Ball milling transformed electroplating sludges with different components to spinels for stable electrocatalytic ammonia production under ambient conditions

Repurposing Mining and Metallurgical Waste as Electroactive Materials for Advanced Energy Applications: Advances and Perspectives

“…The reason should be the high amounts of Fe, Mg dopants, as well as the rich oxygen vacancy in the sludge-derived catalyst. In another study, four electroplating sludge samples have been used to synthesize ZnCr 2 O 4 , CuCr 2 O 4 , and NiCr 2 O 4 catalysts for N 2 reduction [98]. Among the three catalysts, CuCr 2 O 4 shows a higher NH 3 yield of 8.86 µg•h −1 •mg −1 cat (−0.9 V vs. RHE), with an FE of 0.57%.…”

In Situ Grown (Fe,Mn,Ga)3O4–x Spinel/(Mn,Fe)2O3–y Bixbyite Dual-Phase Electrocatalyst for Preeminent Nitrogen Reduction to Ammonia: A Step toward the NH3 Economy

“…M I M 2 II O 4 -type spinel oxides have been investigated as materials for eNRR due to their particular compositional and structural flexibility, catalytic activity, and stability. − Mixed iron manganese oxides for their earth abundance, high electrical conductivity, low toxicity, magnetic properties, and ease of preparation have been synthesized in several structures (i.e., perovskite, spinel, bixbyite, mixed oxide composites), and morphologies . Bixbyite-type Mn 2 O 3 structure is stabilized by large cations like Jahn–Teller Mn­(III) .…”