Surface chemistry is the study of the phenomenon and reactions taking place on the surfaces of substances. Surface chemistry is something that impacts industries in day to day lives.
Surface chemistry occurs at the interface of a solid surface. This could be a solid-liquid or solid-gas interface. Some examples of phenomena taking place in surface chemistry are:
- Heterogeneous catalysis
- Adsorption
- Crystallization
- Corrosion
What is Desorption?
Desorption is a surface chemistry process in which a substance is released from. This process is the opposite of adsorption and takes place in a system that is in the state of sorption equilibrium between the gas/liquid bulk and an adsorbing surface. When the pressure or concentration of the substance in the bulk phase is decreased, some of the sorbed substance transfers into the bulk state. The capacity of desorbing is known as desorptive capacity.
Reductive or oxidative desorption
In some instances, an adsorbed molecule has a chemical bond to the surface/material. This offers strong adhesion and limits desorption. In these cases, desorption needs a chemical reaction that breaks these chemical bonds. Electrochemistry can be used as a method to initiate chemical reaction by applying a voltage to the surface allows this to happen and results in either oxidation or reduction of the adsorbed molecule.
Temperature Programmed Desorption
TPD is a widely-used analytical method employed for investigating surface chemistry in UHV and atmospheric pressure conditions. TPD can be employed for probing the kinetic parameters of catalyst surface reactions, rate constants, site coverage, concentration, and reactivity. All of these offer an understanding of particular reaction mechanisms.
In recent times, researchers have been more able to drill downwards to the molecular level within heterogeneous catalyst research employing such techniques as steady-state isotopic transient kinetic analysis (SSITKA).
Methane Oxidation
Decreasing damaging emissions is one of the key focuses of modern catalysts. Complete methane oxidation is extremely important to prevent the release of unburnt methane into the atmosphere. Methane has a much greater effect than CO2 as a greenhouse gas. Additionally control of methane oxidation, in turn, would significantly decrease the amount of nitric oxide, carbon monoxide, and non-oxidized hydrocarbon emissions being released into the atmosphere.
How can SSITKA Analysis be Carried Out
SSITKA analysis in surface chemistry can use quadrupole mass spectrometry systems for fast isotope switching gas analysis events at near atmospheric pressures. Mass spectrometry can be beneficial in surface chemistry as an analytical method that quantifies the mass-to-charge ratio of charged particles and so can be used to detect different isotopes of probe gases.
