A quantitative methodology for the study of particle–electrode impacts

Abstract

Herein we provide a generic framework for use in the acquisition and analysis of the electrochemical responses of individual nanoparticles, summarising aspects that must be considered to avoid mis-interpretation of data. Specifically, we threefold highlight the importance of the nanoparticle shape, the effect of the nanoparticle diffusion coefficient on the probability of it being observed and the influence of the used measurement bandwidth. Using the oxidation of silver nanoparticles as a model system, it is evidenced that when all of the above have been accounted for, the experimental data is consistent with being associated with the complete oxidation of the nanoparticles (50 nm diameter). The duration of many single nanoparticle events are found to be ca. milliseconds in duration over a range of experiments. Consequently, the insight that the use of lower frequency filtered data yields a more accurate description of the charge passed during a nano-event is likely widely applicable to this class of experiment; thus we report a generic methodology. Conversely, information regarding the dynamics of the nano redox event is obscured when using such lower frequency measurements; hence, both data sets are complementary and are required to provide full insight into the behaviour of the reactions at the nanoscale.

Nano Impact Electrochemistry: Effects of Electronic Filtering on Peak Height, Duration and Area

“…Generally, the use of low‐bandwidth filtering conditions can improve the SNR by suppressing background noise in the system . However, in case of nano impact experiments with very short impact duration (<1 ms), using the low‐bandwidth filter can have a negative effect to the SNR as the impulse amplitude is also reduced by the filter.…”

“…This costly requirement can be partially minimized by an external analogue filter, in which the sampling rate can be decreased to be proportional to the filter bandwidth. Unfortunately, as the transfer function of both amplifier and filter is not an ideal brick‐wall filter, the significantly‐higher sampling rate is necessary for the accurate digital filtering, i. e. up to 50 times of the bandwidth . This limits the utility of the digital filtering in practical time‐resolved experiments, where high‐bandwidth measurements are necessary.…”

“…Additionally, the electronic noise is also higher due to the higher bandwidth of the filtering system. As shown in Figure , particle diameters calculated from the integral peak charge are not affected by the filter as the charge is conserved as reported earlier ,. Nevertheless, lengthening of peak duration at low frequencies may yield erroneous diffusion coefficients if calculated from Equation 4.…”

Electroanalytic Aspects of Single‐Entity Collision Methods for Bioanalytical and Environmental Applications

“…Therefore, the choice of electrolyte and its concentration should be thoroughly optimized before considering this method for analytical measurement purposes. It was also reported that frequency filters reduce the signal to noise ratio, however, they can contribute to a loss of individual current spikes and alter current peak features . Collision measurements also depend on the nature and surface treatment of the electrode used, as well as the NP and the redox process that is monitored.…”

A Method for Voltage Noise Measurement and Its Application to Primary Batteries

“…These techniques elucidate the underlying processes to both diagnose the state of the systems and also gain insights to increase next generation performances. 1,2 Electrochemical noise measurements with the appropriate measurement and signal processing routines are expected to be relevant in this regard where electrochemical noise can be a vital indicator of the underlying processes that occur even at an apparent equilibrium. Especially for primary chemistries that are inherently not rechargeable, nondestructive/equilibrium techniques such as electrochemical noise is attractive where conventional techniques deplete the battery in question during the quality control process.…”