High throughput screening of localised and general corrosion in type 2205 duplex stainless steel at ambient temperature

Bipolar electrochemistry is used to produce a linear potential gradient across a bipolar electrode(BPE),providing direct access to the anodic and cathodic reactions under a wide range of applied potentials.The occurrence of pitting corrosion,crevice corrosion,and general corrosion on type 2205 duplex stainless steel(DSS 2205)BPE has been observed at room temperature.The critical pit depth of 10-20μm with a55%-75% probability of pits developing into stable pits at potential from+0.9 to+1.2 V vs.OCP(open circuit potential)are measured.All pit nucleation sites are either within ferritic grains or at the interface between austenite and ferrite.The critical conditions for pitting and crevice corrosion are discussed with Epit(critical pitting potential)and Ecre(critical crevice potential)decreasing from 0.87 and 0.80 V vs.OCP after150 s of exposure to 0.84 and 0.76 V vs.OCP after 900 s of exposure,respectively.Pit growth kinetics under different applied bipolar potentials and exposure times have been obtained.The ferrite is shown to be more susceptible to general dissolution.

Effect of placement angles on wireless electrocoagulation for bipolar aluminum electrodes

We in our previous study reported the wireless electrocoagulation （WEC） based on bipolar electrochemistry for water purification. One of the most important advantages of WEC is the omission of ohmic connection between bipolar electrode （BPE） and power supply, and thus the electrochemical reactions on BPE are driven by electric field in solution induced by driving electrodes. In this study, the impact of placement angle of bipolar aluminum electrode on WEC was investigated to provide a detailed analysis on the correlations between the bipolar electrode placement angle and bipolar electrocoagulation reactions. The results showed that the WEC cell with a horizontal BPE placed at 0° produced the maximum dissolved aluminum coagulant, accounting for 71.6% higher than that with a vertical one placed at 90°. Moreover, the finite element simulations of current and potential distribution were carried out along the surface of BPE at different placement angles, revealing the mechanism of different BPE placement angles on aluminum dissolution rates in WEC system.

Visual Voltammogram at an Array of Closed Bipolar Electrodes in a Ladder Configuration

In this paper,we report a method for obtaining a visual voltammogram at a linear array of closed wireless bipolar electrodes(BPEs).This advancement is significant,because the visual voltammogram captures the entire current-potential(i-E)relationship of a faradaic reaction in one image and is continuously generated over time.Therefore,we anticipate that this method will allow monitoring in redox systems that change over time.Further,the use of a linear array of BPEs eliminates the need to use a potentiostat and can be carried out with a simple DC power supply.Our experimental and numerical results demonstrate that the visual voltammogram is similar to a linear sweep voltammogram and therefore,information about the faradaic process can be extracted from the wave position,height,and shape.

Fabrication of luminescent patterns using aggregation-induced emission molecules by an electrolytic micelle disruption approach

Herein,we report an electrochemical strategy that could control the location of aggregation-induced emission(AIE)molecules on patterned electrodes in a precise and facile way,producing photoluminescent and electrochemiluminescent patterns with a variety of colors.A micelle composed of electroactive surfactants was broken during the electrooxidation process,in which AIE molecules inside these micelles were released on patterned electrodes.These patterned electrodes were pretreated by not only metal,but also multifarious conducting polymers(CPs).An in-depth investigation clarified a correlation between the variety of CPs used as electrodes and the oxidation rate of the electroactive surfactant due to different catalytic performances of CPs.Furthermore,combined with wireless and gradient features of bipolar electrochemistry,a gradient luminescent pattern was easily achieved.The current studies suggest more abundant luminescent patterns using AIE luminophores can be developed by such an electrochemical method,in both of graphical shapes and emitting colors.