A cell for the controllable thermal treatment and electrochemical characterisation of single crystal alloy electrodes
Graphical abstract
Highlights
► A cell for controllable thermal treatment and electrochemical characterization. ► Annealing and characterisation without exposing samples into the laboratory atmosphere. ► Typical model experiments with Pt(111) single crystal electrodes and sub-surface alloys.
Introduction
The well-established experimental protocol for pretreating metal single crystals involves annealing the crystals before electrochemical characterisation [1], [2]. A heat treatment is necessary to prepare reproducibly well-ordered and clean surfaces [3]. Flame annealing and resistive or inductive heating followed by cooling in a reducing atmosphere are the most common techniques to prepare the single crystal surfaces of Pt, Au, Pd and other noble metals for electrochemical applications [4], [5].
Although the above-mentioned protocol has been used successfully for decades in single crystal electrochemistry, the preparation and characterisation of single crystalline surfaces could be improved even further. The majority of procedures reported in literature assume that single crystals should be transferred into the measurement electrochemical cell through the laboratory atmosphere [1], [2], [3], [4], [5], [6]. Normally, it is done under the protection of the surface by droplets of ultra clean water. However, it would be preferable to avoid this step, and anneal and perform electrochemical measurements in the same cell. This would improve reproducibility and minimise adventitious contamination from the laboratory atmosphere.
Vacuum-based surface science studies have demonstrated that by depositing different metals atop the single crystals and annealing them in the presence of reactive gases, the crystal surfaces can be efficiently tailored. Such thermal treatments are common, for example, to prepare surface alloys (SA) and near-surface alloys (NSA) [7], [8], [9]. However, using the flame annealing technique it is not possible to accurately control temperature over a wide range. This problem can be solved by using the inductive heating (IH) [10] or resistive heating [11] in the same cell. However, to the best of our knowledge, there are no reports describing the IH-temperature control and corresponding cell designs for combined high-temperature preparation, modification and electrochemical characterisation of single crystal surfaces.
In this communication, we describe a new cell, which provides an opportunity to combine electrochemical surface modification, characterisation and controllable thermal treatment. All operations can be performed without exposing the sample into the laboratory atmosphere. We report typical model experiments with Pt(111) single crystal electrodes, including the preparation and basic voltammetric characterisation of Cu/Pt(111) SA and NSA.
Section snippets
Cell design
A schematic drawing of the cell is shown in Fig. 1. It consists of compartments made of either Pyrex™ or quartz glass, an IH, a reference electrode (RE), a counter electrode (CE) and a single crystal working electrode (WE) in a standard hanging meniscus configuration.
The position of the single crystal can be adjusted vertically using a movable shaft; so the crystal can be lifted up and annealed by the inductive heater and always kept in a controllable atmosphere. The shaft provides electrical
Experimental
Before each experiment, the glassware was cleaned in a “piranha” solution consisting of a mixture of 96% H2SO4 and 30% H2O2 (3:1) for 24 h, followed by multiple heating/rinsing with Millipore© water to remove sulphates.
All model experiments described in this manuscript were performed using several Pt(111) single crystals: (a) a small bead-type Pt(111) crystal (oriented to < 0.05°) obtained from Prof. Juan Feliu (University of Alicante, Spain) prepared according to [2], and (b) with diameters of 5
Results and discussion
In the following, we present examples of typical experiments which can be performed using the proposed cell. Fig. 3 compares typical Pt(111)-voltammograms for the crystals annealed using conventional flame annealing of bead-type single crystal (Fig. 3A) and the 5 mm crystal annealed using the method developed in this work (Fig. 3B). Three different regions are distinguishable in the voltammograms shown in Fig. 3. These are associated with hydrogen UPD (between 0.07 V and 0.4 V), the adsorption of
Acknowledgements
We thank Professor J. Feliu from the University of Alicante (Spain) for providing high-quality Pt(111) single crystal. The Center for Individual Nanoparticle Functionality is supported by the Danish National Research Foundation. A.S.B. acknowledges financial support from the European Union and the MWIFT-NRW (Hightech.NRW competition). I.E.L.S. is funded by the Energinet.dk, for the CATBOOSTER project, through the ForskEL R&D programme.
References (20)
- et al.
Journal of Electroanalytical Chemistry
(1986) - et al.
Electrochemistry Communications
(2000) - et al.
Journal of Electroanalytical Chemistry
(1999) - et al.
Electrochemistry Communications
(2011) - et al.
Surface Science
(2001) - et al.
Electrochemistry Communications
(2006) - et al.
Electrochemistry Communications
(2006) - et al.
Electrochemistry Communications
(2005) - et al.
Electrochimica Acta
(2008) - et al.
Electrochemistry Communications
(2007)
Cited by (22)
Evaluation of the Electrochemical Stability of Model Cu-Pt(111) Near-Surface Alloy Catalysts
2015, Electrochimica ActaCitation Excerpt :Our tests reveal at least two counterintuitive effects, which contest the idea that interactions between subsurface Cu and electrolyte-originated oxygenated species would destabilize the system [22,23]: (i) the Cu-Pt(111) NSAs are more stable against anodic degradation compared to Cu-Pt bulk alloys and nanostructured materials reported in the literature; (ii) the voltammetric features for the NSA samples after the stability tests suggest formation of quasi-ordered Pt(111) facets, resulting in a domain structure of the catalyst surface. All experiments were performed at room temperature in the electrochemical cell described in detail elsewhere [24,25]. Two Pt(111) single crystals with a diameter of 5 mm, oriented better than 0.1° (Mateck, Germany), and surface roughness of 30 nm were used as working electrodes to ensure reproducibility.
Influence of the alkali metal cations on the activity of Pt(1 1 1) towards model electrocatalytic reactions in acidic sulfuric media
2015, Catalysis TodayCitation Excerpt :To ensure reproducibility, all experiments were performed using two Pt(1 1 1) single crystals having diameters of 5 mm, surface roughness of 30 nm, and oriented better than 0.1° (Mateck). The preparation and characterization under hanging meniscus configuration prior to each experiment was described in detail [28–30]. An Hg/HgSO4 electrode and a Pt wire (GoodFellow) were used as the reference and counter electrodes, respectively.
Preparation of thin film Cu-Pt(1 1 1) near-surface alloys: One small step towards up-scaling model single crystal surfaces
2013, Electrochimica ActaCitation Excerpt :Experimental protocol for the preparation and electrochemical characterisation of this crystal was similar to those reported elsewhere [19]. All electrochemical experiments were performed in a special electrochemical cell reported in Ref. [20]. AFM images were taken using a NanoWizard 3 AFM controlled by a JPK SPMControl Station III (JPK Instruments, Germany) mounted on a vibration damping table Vario Control Micro 40 (Halcyonics, Germany).
The constant phase element reveals 2D phase transitions in adsorbate layers at the electrode/electrolyte interfaces
2013, Electrochemistry CommunicationsCitation Excerpt :Moreover, our results show promise that parameters of the CPE obtained as a function of the electrode potential can be reasonably used to detect 2D phase transitions and provide an improved insight into interfacial properties increasing the impact of EIS measurements. The electrochemical cell used in this work is described in detail elsewhere [16]. 0.05 M solutions of H2SO4 (Merck, Suprapur) and Pt(111) crystals (Mateck, Germany, 5 mm diameter, oriented better than 0.1°, roughness 30 nm) were used.
Structural and electronic effects in heterogeneous electrocatalysis: Toward a rational design of electrocatalysts
2013, Journal of CatalysisCitation Excerpt :Therefore, UPD is a surface limited process where the surface coverage of (metal) adatoms can be precisely controlled by varying the electrode potential. Recently, various UPD-assisted synthetic schemes have gained popularity, as it is a robust and cheap method to tailor the surface structure and composition very accurately [98–109]. On the other hand, capitalizing upon the knowledge obtained from UHV surface science, the position of the electrochemically deposited atomic layers can be controlled using annealing in specific atmospheres (Fig. 9B).
Modeling Temperature-, Humidity-, and Material-Dependent Kinetics of the Oxygen Reduction Reaction
2022, Journal of the Electrochemical Society