Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Catalysis02:50

Catalysis

28.1K
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
28.1K
E1 Reaction: Kinetics and Mechanism02:46

E1 Reaction: Kinetics and Mechanism

16.0K
Here, in contrast to the E2 reaction mechanism, we delve into the aspects of the E1 reaction mechanism, which has two steps: rate-limiting loss of the leaving group and abstraction of the beta hydrogen by a weak base. Typically, the experimental proof for the E1 mechanism is via kinetic studies or isotope studies. While the former demonstrates the first-order kinetics—the dependence of the reaction solely on substrate concentration—the latter proves the abstraction of hydrogen only...
16.0K
E2 Reaction: Kinetics and Mechanism02:45

E2 Reaction: Kinetics and Mechanism

10.9K
SN2 substitutions and E2 eliminations of alkyl halides proceed via a concerted pathway. While the nucleophile attacks the alpha carbon in SN2 reactions, it functions as a strong base and abstracts a beta hydrogen in the E2 mechanism. The rate-limiting transition state in E2 elimination reactions is characterized by partially broken carbon–hydrogen and carbon–halogen bonds and a partially formed pi bond between the alpha and beta carbons. The beta hydrogen and halide are eliminated...
10.9K
SN2 Reaction: Kinetics02:14

SN2 Reaction: Kinetics

9.0K
Kinetic Studies and Significance
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a...
9.0K
Reduction of Alkenes: Catalytic Hydrogenation02:13

Reduction of Alkenes: Catalytic Hydrogenation

12.7K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
12.7K
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation02:17

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

3.5K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.5K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Silicon-Mediated Laser Shock Synthesis of Nanocrystalline Diamonds from Low-Rank Coal.

ACS nano·2026
Same author

From Cation Solvation to Anion Coordination: Lewis-Acidic Boranes Enable Halide Salt Electrolytes.

The journal of physical chemistry. B·2026
Same author

Increasingly Reversible Na/Cl<sub>2</sub> and Li/Cl<sub>2</sub> Batteries.

Journal of the American Chemical Society·2026
Same author

Lignin-Functionalized Supramolecular Binder Enables Aggressive Cathode Chemistries in Advanced Li-Ion Batteries.

Journal of the American Chemical Society·2026
Same author

AI-guided design of efficient perovskite solar cells operationally stable at 100°C.

Science (New York, N.Y.)·2026
Same author

Mott state of flat bands in a 2D metal-organic Kagome framework.

National science review·2026

Related Experiment Video

Updated: Oct 14, 2025

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
10:01

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Published on: December 4, 2017

12.4K

Cation- and pH-Dependent Hydrogen Evolution and Oxidation Reaction Kinetics.

Botao Huang1,2, Reshma R Rao1,2, Sifan You3

  • 1Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.

JACS Au
|November 1, 2021
PubMed
Summary

Spectator cations significantly alter hydrogen evolution and oxidation reactions (HER/HOR) kinetics. Cation structure-making tendency correlates with increased HER/HOR rates and modified interfacial water structure.

More Related Videos

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
10:21

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions

Published on: October 5, 2019

8.5K
Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
10:57

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Published on: April 10, 2018

18.5K

Related Experiment Videos

Last Updated: Oct 14, 2025

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
10:01

Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase

Published on: December 4, 2017

12.4K
Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
10:21

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions

Published on: October 5, 2019

8.5K
Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
10:57

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Published on: April 10, 2018

18.5K

Area of Science:

  • Electrochemistry
  • Catalysis
  • Physical Chemistry

Background:

  • Molecular hydrogen production via water splitting is crucial for sustainable fuels and decarbonization.
  • Hydrogen evolution and oxidation reactions (HER/HOR) are key catalytic processes.
  • Electrolyte composition, particularly spectator cations, can influence reaction kinetics.

Purpose of the Study:

  • To investigate the effect of structure-making/breaking spectator cations on HER/HOR kinetics across a wide pH range (1-14).
  • To elucidate the relationship between cation properties, interfacial water structure, and reaction mechanisms.
  • To explore methods for controlling HER/HOR rates through interfacial engineering.

Main Methods:

  • Experimental investigation of HER/HOR kinetics using various spectator cations (Cs+, Rb+, K+, Na+, Li+) on a platinum (Pt) surface.
  • Application of the Marcus-Hush-Chidsey formalism to analyze reorganization energy.
  • Utilizing the Born model to assess interfacial static dielectric constant and reaction entropy.
  • Classical molecular dynamics (MD) simulations and surface-enhanced infrared absorption spectroscopy (SEIRAS) to probe interfacial structure.

Main Results:

  • Cation choice altered HER/HOR kinetics by up to two orders of magnitude.
  • Exchange current density of HER/HOR increased with cation structure-making tendency (Cs+ < Rb+ < K+ < Na+ < Li+).
  • Decreasing reorganization energy and increasing reaction entropy correlated with enhanced kinetics.
  • Interfacial static dielectric constant was lower than bulk and decreased with cation structure-making tendency.
  • Cation accumulation at the Pt surface modified interfacial water structure and H-bonding networks.

Conclusions:

  • Spectator cations play a critical role in tuning HER/HOR kinetics by altering interfacial water structure and H-bonding.
  • The observed cation-dependent kinetics can be rationalized by changes in reorganization energy, reaction entropy, and interfacial dielectric properties.
  • Significant opportunities exist to optimize catalytic performance by manipulating cation-solvent interactions at the electrified interface.