Adsorption microcalorimetric study of rutile and silica-coated rutile

摘要: Abstract A microcalorimeter with two Tian-Calvet thermopiles was used for the determination at 77.4°K of differential energies adsorption argon and nitrogen on pure rutile samples coated different amounts dense silica (0.6, 0.9, 2.6 wt% silica). With each adsorbent, measurements were made after outgassing temperatures 150, 250, 400°C. All plots energy adsorption, Δ a U , against surface coverage, θ, reveal energetic heterogeneity: largest variation given by N 2 outgassed 250 or 400°C smallest silica-coated samples. The -cation interaction provided an appreciable contribution to low coverage when out-gassed 400°C, but not 150°C. Coating 0.6 SiO sufficient block cationic sites deposition 0.9 properties coated-rutile became more like those than rutile.