Solid catalysts treated with anions

A dehydrogenation catalyst for alkanes was obtained by immersing Zr(OH)4 in 0.05M (NH4)2CrO4, followed by calcination in air at 600–800°C and reduction at 550°C (0.5 wt.-% Cr). This catalyst converted hexane into benzene with a selectivity of up to 89% under pulse conditions, and the yield of benzene at 550° C was steady up to 6 h with 76% selectivity in a flow system at atmospheric pressure. HfO2 was also effective as a support, but Al2O3, SiO2, TiO2, and SnO2 were not. Measurements of ESR and XPS showed the ZrO2 catalyst to be CrIII-CrIV, created by reduction of CrO42−/ZrO2.