Steam-driven Crystalline-Amorphous Coupling Design of Homogenous Metal Hydroxides for Oxygen Evolution Reaction

The crystalline-amorphous (c-a) structure is emerging as a promising design of oxygen evolution electrocatalysts. However, homogenous compositions and excellent stability are hindering further industrial applications. Only by using metal nitrates and methanol solvent, we provide an effective steam-driven strategy to directly fabricate c-a electrocatalysts. The division of methanol molecules establishes an experimental approach to analyze the targeted transformation from crystalline to c-a phase for monometallic nickel hydroxy-nitrates. Following, this design is successfully extended to the bimetallic NiFe layered double hydroxide (NiFe-LDH). The presence of Fe3+ not only effectively promotes electrochemical activity but also enhances adhesion to the nickel foam, conjuring up an ultra-active and ultra-stable NiFeA-S@NF electrocatalyst with an overpotential of 205 mV at 10 mA cm-2 and excellent 200 h stability at 500-1000 mA cm-2. In light of the above findings and preliminary scale-up experiment, this approach offers both fundamental and practical guidelines for other non-noble-metal-based electrocatalysts.