Electrochemical Desorption Research Articles

Investigation of the geometrical arrangement and single molecule charge transport in self-assembled monolayers of molecular towers based on tetraphenylmethane tripod

Multipodal molecular platforms were designed recently to establish a well-defined contact between molecular electronic components and metallic electrodes to manufacture working devices based on molecular electronics. In this work, we use electrochemical techniques, scanning tunneling microscopy break junction technique and theoretical approaches combining density functional theory (DFT) and non-equilibrium Green's function (NEGF) formalism to investigate the geometrical arrangement and single molecule charge transport in self-assembled monolayers (SAMs) of molecular towers anchored by tetraphenylmethane tripod on Au (111) surface. The effect of the molecular length as well as the role of the position of anchoring groups was addressed. Electrochemical double-layer capacitance measurements and reductive desorption studies combined with theoretical modeling clearly demonstrated that the molecular towers form densely packed SAMs, in which the individual molecules are attached to the Au (111) surface by the tripodal base and the principal molecular axis is directed away from the electrode surface, providing thus desired orientation. Temperature resolved single molecule conductance measurements combined with DFT/NEGF calculations showed that the electric charge is transported by tunneling via highly conductive molecular junctions formed by the tripodal base. Our combined experimental and theoretical work demonstrates that tetraphenylmethane tripods are suitable platforms to bear functional groups serving as molecular electronic components.

Electrochemical and SECM Investigation of MoS2/GO and MoS2/rGO Nanocomposite Materials for HER Electrocatalysis.

Development of advanced materials for electrocatalytic and photocatalytic water splitting is the key in utilization of renewable energy. In the present work, we have synthesized MoS2 nanoparticles embedded over the graphene oxide (GO) and reduced graphene oxide (rGO) layer for superior catalytic activity in the hydrogen evolution process (HER). The nanocomposite materials are characterized using different spectroscopic and microscopic measurements. A Tafel slope of ∼40 mV/decade suggested the Volmer–Heyrovsky mechanism for the HER process with MoS2/GO composite as the catalyst, which indicated that electrochemical desorption of hydrogen is the rate-limiting step. The small Tafel slope indicates a promising electrocatalyst for HER in practical application. MoS2/GO composite material has shown superior catalytic behavior compared to that of MoS2/rGO composite material. The HER catalytic activity of the catalysts is explored using scanning electrochemical microscopy (SECM) using the feedback and redox competition mode in SECM. The activation energy for HER activity was calculated, and the values are in the range of 17–6 kJ/mol. The lower value of activation energy suggested faster HER kinetics.

Highly Efficient Capture and Electrochemical Release of Circulating Tumor Cells by Using Aptamers Modified Gold Nanowire Arrays.

The effective capture and release of circulating tumor cells (CTCs) is of significant importance in cancer prognose and treatment. Here we report a highly efficient method to capture and release human leukemic lymphoblasts (CCRF-CEM) using aptamers modified gold nanowire arrays (AuNWs). The gold nanowires, showing tunable morphologies from relatively random pillar deposit to relatively uniform arrays, were fabricated by electrochemical deposition using anodic aluminum oxide (AAO) as template. Upon simply being modified with aptamers by Au-S chemistry, the AuNWs exhibit higher specificity to target cells. Also compared to flat gold substrate, the AuNWs with nanostructure can capture target cells with much higher capture yield. Moreover, the captured CCRF-CEM cells can be released from AuNWs efficiently with little damage through an electrochemical desorption process. We predict that our strategy has great potential in providing a simple and economical platform for CTCs isolation, cancer diagnosis, and therapy.

Intensified electrochemical hydrogen storage capacity of multi-walled carbon nanotubes supported with Ni nanoparticles

The electrochemical hydrogen storage properties of Ni-supported multi-walled carbon nanotube (Ni/MWCNT) electrodes were investigated using charge/discharge (C&D) and cyclic voltammetry (CV) techniques. Nickel NPs were deposited on the MWCNT surface, which was first chemically oxidized by H2SO4 and HNO3 (3:1, v/v). Hydrogen storage was carried out by using the Ni/MWCNT electrode as the working electrode in the electrochemical cell. A set of various current densities were applied to the cell to produce (C&D) cycles, and it became optimum corresponding to 1.5 mA current. According to the electrochemical test results, the highest electrochemical discharge capacity of 1625 mAh g−1 was obtained for the electrode with ratio of 4:1 (MWCNTs to Ni) in the initial cycle, which corresponded to 6.07 wt% H2. The storage capacity was increased and reached to 4909 mAh g−1 (18.34 wt% H2) after 20 cycles, and the electrode maintained the specific capacity as cycling continued. Thus, the Ni/MWCNT electrode displays an excellent cycle stability and a high capacity reversibility. CV measurements also showed that the electrochemical adsorption and desorption amount of hydrogen was increased by Ni loading onto the CNTs and indicated that the electrochemical hydrogen adsorption of the electrode has an activated period.

Diamine anchored molecular junctions of oligo(phenylene ethynylene) cruciform

Using diamine as anchoring group, the self-assembled monolayers (SAMs) based on oligo(phenylene-ethynylene)s (OPEs) and cruciform OPEs with an extended tetrathiafulvalene (TTF) (OPE3 and OPE3-TTF) were successfully formed on the Au substrate. The uniformity and stability of SAMs were confirmed through cyclic voltammetry (CV) and electrochemical reductive desorption. The investigation of transport properties of SAMs was achieved by conducting-probe atomic force microscopy (CP-AFM) with both Au and Pt tips. The results indicated that the conductance of OPE3-TTF was 17 and 46 times that of OPE3 for Au and Pt tips, respectively. Theoretical calculations are qualitatively consistent with the experimental results, suggesting that the diamine as anchoring group has a great potential in molecular electronics.

Electrochemical THz-SERS Observation of Thiol Monolayers on Au(111) and (100) Using Nanoparticle-assisted Gap-Mode Plasmon Excitation.

Surface-enhanced Raman scattering (SERS) microscopy using nanoparticle-assisted gap-mode plasmon excitation, which enables us to observe an atomically defined planar metal surface, was combined with THz-Raman spectroscopy to observe ultra-low-frequency vibration modes under electrochemical conditions. This combination helps us to gain deeper insights into electrode/electrolyte interfaces via direct observation of extramolecular vibrations including information on intermolecular and substrate/molecule interactions. Electrochemical reductive desorption of benzenethiol derivatives from Au(111) and (100) was monitored to demonstrate the power of this spectroscopy. Structural differences of the monolayers between these surfaces were seen only in the extramolecular vibration modes such as a large-amplitude hinge-bending motion of the phenyl ring. On the Au(111), where hollow-site and bridge-site adsorption coexisted, the electrochemical reductive desorption was preferentially induced at the hollow sites.

Voltammetric aptamer based detection of HepG2 tumor cells by using an indium tin oxide electrode array and multifunctional nanoprobes

The authors describe a method for the detection and determination of human liver cancer cells in blood. The cytosensing system consists of a microfabricated chip-based electrochemical aptasensor that contains multifunctional hybrid electrochemical nanoprobes and an indium tin oxide (ITO) electrode array interface functionalized with cell-targeting aptamer and gold nanoparticles (AuNPs). The thiolated cell targeting aptamer (referred to as TLS11a) was immobilized on the ITO electrode/AuNPs for specific adhesion of hepatocellular carcinoma cells (HepG2). The hybrid nanoprobe system consists of hydroquinone (HQ) as an electrochemical probe, horseradish peroxidase (HRP), and an aptamer/hemin/G-quadruplex aggregate that was immobilized on gold/palladium-functionalized ZnO nanorods (ZnO@Au-Pd). The nanoprobes are capable of amplifying the voltammetric signal and capturing the target cells. Best operated at around −90 mV (vs Ag/AgCl), the electrode has a linear response that covers the 10^2 to 10^7 HepG2 cells per mL concentration range, with a 10 cell per mL detection limit. Captured cells may be released from the electrode via electrochemical desorption to break the Au-S bonds.

Active sites and mechanism on nitrogen-doped carbon catalyst for hydrogen evolution reaction

The nature of active sites and mechanism of hydrogen evolution reaction (HER) on the nitrogen-doped carbon catalyst is extensively investigated, by combining physicochemical and electrochemical methods. Two carbon catalysts, with the same chemical nature but different nitrogen content, are employed in this investigation. Electrochemical methods are applied to investigate the electrochemical behavior at different pH values (1.0–2.0, 12.0–13.0). It is found that increasing nitrogen content has a positive effect on the electrocatalytic activity, and therefore, the doped nitrogen atoms should be the active sites. The kinetic current, normalized by the surface nitrogen content, is found to be the same for the two catalysts, confirming the above claim. As such, HER is proposed to proceed on these active sites by the Volmer-Heyrovsky mechanism. The electrochemical tests reveal that the electrocatalytic activity closely relies on the solution pH, which is due to the chemical evolution of the active site in different solutions. In acid media, the electrocatalytic activity increases with the concentration of proton, and the Tafel slope is ca. 120mVdec−1. It is proposed that the electrochemical desorption of proton on the doped nitrogen atoms is the rate determining step (r.d.s.). In alkaline media, the electrocatalytic activity increases with pH, because the increase in pH dramatically enhances the basicity or the surface charge density, thereby facilitating charge transfer and improving activity. In alkaline media, Tafel analysis shows that Heyrovsky step is the rate determining.

A voltammetric aptamer-based thrombin biosensor exploiting signal amplification via synergetic catalysis by DNAzyme and enzyme decorated AuPd nanoparticles on a poly(o-phenylenediamine) support

A regenerable and ultrasensitive voltammetric biosensor is described for the determination of thrombin. It relies on a combination of (a) enzymatic catalysis, (b) a G-quadruplex/hemin DNAzyme system, and (c) AuPd nanoparticles for signal amplification. Poly(o-phenylenediamine) was decorated with AuPd nanoparticles and loaded with horseradish peroxidase (HRP) and thrombin aptamer (TBA), and the mixture was allowed to interact with hemin to form the G-quadruplex/hemin/HRP/AuPd/poly(o-phenylenediamine) bioconjugates. In the presence of thrombin, the bioconjugates remain immobilized on the surface of the modified glassy carbon electrode through a sandwich reaction. Poly(o-phenylenediamine) also acts as a redox mediator, and the electrochemical reaction of poly(o-phenylenediamine) in the presence of H2O2 is efficiently catalyzed by HRP, AuPd nanoparticles and G-quadruplex/hemin as the peroxidase mimics. Thus, a remarkably amplified electrochemical signal is obtained by the triple catalytic amplification. The biosensor has a dynamic range that spans the 100 f. to 20 nM thrombin concentration range, and the detection limit is 20 fM. The biosensor can be regenerated by applying an electrochemical desorption technique that breaks the gold-thiol bond and releases the components from the surface. In our perception, the mediator-free and signal-amplified biosensor demonstrated here has a large potential with respect to the quantitation of thrombin in clinical samples.

Catch-and-Release of Target Cells Using Aptamer-Conjugated Electroactive Zwitterionic Oligopeptide SAM

Nucleic acid aptamers possess attractive features such as specific molecular recognition, high-affinity binding, and rapid acquisition and replication, which could be feasible components for separating specific cells from other cell types. This study demonstrates that aptamers conjugated to an oligopeptide self-assembled monolayer (SAM) can be used to selectively trap human hepatic cancer cells from cell mixtures containing normal human hepatocytes or human fibroblasts. Molecular dynamics calculations have been performed to understand how the configurations of the aptamers are related to the experimental results of selective cell capture. We further demonstrate that the captured hepatic cancer cells can be detached and collected along with electrochemical desorption of the oligopeptide SAM, and by repeating these catch-and-release processes, target cells can be enriched. This combination of capture with aptamers and detachment with electrochemical reactions is a promising tool in various research fields ranging from basic cancer research to tissue engineering applications.

Dipole Moment Effect on the Electrochemical Desorption of Self‐Assembled Monolayers of 310‐Helicogenic Peptides on Gold

AbstractThe front cover artwork is provided by Pierangelo Gobbo and Flavio Maran, University of Padova (Italy). The image highlights how the orientation of the dipole moment associated with helical peptides affects the electrodesorption potential of the corresponding self‐assembled monolayers. Read the full text of the Article at 10.1002/celc.201600573.

Hydrogen evolution reaction on electrodeposited Zn-Cr alloy coatings

The hydrogen evolution reaction (HER) on electrodeposited Zn-Cr alloy coatings with different thickness and Cr content was investigated in a 0.5M Na2SO4 solution by electrochemical methods. The hydrogen evolution on the alloys starts at less negative potentials in comparison to that on Zn. Subsequently, with the potential shift in negative direction the rate of the HER on the alloy increases significantly faster. At low polarizing currents the hydrogen overvoltage on the alloys is closer to that on Zn, whereas at high polarizing currents it is closer to that on Cr. In the latter case the hydrogen overvoltage on the alloys is more than 200mV lower than that on Zn. The lowering of the hydrogen overvoltage is related to the Cr content in the alloy. Almost similar values of the exchange current density for the HER on the alloys (Cr content in the range of 3 to 10 mass %) are determined. Based on the derived Tafel slopes Volmer reaction mechanism for the hydrogen evolution reaction on the alloys within the 0.25–10mAcm−2 current density range could be proposed. At higher polarizing currents the effect of Cr becomes more pronounced and presumably the electrochemical desorption appears to be the likely rate determining step.

Nanostructured cobalt-modified molybdenum carbides electrocatalysts for hydrogen evolution reaction

A series of nanostructured catalysts based on cobalt-modified molybdenum carbides, intended as alternative replacement for platinum has been developed for the hydrogen evolution reaction (HER) from brine. The catalysts were synthesized by simple impregnation of the metal salts on carbon support and followed by pyrolysis in CH4 atmosphere. The obtained catalysts show impressive HER activities in both brine and alkaline media. At current density of −7.0 mA cm−2, the overpotential for Co modified Mo/C catalysts was greater than that obtained with a commercial Pt/C catalyst by 63–89 mV and 15–148 mV for brine and alkaline solution, respectively. Our findings for HER in both media are consistent with electrochemical desorption of hydrogen gas following the Volmer-Heyrovsky mechanism as the rate-determining step. The HER activities of the catalysts were correlated to their high mesopore surface areas with active pores, nanocrystallites, and low charge transfer resistances as confirmed by electrochemical impedance spectroscopy.

Reaction of hydrogen evolution on Co−Mo (W) and Ni−Re electrolytic alloys in alkaline media

The mathematical processing of experimental data is performed for the hydrogen evolution reaction (HER) in alkaline media on Co−Mo and Ni−Re cathodes obtained by electrodeposition. It is shown that it is necessary to take into account the possibility of occurrence of the stages of discharge (Volmer), electrochemical desorption (Heyrovský), and recombination of adsorbed hydrogen atoms (Tafel) in HER description on Co−Mo electrodes. Hydrogen evolution on Ni−Re cathodes is well modeled under the assumption of the Volmer–Heyrovský route (discharge and the following electrochemical desorption), but the contribution of diffusion of Hat into the cathode material is significant in the range of high cathodic current densities.

Electrochemical Synthesis of Single Pt Atom Catalyst for Hydrogen Reactions

Single metal atom/center catalysts that bridge heterogeneous and homogeneous catalysis have very recently attracted much attention for the maximum usage of noble metal atom and great potential to achieve high activity and selectivity [1]. Very recently, several techniques have been developed to achieve supported single platinum atom for catalysis on metal oxides including Al2O3 and iron oxides which have a strong interaction with platinum atoms [2,3]. One key issue is that the high surface free energy of metal atom usually induces aggregation of metal atoms into big clusters. These techniques, however, only allow metal atoms prepared on oxide materials. In this study, we investigated the possibility of preparing Pt atoms by using electrochemical deposition techniques and whether the Pt atoms can be deposited on non-oxide materials. The result to the question turned out to be in the affirmative, yielding Pt atoms on carbon materials in addition to metal oxides. According to the two-electron-reaction models, cathodic hydrogen evolution in acidic aqueous media on bulk Pt proceeds through a two-steps Volmer–Tafel mechanism. First, the discharge step (Volmer reaction); second, the recombination step (Tafel reaction). While on single Pt atoms, we demonstrated that the HER occurs through a Volmer–Heyrovský mechanism, that is, the rate-determining step is the electrochemical desorption of Hads and H3O+ to form hydrogen (Figure 1). The electrocatalytic activities and mechanism of the hydrogen evolution reaction (HER) and hydrogen oxidation reactions (HOR) will be reported.

Electrochemical Manipulation of Living Cells Supported By Polymeric Nanosheets

Introduction Regenerative medicine based on cell sheets has been widely investigated. Developing an effective and minimally invasive cell transplantation process is an important enabling step for such medical treatments. However, cell sheets are fragile and handling them is difficult. Recently, we have investigated the use of biodegradable polymeric nanosheets for introducing cells into the body and found that the flexible nanosheets on which cells are cultured can be aspirated and injected by a syringe needle without significant loss of cell viability. To harvest cell/nanosheet constructs from a substrate, a water soluble sacrificial layer such as polyvinyl alcohol (PVA) was used, however, a drawback in this method is that the timing to detach the cell/nanosheet constructs from the substrate cannot be controlled. In this paper, we use an electrochemical method for harvesting the cell/nanosheet constructs in vitro. Cells are cultured on nanosheets attached on a self-assembled monolayer (SAM) of alkanethiol. The SAM is reductively desorbed from the gold substrate by the application of a negative electrical potential, which detaches the cell/nanosheet constructs from the gold surface in a rapid manner. The harvested cell/nanosheet constructs were transplanted into the subretinal space of rat eyes through syringe needles. Material and Method A gold layer was patterned by sputter-depositing gold with a patterned silicon mask. The gold surface was modified with 10-carboxy-1-decanethiol, 7-carboxy-1-heptanethiol or L-cysteine by immersing the substrates in any of the three thiol solutions for 30 min at room temperature. The desorption of the SAMs was performed and analyzed electrochemically. Nanosheets were first prepared on PVA-coated substrates by a combination of a spincoating and microcontact printing technique using poly(dimethyl siloxane) (PDMS) stamps. A solution of poly(lactic-co-glycolic acid) (PLGA) was spincoated onto the PDMS stamp and the resulting PLGA layer was transferred onto a PVA-coated substrate. Freestanding nanosheets were obtained by dissolving the PVA sacrificial layer with water and attached on the SAM-modified gold surface. To desorb the nanosheets with SAMs, a voltage of 1.5 V, supplied by an AA-size dry battery, was applied between the gold electrode (cathode) and the Pt wire (anode) in phosphate buffered saline. Retinal pigment epithelium (RPE) cells were cultured on PLGA nanosheets attached on the SAMs for 2 days to form cell/nanosheet constructs. Electrochemical desorption of SAMs with cell/nanosheet constructs was conducted in culture medium. Sprague-Dawley rats (SLC) weighing 250-300 g were used in this study. After the rats were anesthetized with ketamine hydrochloride and xylazine hydrochloride, RPE cell/nanosheet constructs were injected into the subretinal space using a hand-made glass capillary needle. Result and Discussion Cyclic voltammograms observed in the reductive desorption of SAMs showed a clear dependence of peak potential on the length of the alkyl chain. With longer chains, the peak potential shifted to the negative direction, which has been explained by van der Waals interactions between the alkyl chains. Since the SAM of L-cysteine was reductively desorbed at a lower potential (around -0.7 V vs. Ag/AgCl) than the SAM of the two other thiol molecules and L-cysteine is biocompatible, the SAM of L-cysteine was used for harvesting nanosheets and cell/nanosheet constructs. PLGA nanosheets attached on the SAM of L-cysteine were successively detached from the substrate by gently pipetting within 1 min after applying the reductive potential to the gold electrode. On the other hand, nanosheets on the SAM without applying the voltage did not detach from the substrate. In a similar manner, RPE cell/nanosheet constructs could be detached from the substrate and the live/dead staining showed the cells on the nanosheets are viable. Finally, we used our system to deliver RPE cell/nanosheet constructs to the subretinal space of a rat eye in vivo. Nanosheets were injected with 2 μL of saline to the subretinal space through the sclera using a glass capillary needle. Optical coherence tomography (OCT) images of the retina taken one week after the injection of the nanosheets showed a shadow of the sheet like structure in the subrentinal space while there was not such shadow in the OCT image of a control. Also, a shadow of the circular nanosheet was observed at the posterior segment of the isolated eye. These results indicate that the nanosheets were successfully injected and spread into the subretinal space of rat eyes. Conclusion We reported a method for noninvasively harvesting cell/nanosheet constructs from a culture surface by using the electrochemical desorption of SAM. The harvested RPE/nanosheet constructs could be delivered to the subretinal space using a capillary needle. The harvesting and delivering system of cell/nanosheets constructs could be a useful tool for cell transplantation.

Electrocatalytic Processes on PbO2 Electrodes at High Anodic Potentials

The determination of the electrocatalytic activity and selectivity of electrodes with respect to the target process is considered to be of interest both in the theoretical aspect for the development of electrocatalysis theory and in application for efficient electrocatalysts which can be used in electrochemical systems for wastewater treatment. The purpose of the given work was to identify the relationship between the chemical and phase composition of materials based on lead dioxide, their physicochemical properties, and their electrocatalytic activity. The main research methods were quasi-stationary polarization and impedance spectroscopy, photocolorimetry, fluorescent and spectrophotometry in the UV and visible regions, atomic absorption spectroscopy, and high performance liquid chromatography (analysis of the solutions). It was shown that the modification of lead dioxide by ionic additives results in significant changes in the electrocatalytic activity of the system in respect to the oxygen evolution reaction and electrochemical oxidation reactions of organic compounds. It was found that, at low polarizations, the oxygen evolution reaction is limited by the electrochemical desorption step (the second electron transfer), and its overpotential at PbO2-modified electrodes increases in the order that coincides with the dependence in which the number of oxygen-containing particles strongly bound to the electrode surface increases. It was found that the rate of oxidation of organic substances on the anode materials involved is directly proportional to the amount of oxygen-containing radicals formed on the electrode during the water oxidation.

Engineering thick cell sheets by electrochemical desorption of oligopeptides on membrane substrates.

We developed a gold-coated membrane substrate modified with an oligopeptide layer that can be used to grow and subsequently detach a thick cell sheet through an electrochemical reaction. The oligopeptide CCRRGDWLC was designed to contain a cell adhesive domain (RGD) in the center and cysteine residues at both terminals. Cysteine contains a thiol group that forms a gold–thiolate bond on a gold surface. Cells attached to gold-coated membrane substrates via the oligopeptide layer were readily and noninvasively detached by applying a negative electrical potential to cleave the gold–thiolate bond. Because of the effective oxygen supply, fibroblasts vigorously grew on the membrane substrate and the thickness of the cell sheets was ∼60 μm at 14 days of culture, which was 2.9-fold greater than that of cells grown on a conventional culture dish. The cell sheets were detached after 7 min of electrical potential application. Using this approach, five layers of cell sheets were stacked sequentially with thicknesses reaching >200 μm. This approach was also beneficial for rapidly and readily transplanting cell sheets. Grafted cell sheets secreted collagen and remained at the transplanted site for at least 2 months after transplantation. This simple electrochemical cell sheet engineering technology is a promising tool for tissue engineering and regenerative medicine applications.

Electron Transfer Across an Antifouling Mercapto-hepta(ethylene glycol) Self-Assembled Monolayer

Oligo(ethylene glycol) films are known to be very efficient at reducing the nonspecific adsorption of biomacromolecules on surfaces, but they often show a tendency to decrease drastically the rate of heterogeneous electron transfer at the modified surface, making them unsuitable for electrochemical biosensing. In this work, the heterogeneous electron transfer across the self-assembled monolayer of a short thiolated oligo(ethylene glycol) is investigated using four redox systems: [Fe(CN)6]3–/4–, [Ru(NH3)6]3+/2+, Fc(MeOH)2+/0, and [IrCl6]2–/3–. Fast electron-transfer kinetics are evidenced in all cases except the ferri/ferrocyanide couple, for which the electron transfer is completely suppressed. Interfacial characterizations by means of spectroscopic ellipsometry, electrochemical desorption experiments, and capacity measurements indicate that the film consists of a fairly hydrated single monolayer with a surface concentration of 4.1 × 10–10 mol cm–2. The peculiar behavior of [Fe(CN)6]3–/4– is discussed in ...

Fabrication of High‐aspect Ratio (HAR) Palladium Nanorod‐modified Electrodes for Raman Spectroelectrochemical Studies of Thiolate Desorption from HAR Nanomaterials

AbstractWe describe a method to fabricate electrodes modified with high‐aspect ratio (HAR) palladium (Pd) nanorods derived from the electrochemical reduction of Pd salts in polycarbonate track‐etched membranes. The HAR Pd nanorod‐modified electrode platform enables direct spectroscopic observation of electrochemical processes particular to HAR forms of nano‐Pd using Raman spectroelectrochemistry. In the present study, we use this platform to observe an anomalous mechanism of oxidative electrochemical desorption of the probe molecule benzenethiol (BT) from the HAR Pd surface. At HAR Pd, the Pd−S bond between the Pd nanorods and BT severs upon oxidation of the Pd surface, whereas on the surface of spherical nano‐Pd, the C−S bond in BT is broken, as is more typically observed for sulfur‐containing organic molecules adsorbed to Pd surfaces. Using this probe reaction, we demonstrate the suitability of this HAR nanorod‐modified electrode platform for the investigation of anomalous electrochemical phenomena observed at HAR Pd for reactions that involve adsorbed intermediates in general – including not only adsorbed sulfur – but in principle also for the electrochemical oxidation of alternative fuels such as ethanol and methanol.