Transition metal doped*** electrocatalysts are commonly used in acid oxygen evolution (OER). However, most transition metal oxides are unstable under acidic OER conditions, questioning the true active site of the electrocatalyst surface. In this study, the activity of rumnox increased by more than 30% after time current activation measurements (at 17 v). When the chronometric current measurement potential is less than 1At 1 V, activity is increased. Combining electrochemical measurements with MN dissolution and RU redeposition studies, we verified that the reconstitution of the catalyst is responsible for the activation of electrochemical activity. In addition, the researchers also found that at a current density of 10 mA2, activated Rumnox has 0The potential growth rate of 027 mV h can be used continuously for 2600 h.
a) Raw and 0Electrocatalytic OER performance of 8 V post-treatment RUMNOX. (B) Overpotential evolution of post-treated rumnox at 10 mA2. (c) Post-rumnox Tafel evolution. (d) 0.The CP curve of 8 V post-treatment of Rumnox increased by 70 mV potential by more than 2,600 h at 10 mA cm2. (e) Evolution of post-RUMNOX EDLC.
a) in 14 v、1.1 v、0.8 V and 0At 5 V, Ru and Mn of Rumnox dissolve. The dissolution conditions were deduced from the ion concentration in the electrolyte using ICP measurement. (b) Raman spectra of a series of post-rumnox. The operando-Raman spectra were acquired during chronocurrent electrolysis, and the potential decreased from bottom to top. Use a three-electrode cell (scheme S1) for the operando-raman test. (c) original and (d) 08 V post-processing HRTEM images of Rumnox. (e) Atomic ratio of Ru to Mn in the electrocatalyst.
A) Mn2P and (B) Mn3S XPS spectra of raw and post-processed Rumnox. (c) Xps analysis between MN4+ and Mn3+ and δe. (D) O1S xps spectra of raw and post-rumnox. (With 284.)The C1S peak position of 8 EV was spectrally indexed for non-scaled carbon).
a) Experimental setup involving near-rue redeposition and proposed reconstruction mechanism. The green rectangle indicates the volume of the catalyst, and the blue and yellow circles indicate the RU and MN atoms on the surface. Under the conditions of (b) with stirring, (d) without stirring, and (e) with stirring for 60min, 1Electrocatalytic OER performance of Rumnox at 1 V. (c) Effect of different stirring conditions on activity growth rate: black line (b), blue line (d), red line (e).
Schematic diagram of the surface reconstruction mechanism.
In conclusion, the dynamic reconstruction of rumnox was discovered by chronocurrent electrolysis. When the applied potential is less than 1At 1 V, activation occurs. During the dissolution-redeposition of the active electrocatalyst, MN is transferred to soluble Mn2+ and dissolved RUs are redeposited on the surface. The reconstitution changes the local structure of Rumnox, resulting in more hydroxyl groups adsorbed on the surface, favoring OER under acidic conditions. Activated Rumnox also showed competitive durability, stable for 2,600 h in a 10 mA cm-1 CP test. This study shows that appropriate activation measures can modulate the reconstitution of surface atoms through dissolution and deposition, leading to the activation of electrocatalysts.
reconstructed rumnox with enhanced performance in acidic water oxidation - sciencedirect