Highly efficient H2 and S production from H2S decomposition via microwave catalysis over a family of TiO2 modified MoxC microwave catalysts

Abstract

Highly efficient H2 and S production from copious waste H2S is beneficial from both environmental and energy. Whereas, the highly effective direct decomposition of H2S reaction faces a gigantic obstacle, that is, there is the severe thermal equilibrium limitation. Herein, a family of TiO2 modified MoxC as novel microwave catalysts have been developed. This work demonstrates that Mo2C, Mo2C-TiO2 and MoC@TiO2 microwave catalysts display excellent catalytic performance to recover both valuable H2 and elemental S from the direct decomposition of H2S under microwave irradiation. The optimal H2S conversion of MoC@TiO2 can be as high as 99.9% (almost complete conversion) at 700 °C, which greatly outpaces the corresponding H2S equilibrium conversion under microwave irradiation. This result of the chemical equilibrium limitation being broken shows an interesting phenomenon, namely a significant microwave selective catalytic effect by microwave catalysis in H2S decomposition reaction. In addition, the apparent activation energy of the Mo2C, Mo2C-TiO2 and MoC@TiO2 microwave catalysts reduced to 18.2 kJ/mol, 16.8 kJ/mol and 15.6 kJ/mol under microwave irradiation. The work supplies a strategy for highly effective valuable H2 and S production from H2S decomposition reaction, and paves a path to high-value utilization of hazardous waste H2S resources with energy-saving heating method.