Exploring N-Containing Compound Catalyst for H2S Selective Oxidation: Case Study of TaON and Ta3N5

Abstract

In addition to traditional metal oxides, N-containing compound would become efficient catalyst for H2S selective oxidation. TaON and Ta3N5, taking as examples, with porous structure are able to selectively oxidize H2S into sulfur. TaON exhibits ca. 99% H2S conversion and ca. 89% sulfur selectivity at 250 ℃, while Ta3N5 exhibits near complete H2S conversion (~ 100%) and 86% sulfur selectivity at 250 ℃. TaON of lower N content shows higher sulfur selectivity (~ 90–100%) above 130 ℃, compared with that (~ 86–95%) over Ta3N5. Whereas, Ta3N5 of higher N content demonstrates higher H2S conversion (~ 30–40%) below 160 ℃, compared with that (~ 6–30%) over TaON. Temperature programmed desorption results show that Ta3N5 owns larger amount of acid sites and weaker basic sites than TaON. Over Ta3N5, the reactant molecules could dissociatively adsorb on acid sites more frequently and could be easier to move across the weaker basic sites, thus increasing probability for reaction at low temperature. Manipulating both cations and anions in N-containing compound can alter surface property for optimization of selective H2S oxidation.