The transformation of Cu(OH)2 into CuO, revisited

Abstract

Copper hydroxide Cu(Off2 is metastable. ft transforms easily into copper oxide CuO more stable, either in the solid state by a thermal dehydration or at room temperature, in aqueous basic solutions. In the solid state the transformation is performed at a relatively low temperature,423 K. It is a topotactic or a pseudo-morphic transformation for the reason that a clear relationship exists between axes of the two solids, in the three directions. The reacting process is described and corresponding vectorial relations between crystal parameters are proposed. It is not the same case in aqueous basic solutions. Copper hydroxide gives rise to oxide through the formation of a complex anion, Cu(OH)+2-, by a reconstructive transformation involving a dissolution reaction followed by a precipitation.

Synthesis of different CuO nanostructures by a new catalytic template method as anode materials for lithium-ion batteries

“…This indicates that the Cu(OH) 2 powder can be converted into CuO at a rather low temperatures. 19 Nevertheless, the peaks in Fig. 3a and b are broad, suggesting that the crystallinity of the as-prepared Cu(OH) 2 and CuO is low.…”

Thermal, solution and reductive decomposition of Cu–Al layered double hydroxides into oxide products

“…The formation of crystalline CuO at much lower temperatures than during thermal decomposition is related to the fact that under these conditions decomposition proceeds via dissolution and reprecipitation. As explained by Cuddenec and co-workers [31], upon dissolution, the Cu 2+ ion adopts a square planar coordination in the complex anion [Cu(OH) 4 ] 2À . This is a precursor to CuO which also has Cu 2+ in square planar coordination.…”

Gram‐Scale Synthesis of Cu2O Nanocubes and Subsequent Oxidation to CuO Hollow Nanostructures for Lithium‐Ion Battery Anode Materials

“…However, the tetrahydroxo-cuprate(II) anion ðCuðOHÞ 2À 4 Þ is likely to be generated from the copper hydroxide under a strong basic environment (reaction 3), because of the Jahn-Teller stabilization in square-planar copper(II) complexes. [19] Eventually, thermodynamically stable CuO is produced and precipitated to yield solid particles (reaction 4), due to its low solubility in water. In this sequential oxidative dissolutionprecipitation mechanism, ammonia and hydroxide concentrations are the main factors for kinetic parameters of the reaction and the resulting particle shapes.…”