Structural Inheritance and Redox Performance of Nanoporous Electrodes from Nanocrystalline Fe85.2B10-14P0-4Cu0.8 Alloys

Abstract

Nanoporous electrodes have been fabricated by selectively dissolving the less noble α-Fe crystalline phase from nanocrystalline Fe85.2B14–xPxCu0.8 alloys (x= 0, 2, 4 at.%). The preferential dissolution is triggered by the weaker electrochemical stability of α-Fe nanocrystals than amorphous phase. The final nanoporous structure is mainly composed of amorphous residual phase and minor undissolved α-Fe crystals and can be predicted from initial microstructure of nanocrystalline precursor alloys. The structural inheritance is proved by the similarity of the size and outlines between nanopores formed after dealloying in 0.1 M H2SO4 and α-Fe nanocrystals precipitated after annealing of amorphous Fe85.2B14−xPxCu0.8 (x = 0, 2, 4 at.%) alloys. The Redox peak current density of the nanoporous electrodes obtained from nanocrystalline Fe85.2B10P4Cu0.8 alloys is more than one order higher than those of Fe plate electrode and its counterpart nanocrystalline alloys due to the large surface area and nearly-amorphous nature of ligaments.

Enhanced Azo-Dyes Degradation Performance of Fe-Si-B-P Nanoporous Architecture

“…Thus, α-Fe grains own the highest electrochemical activity among α-Fe, Fe 2 B, Fe 3 P and residual amorphous phases (confirmed by XRD and SADPs in Figure 1 and Figure 3) and undergo the preferential dissolution of α-Fe grains in 0.05 M H 2 SO 4 solution. The selective dissolution behavior of α-Fe grains in annealed Fe 76 Si 9 B 10 P 5 alloy is similar to the reported mechanism although the present reactions are more complicated due to the involvement of other Fe 2 B and Fe 3 P phases [23,24]. In other words, α-Fe grains dissolved quickly once exposed to H 2 SO 4 solution, while the residual amorphous phases, Fe 2 B and Fe 3 P, with higher corrosion potentials, dissolve slowly, as shown in the results presented in Figure 3 and Figure 4.…”

“…During the process of dealloying in 0.05 M H 2 SO 4 solution, a nanoporous structure formed because of the partially preferential dissolution of α-Fe phase. In our previous research [23,24], α-Fe grains in nanocrystalline Fe 83.3 Si 3 B 10 P 3 Cu 0.7 and Fe 85.2 B 10–14 P 0–4 Cu 0.8 alloys are preferentially dissolved in the form of micro-coupling cells between anodic α-Fe grains and cathodic residual amorphous phases. In this research, active dissolution of high-purity Fe plate, Fe 85 B 15 alloy, Fe 3 P alloy, and as-spun Fe 76 Si 9 B 10 P 5 amorphous alloy in Figure 4 to some extent reflects the active dissolution of α-Fe, Fe 2 B and Fe 3 P phases in the matrix of the annealed Fe 76 Si 9 B 10 P 5 precursor alloys during dealloying.…”

Formation of micro/nano pits with high catalytic activity on Fe80B20 amorphous alloy

“…Dan et al annealed a Cu-containing Fe-based amorphous alloy and achieved a composite alloy composed of nanocrystalline -Fe particles and an amorphous Fe-based matrix. They further applied dealloying on the composite precursor selectively leached the crystalline -Fe phase from the more stable amorphous matrix, resulting in a porous amorphous structure [13]. Although porous surfaces can be obtained by the above methods, the precursor alloys require either a complex composition design or precise control of devitrification, besides tuning the corrosion process.…”

Controlling the Mechanical Properties of Bulk Metallic Glasses by Superficial Dealloyed Layer

“…The cylindrical specimens were machined into 4 mm in height and then polished. The dealloying technique [ 25 , 26 , 27 ] was performed in 0.05 M HF aqueous solution at room temperature (RT, ~298 K) with the duration ranging from one day to 5 days. Meanwhile, three NPC/BMG composite rods prepared with dealloying time t = 1, 3, and 5 days, is labeled as NPC/BMG rod 1, 2, and 3, respectively.…”