A core-shell NiCu@NiCuOOH 3D electrode induced by surface electrochemical reconstruction for the ammonia oxidation reaction

Synergistic Effects of Ni and Cu in Morphology-Controlled NiCu Electrocatalysts for Ammonia Electro-oxidation

“…The group observed a substantial current improvement of more than 8 times after the introduction of copper (Cu) to a Ni system compared with bare Ni. This finding was supported by other studies using various Ni alloys, , oxyhydroxide, ,, and chalcogenides. ,, To the best of our knowledge, Cu is the only metal that effectively boosts the AOR activity of Ni, while others have demonstrated almost no effect. These phenomena have prompted researchers to investigate the responsible mechanism, as it may provide a valuable understanding of AOR and pave the way for the synthesis of highly active electrocatalysts.…”

“…21 The group observed a substantial current improvement of more than 8 times after the introduction of copper (Cu) to a Ni system compared with bare Ni. This finding was supported by other studies using various Ni alloys, 22,23 oxyhydroxide, 12,15,24 and chalcogenides. 4,15,19 To the best of our knowledge, Cu is the only metal that effectively boosts the AOR activity of Ni, while others have demonstrated almost no effect.…”

Local tensile strain boosts the electrocatalytic ammonia oxidation reaction

“…However, they generally suffer from high overpotentials (above 1.3 V), low current densities (o 150 mA cm À2 at 0.7 V vs. Hg/HgO), and many by-products (e.g., NO 3 À , NO 2 À , and O 2 ). 4,[10][11][12][13][14][15][16][17][18][19][20][21] A mechanistic understanding of the EAOR is vitally important for the development of high-performance EAOR catalysts. However, studies on the Ni-based EAOR catalysts often employ doping, 4,10,11 alloying, 13,14 and nano-hybrid methods, [15][16][17] which involve complicated compositions and structures coupled with surface reconstruction and/or corrosion, and are not conducive to the clarification of the reaction mechanism.…”

“…4,[10][11][12][13][14][15][16][17][18][19][20][21] A mechanistic understanding of the EAOR is vitally important for the development of high-performance EAOR catalysts. However, studies on the Ni-based EAOR catalysts often employ doping, 4,10,11 alloying, 13,14 and nano-hybrid methods, [15][16][17] which involve complicated compositions and structures coupled with surface reconstruction and/or corrosion, and are not conducive to the clarification of the reaction mechanism. Recently, we reported a simple binary system consisting of Ag and Ni metal powders as a good model for the mechanistic study of the EAOR.…”

“…Previous studies have revealed that Ni 3+ is the active center of the EAOR. 10,16,21,22 As Ni 2+ presents a single Raman peak in the range of 200-800 cm À1 and Ni 3+ shows two typical characteristic Raman peaks at 473 and 554 cm À1 , 28 we carried out in situ Raman spectroscopy to detect the valence change of Ni in the as-prepared catalysts dependent on potential in order to clarify the strain effects on the EAOR. As shown in Fig.…”