Catalytic metal hydroxide nanostructures: aerobic C-H activation and catalytic low temperature carbon monoxide oxidation by NixMn(1-x)(OH)2

Abstract

Metal hydroxides and mixed metal hydroxides have been frequently utilized in diverse applications such as battery technologies, electrocatalysis, electrosynthesis, photocatalysis, supercapacitors, electrochromic devices, and electrochemical sensors. Yet, precious metal-free hydroxides have not been utilized to their full potential in the field of catalytic aerobic C-H activation and catalytic low-temperature CO oxidation. In this work, we demonstrate that upon careful optimization of catalyst synthesis protocols, a novel catalytic architecture is achieved in the form of Ni0.6Mn0.4(OH)2 revealing remarkable catalytic performance in the aerobic oxidation of alkylarenes, particularly in the aerobic oxidation of xanthene to xanthone. This optimized catalyst also shows superior catalytic activity in low-temperature CO (g) oxidation. We also present an efficient catalytic regeneration protocol, which can redeem the full initial activity of the carbon-poisoned spent catalyst in xanthene oxidation. Catalytic functionality of this novel nanomaterial architecture is also examined in detail in light of comprehensive characterization experiments including ATR-IR, XRD, BET-SSA, TGA, TEM, EDX and XPS measurements.