Calcination-Free Synthesis of Porous Metal Oxides/Carbon from Calcium Carbide by Ball Milling

Calcium carbide is a key intermediate in the chemical industry, such as cyanamide industry (>2 Mton year–1 for CaCN2), and in the manufacture of vinyl chloride (∼13 Mton year–1). The environment-friendly utilization of reactive CaC2 is of great interest. Herein, by ball milling CaC2 and equimolar metal chlorides, porous carbon-supported transition-metal oxides were obtained without calcination treatment. This mechanochemical synthesis route was based on the CaC2 replacement reaction and the Cl–-triggered free-radical reaction. Different metal oxides including Mn3O4/C, Fe3O4/C, NiOx/C, Cu2O/C, ZnO/C, ZrO2/C, Nb2O5/C, CeO2/C, HfO2/C, and WO3/C showed high surface areas up to 232 m2g–1. Moreover, the as-made metal oxides displayed good performance in heterogeneous catalysis. NiOx/C promoted selective nitrobenzene hydrogenation with high conversion and selectivity (>99% Conv., >99% Select.), while CuMnCeOx/C achieved 90% CO conversion at 120 °C in CO oxidation.