High-resolution 1H nuclear magnetic resonance study of hydrogen sulphide adsorption on heterogeneous catalysts
Solid-state high-resolution 1H n.m.r. spectra of H2S adsorbed on Al2O3, NaOH/Al2O3, K2CO3/Al2O3, HF/Al2O3, H3PO4/SiO2, K2CO3/SiO2 catalysts and NaX, NaY, H-ZSM-5 zeolites have been studied.
The dissociative H2S adsorption on Al2O3, and Al2O3 modified with KOH, K2CO3 and HF as well as on zeolite catalysts was found as indicated by the lines from SH– species at –1.6 to –2.0 ppm for Al2O3, modified Al2O3 and ZSM-5, and at –3.7 to –4.3 ppm for NaX, NaY zeolites. H2S adsorbed without dissociation, giving a line at 1.2–1.8 ppm, was observed at increased surface coverage. For Al2O3, modified Al2O3, K2CO3/SiO2 and H-ZSM-5 the dissociative adsorption occurred on the coordinatively unsaturated Al sites while Na+ cations in the zeolite cavities of NaX and NaY zeolites are responsible for H2S dissociation. Only physically adsorbed H2S was observed on H3PO4/SiO2 catalyst.