Advanced and In Situ Analytical Methods for Solar Fuel Materials

Abstract

In situ and operando techniques can play important roles in the development of better performing photoelectrodes, photocatalysts, and electrocatalysts by helping to elucidate crucial intermediates and mechanistic steps. The development of high throughput screening methods has also accelerated the evaluation of relevant photoelectrochemical and electrochemical properties for new solar fuel materials. In this chapter, several in situ and high throughput characterization tools are discussed in detail along with their impact on our understanding of solar fuel materials.

Estimation and correction of instrument artefacts in dynamic impedance spectra

“…These artefacts can result in the wrong interpretation of the reaction mechanism or the extraction of wrong kinetic parameters. Several methods for identifying artefacts arising from cell setup and procedures for avoiding and/or correcting these artefacts have been reported in literature 4,5,[7][8][9][10][11][12][13] .Following the works of Fletcher 7 and Sadkowski et al 8 , Battistel et al proposed solutions to circumvent the artefacts occurring in a three-electrode cell setup 4 . It comprises of using a three-electrode cell in a coaxial geometry and a capacitive bridge between the working electrode and reference electrode 4 .…”

“…Tran et al with the help of simulations explained the use of low impedance reference electrode fabricated by connecting a platinum wire to the reference electrode through a capacitor, which has been used in circumventing high-frequency artefacts [14][15][16] . Low impedance reference electrodes were used to circumvent high-frequency artefacts during the acquisition of dynamic impedance spectra of cathode materials for aqueous batteries such as nickel hexacyanoferrate thin films and LiMn 2 O 4 films 17,18 .A zero-gap cell combined with by-pass modified and sensing electrodes was proposed by Stojadinovic and co-workers to minimize distortions arising from artefacts in a four-electrode cell setup 10,19 . The use of a fourprobe setup to measure high impedance values (up to 10 G ) to circumvent artefacts arising from four-electrode cell setup has been demonstrated by Fafilek et al 5 .…”

“…The use of a fourprobe setup to measure high impedance values (up to 10 G ) to circumvent artefacts arising from four-electrode cell setup has been demonstrated by Fafilek et al 5 . Finite element method (FEM) simulations have also been used as a means of identifying limiting conditions for reliable impedance measurement in three-electrode cell setup for lithium-ion batteries 20,21 . To avoid artefacts arising from geometric and electrochemical asymmetries, Klink et al suggested the use of modified Swagelok cells with precisely aligned electrodes and a coaxially located reference electrode 22 .The aforementioned methods reduce and/or eliminate artefacts arising from cell setups, but they do not address artefacts arising from the instrument setup.…”

“…Finite element method (FEM) simulations have also been used as a means of identifying limiting conditions for reliable impedance measurement in three-electrode cell setup for lithium-ion batteries 20,21 . To avoid artefacts arising from geometric and electrochemical asymmetries, Klink et al suggested the use of modified Swagelok cells with precisely aligned electrodes and a coaxially located reference electrode 22 .The aforementioned methods reduce and/or eliminate artefacts arising from cell setups, but they do not address artefacts arising from the instrument setup. The instrument setup used for the data acquisition in EIS contains parts (cables, voltage and current amplifiers), which deviates from ideal behaviour at high frequencies 4 .…”

“…These artefacts can result in the wrong interpretation of the reaction mechanism or the extraction of wrong kinetic parameters. Several methods for identifying artefacts arising from cell setup and procedures for avoiding and/or correcting these artefacts have been reported in literature 4,5,[7][8][9][10][11][12][13] .…”