-noble metal catalysts …

Complex Coordination Silver Electrocrystallization Mechanism On Glassy Carbon Electrode Surface, Shuai-Shuai Huang, Cheng Liu, Lei Jin, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min. Zhou

Journal of Electrochemistry

Cyclic voltammetry and potential step methods were successfully used to study the electrochemical crystallization mechanism of silver deposition on glassy carbon electrode (GCE) in the practical cyanide-free silver plating electrolyte containing composite complexing agents. Scharifker-Hill (SH) theory was used to fitting the experimental data. The results showed that the electrodeposition of silver is a diffusion controlled irreversible electrode process according to three-dimensional instantaneous nucleation mechanism. When the step potential shifted from -750 mV to -825 mV, the peak deposition current Im was increased, while the induced nucleation time tm shortened. The calculated kinetic parameters showed that the diffusion coefficient (D) …

Preparations Of Nano-Manganite Loaded Titanium Electocatalytic Membrane Electrode For Phenolic Wastewater Treatment, Le Li, Hong Wang, Rong-Hua Ma, Hong-Sen Hui, Xiao-Ping Liang, Jian-Xin Li

Journal of Electrochemistry

Nano-manganese oxide loaded on titanium electrocatalytic membrane electrodes (nano-MnO_x/Ti) were synthesized bysol-gel method using porous Ti membrane as a substrate and the manganese acetate as a raw material without releasing NO_x. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Field-emission scanning electron microscopy (FESEM) were employed to characterize crystal form, valence state and surface morphology of nano-MnO_x, respectively. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to investigate the electrochemical properties of nano-MnO_x electrode. The results indicated that the MnO_x catalysts consisted of γ-MnO₂ and Mn_{2 …}

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Pt/G-C3N4 Nanosheet For Visible Light-Induced Enhancement Of The Activity For Formic Acid Electro-Oxidation, Yong-Rong Sun, Chun-Yu Du, Guo-Kang Han, Ya-Jing Wang, Yun-Zhi Gao, Ge-Ping Yin

Journal of Electrochemistry

By using graphitic carbon nitride nanosheet (g-C₃N₄ nanosheet) as a support,Pt/g-C₃N₄ nanosheet catalyst was fabricated by microwave assisted polylol process. The nanoparticles size,composition,structure and optical properties of Pt/g-C₃N₄ nanosheet were characterized by TEM,XRD,XPS and UV-Vis diffuse reflectance spectroscopy. Comparing with the catalytic activities toward formic acid electro-oxidation under dark and visible light illumination,the superior activity of Pt/g-C₃N₄ nanosheet catalyst was achieved under visible light illumination. This visible light-driven enhancement in the formic acid performance could be attributed to the plasmon-induced electron-hole separation on g-C₃N₄ with …

Carbon Composite Fe3O4 Nanoparticles Based Electrochemical Sensor For Hydrogen Peroxide Detection, Si-Yu Zhang, Hui-Juan Wang, Shu-Fang Li, Jian-Ying Qu

Journal of Electrochemistry

In this work, a novel hydrogen peroxide electrochemical sensor was constructed with ferroferric oxide (Fe₃O₄) magnetic nanoparticles, which demonstrated good electrocatalytic activity for hydrogen peroxide. There existed a good linear relationship between the concentration of hydrogen peroxide and the oxidation peak current in the range of 1.00 × 10^-6 ~ 1.00 × 10^-3 mol·L^-1 (R = 0.9980) with the detection limit of 6.60 × 10-7 mol·L^-1. The sensor exhibited good anti-interference ability, high reproducibility and stability.

Lead Modified Nanoporous Platinum Electro-Catalysts For Formic Acid Oxidation, Yuan-Yuan Zhang, Qing-Feng Yi, Ge-Kun-Kun Zuo, Tao Zou, Xiao-Ping Liu, Xiu-Lin Zhou

Journal of Electrochemistry

Platinum (Pt) catalysts modified by other suitable metals significantly enhance their electrochemical activities for formic acid oxidation. In this work, a titanium-supported nanoporous network platinum (nanoPt/Ti) electrode was prepared using a hydrothermal method. The as-prepared nanoPt/Ti electrode was modified with a certain amount of lead by using cyclic voltammetry for different scan cycle numbers (n), namely, n = 10, 15, 20 and 30, to synthesize the novel lead-modified nanoporous Pt (nanoPb_(n)-Pt/Ti) electrodes. Electro-oxidation of formic acid on these electrodes was studied with cyclic voltammetry (CV), chronoamperometry and chronopotentiometry in sulfuric acid solution. CV curves showed that both nanoPt/Ti …

Dft Study Of Water Assisted Hydrogen Dissociation On Gold Nanoparticles, Jia-Li Chen, Xia-Guang Zhang, De-Yin Wu, Zhong-Qun Tian

Journal of Electrochemistry

The gold nanoparticles (GNPs) show special activity toward hydrogen (H₂) dissociation, comparing with bulk gold. Such activity is significantly affected by the existence of water. To inspect the influence of water on GNPs catalyzed H₂ dissociation, we carried out density functional theory (DFT) calculations along the reaction paths for water clusters (H₂O)_m (m = 1, 2, 3, 7) assisted H₂ dissociation on gold clusters (Au_n^δ, n = 3 ~ 5; δ = 0, 1). Our calculated results show that water benefits to the H₂ dissociation. The dissociation mechanism varies …

Oxidation Of N-Doped Multiwalled Carbon Nanotubes And Formation Of Discontinuous Spiraled Carbon Nanoribbons, Aman Preet Kaur, Mark S. Meier, Rodney Andrews, Dali Qian

Chemistry Faculty Publications

The effects of five commonly used wet chemical oxidations were studied for the extent of oxidation of graphitized nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs). KMnO₄/ H₂SO₄ was the most potent oxidant, as it produced the highest fraction of oxygen-containing functional groups. Electron microscopy studies showed that the treatment of annealed N-MWCNTs (G-N-MWCNTs) with H₂SO₄/HNO₃ and H₂SO₄/KMnO₄ mixtures leads to interesting spiraled ribbon textures. A structural model, involving the stacking of coiled subunits to form a discontinuous carbon nanoribbon rather than a continuous ribbon is proposed to …

From Flasks To Applications: Design And Optimization Of Giant Quantum Dots Using Traditional And Automated Synthetic Methods, Christina J. Hanson

Nanoscience and Microsystems ETDs

Semiconducting nanocrystals, also known as quantum dots (QDs), that emit light with near-unity quantum yield and are extremely photostable are attractive options as down-conversion and direct electricity-to-light materials for a variety of applications including solid-state lighting, display technologies, bio-imaging and optical tracking. Standard QDs with a core/thin shell structure display fluorescence intermittency (blinking) and photobleaching when exposed to prolonged room temperature excitation for single dot measurements, as well as significant reabsorption and energy transfer when densely packed into polymers or at high solution concentrations.

We have developed thick shell “giant” QDs (gQDs), ultra-stable photon sources both at the ensemble and …

Functionalized Nanoporous Carbon Scaffolds For Hydrogen Storage Applications, Christopher Carr

Dissertations

Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH₄and NaAlH₄indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of …

Dynamics Of Singlet Fission And Electron Injection In Self-Assembled Acene Monolayers On Titanium Dioxide, Natalie A. Pace, Dylan H. Arias, Devin B. Granger, Steven Christensen, John E. Anthony, Justin C. Johnson

Chemistry Faculty Publications

We employ a combination of linear spectroscopy, electrochemistry, and transient absorption spectroscopy to characterize the interplay between electron transfer and singlet fission dynamics in polyacene-based dyes attached to nanostructured TiO₂. For triisopropyl silylethynyl (TIPS)-pentacene, we find that the singlet fission time constant increases to 6.5 ps on a nanostructured TiO₂ surface relative to a thin film time constant of 150 fs, and that triplets do not dissociate after they are formed. In contrast, TIPS-tetracene singlets quickly dissociate in 2 ps at the molecule/TiO₂ interface, and this dissociation outcompetes the relatively slow singlet fission process. The addition …