Despite the growing popularity of cyclic voltammetry, many students do not receive formalized training in this technique as part of their coursework. Confronted with self-instruction, students can be left wondering where to start. Here, a short introduction to cyclic voltammetry is provided to help the reader with data acquisition and interpretation. Tips and common pitfalls are provided, and the reader is encouraged to apply what is learned in short, simple training modules provided in the Supporting Information. Armed with the basics, the motivated aspiring electrochemist will find existing resources more accessible and will progress much faster in the understanding of cyclic voltammetry.

All Rights Reserved iii For my mom iv ACKNOWLEDGEMENTSI would first like to thank Harry for his guidance over the last five years. Harry has supported my growth as a scientist beyond my wildest expectations-in addition to being the most sincere and caring mentor I could have hoped for, he has given me countless opportunities to define myself beyond the confines of the laboratory and gain exposure in the chemistry community. I could not have made it through these projects without his insight and encouragement, and for that I am truly blessed by this graduate experience.Second, I would like to thank Jay for his support and advice, teaching me everything I know about kinetics and spectroscopy, building me a diode array spectrometer, and routinely reminding me of the value of fundamental research. Like the best of mentors, he has challenged me to be an assertive researcher and calmly watched me freak out more than once. This thesis would not be nearly as comprehensive without his guidance.I have had some of the most rewarding scientific discussions of my graduate career with my thesis committee members, Mitchio Okumura, Nate Lewis, and Tom Miller, and I want to thank them for their support over the last five years. I would especially like to acknowledge Nate for giving me the opportunity to cochair the 2009 Renewable Energy: Solar Fuels Gordon-Kenan Graduate Research Seminar. I also want to thank Bruce Brunschwig and Jonas Peters who provided a good deal of guidance on this project.My undergraduate research advisor, Dan Nocera, has continued to support, encourage, and advise me over the five and a half years since I graduated from MIT. It is from Dan that I gained my love for group theory (5.04) and inorganic spectroscopy, and I am grateful for his continued guidance. I have enjoyed collaborating with a great many researchers during my graduate work.Etsuko Fujita, Dmitry Polyanskiy, and Jim Muckerman at Brookhaven National Laboratory have been enthusiastic about my research for many years and welcomed me into their labs for two visits. Etsuko in particular has been a great friend and role model and I look forward to maintaining our relationship for years to come. It has been a pleasure to make progress towards powering the planet with researchers in both the Lewis and Peters groups.Leslie O'Leary, Judy Lattimer, and Emily Warren have all made contributions towards anchoring cobaloxime catalysts to silicon electrodes, and Xile Hu, Louise Berben, Nate Szymczak, and Charles McCrory have all taught me a great deal about electrochemistry, synthesis, and catalytic hydrogen evolution.I have had the opportunity to work with a number of talented undergraduates at Caltech.Carolyn Valdez has been a great friend and I have been truly honored to watch her grow as a scientist over four years at Caltech. She spearheaded the binuclear cobaloxime catalyst project (Chapter 5), helped lead the Blair High School SHArK program, and is hands-down one of the best all-around undergraduates I ever met at Caltech. I am excited that we will b...

The pursuit of solar fuels has motivated extensive research on molecular electrocatalysts capable of evolving hydrogen from protic solutions, reducing CO2, and oxidizing water. Determining accurate figures of merit for these catalysts requires the careful and appropriate application of electroanalytical techniques. This Viewpoint first briefly presents the fundamentals of cyclic voltammetry and highlights practical experimental considerations before focusing on the application of cyclic voltammetry for the characterization of electrocatalysts. Key metrics for comparing catalysts, including the overpotential (η), potential for catalysis (E(cat)), observed rate constant (k(obs)), and potential-dependent turnover frequency, are discussed. The cyclic voltammetric responses for a general electrocatalytic one-electron reduction of a substrate are presented along with methods to extract figures of merit from these data. The extension of this analysis to more complex electrocatalytic schemes, such as those responsible for H2 evolution and CO2 reduction, is then discussed.

Molecular catalysts for electrochemically driven hydrogen evolution are often studied in acetonitrile with glassy carbon working electrodes and Brønsted acids. Surprisingly, little information is available regarding the potentials at which acids are directly reduced on glassy carbon. This work examines acid electroreduction in acetonitrile on glassy carbon electrodes by cyclic voltammetry. Reduction potentials, spanning a range exceeding 2 V, were found for 20 acids. The addition of 100 mM water was not found to shift the reduction potential of any acid studied, although current enhancement was observed for some acids. The data reported provides a guide for selecting acids to use in electrocatalysis experiments such that direct electrode reduction is avoided.

The exchange reactions of X-type ligands at the surface of CdSe nanocrystals have been quantified via 1 H NMR, absorbance, and emission spectroscopies. 1 H NMR was used to quantify displacement reactions of oleate-capped CdSe nanocrystals with carboxylic-acid-, phosphonic-acid-, and thiolterminated ligands that incorporate terminal alkene functionalities. The alkenyl protons of the native oleate ligand and the vinylic protons of the exchange ligand provide spectroscopic handles to quantify both free and surface-bound forms of these ligands. Undec-10-enoic acid was found to undergo an exchange equilibrium with oleate (K eq = 0.83), whereas phosphonic-acid-and thiol-terminated ligands irreversibly displace native oleate ligands. Absorption and emission experiments indicate that the carboxylic acid exchanges occur solely between surface-bound ligands, whereas exchange reactions with phosphonic acids and thiols alter the surface metal atoms of the nanocrystals, presumably through the displacement of Cd(oleate) 2 . These quantifications can be used to guide the selective functionalization of CdSe nanocrystals. ■ INTRODUCTIONResearch in the field of semiconductor quantum dots (QDs) has exploded since the discovery of their quantum size effects in 1983. 1 Their size tunable optical properties have been exploited for applications ranging from photovoltaic cells to solid-state lighting. 2,3 As synthesized, colloidal QDs are composed of an inorganic semiconductor core and an organic ligand shell. These ligands, generally long chain fatty acids, aid in the growth and stabilization of QDs, solubilize QDs in organic solvents, and passivate undercoordinated surface atoms of the QD. However, these native ligands are not ideal for many QD applications, and can be exchanged for other coordinating ligands which may vary in the surface anchoring group, chain length, and chain identity. Ligand exchanges are commonly performed to incorporate functional groups that alter QD solubility, introduce electron transfer partners, or integrate biological receptors. 4−26 The extent of these ligand exchange reactions must be controlled if a limited number of functionalized ligands per nanocrystal is desired.Although ligand exchange reactions are commonly employed, the mechanisms and principles that govern these processes are not explicitly understood. 27 Many studies have been conducted monitoring the surface chemistry of quantum dots using photoluminescence spectroscopy, 1 H NMR spectroscopy, as well as diffusion-ordered NMR spectroscopy (DOSY), nuclear Overhauser effect spectroscopy (NOESY), and 31 P NMR spectroscopy. 10,12,26,28−43 Among the studies focused on oleatecapped metal chalcogenide nanocrystals, Hens and co-workers have employed these NMR methods to examine the details of various ligand exchange reactions. Through these experiments, they determined that phosphonic acids displace oleate ligands with a 1:1 stoichiometry, 31 and that the self-exchange of oleic acid (OA)/oleate at the surface of CdSe QDs involves a proton exchange. 33...