Quartz Crystal Microbalance (QCM) in High-Pressure Carbon Dioxide (CO₂):  Experimental Aspects of QCM Theory and CO₂ Adsorption

Abstract

The quartz crystal microbalance (QCM) technique has been developed into a powerful tool for the study of solid-fluid interfaces. This study focuses on the applications of QCM in high-pressure carbon dioxide (CO2) systems. Frequency responses of six QCM crystals with different electrode materials (silver or gold) and roughness values were determined in helium, nitrogen, and carbon dioxide at 35-40 degrees C and at elevated pressures up to 3200 psi. The goal is to experimentally examine the applicability of the traditional QCM theory in high-pressure systems and determine the adsorption of CO2 on the metal surfaces. A new QCM calculation approach was formulated to consider the surface roughness contribution to the frequency shift. It was found that the frequency-roughness correlation factor, Cr, in the new model was critical to the accurate calculation of mass changes on the crystal surface. Experiments and calculations demonstrated that the adsorption (or condensation) of gaseous and supercritical CO2 onto the silver and gold surfaces was as high as 3.6 microg cm(-2) at 40 degrees C when the CO2 densities are lower than 0.85 g cm(-3). The utilization of QCM crystals with different roughness in determining the adsorption of CO2 is also discussed.

Impedance analysis for characterizing the influence of hydrostatic pressure on piezoelectric quartz crystal sensors

“…Wu et al 29 have shown that these additional effects are much smaller than the influence of viscosity when resonators with polished surfaces are immersed in fluids chemically inert. Besides the influence of viscous damping, the adsorption and the slipping of molecules from the gas phase, the roughness of the electrode surface of the quartz resonator may lead to variations ⌬f sl , ⌬f R in the resonance frequency of the crystal.…”

Dual quartz crystal microbalance for hydrogen storage in carbon nanotubes

“…This behavior was reproducible in response to the pressure. A plateau in the frequency-shift curve from the reference QCM was observed before and interpreted as a pressure-induced effect [21]. However, in good contrast with the reference QCM, a significant frequency drop in the SWCNT-loaded QCM is ascribed to the hydrogen adsorption.…”

Dynamics of Vapor-phase Organophosphates on Silicon and OTS

“…The QCM technique is particularly well adapted for measurements of uptake rates of vapor-phase lubricants, providing a sensitive, real-time means for monitoring mass uptake [10], and tribological properties of the adsorbed film and/or its reaction products [7,8,11]. QCM is also an attractive technique for comparative studies of macroscopic and microscopic phenomena, owing to the high-sliding speeds (up to 2 m/s) and shear rates at which the data are recorded [12].…”