Abstract

The present study reports the catalytic action of two-dimensional (2D) layered materials (MoS₂ and WS₂) for improving the de/re-hydrogenation kinetics of MgH2. The MgH₂ start desorbing at 277 ºC with a hydrogen storage capacity of 5.95 wt% in the presence of WS₂ catalyst whereas onset desorption temperature of MgH₂ catalyzed by MoS₂ is 330 ºC. The MgH₂-WS₂ absorbed hydrogen ~ 3.72 wt% within 1.3 minutes at 300 ºC under 13 atm hydrogen pressure and it desorbed ~5.57 wt% within 20 minutes at 300 ºC under 1 atm hydrogen pressure. We have performed 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 ºC) and re-hydrogenation (under 13 atm hydrogen pressure at 300 °C) to ensure cyclic stability of catalyzed version of MgH₂ where MgH₂-WS₂ shows better cyclic stability than MgH₂-MoS2. MgH₂-WS₂ also shows the lower reaction activation energy ~117 kJ/mol as compare to other catalyzed and uncatalyzed samples. On the other hand, these catalysts (WS₂ and MoS₂) do not have any impact on the thermodynamical parameters that is change in enthalpy.

Abstract

The present study reports the catalytic action of two-dimensional (2D) layered materials (MoS₂ and WS₂) for improving the de/re-hydrogenation kinetics of MgH2. The MgH₂ start desorbing at 277 ºC with a hydrogen storage capacity of 5.95 wt% in the presence of WS₂ catalyst whereas onset desorption temperature of MgH₂ catalyzed by MoS₂ is 330 ºC. The MgH₂-WS₂ absorbed hydrogen ~ 3.72 wt% within 1.3 minutes at 300 ºC under 13 atm hydrogen pressure and it desorbed ~5.57 wt% within 20 minutes at 300 ºC under 1 atm hydrogen pressure. We have performed 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 ºC) and re-hydrogenation (under 13 atm hydrogen pressure at 300 °C) to ensure cyclic stability of catalyzed version of MgH₂ where MgH₂-WS₂ shows better cyclic stability than MgH₂-MoS2. MgH₂-WS₂ also shows the lower reaction activation energy ~117 kJ/mol as compare to other catalyzed and uncatalyzed samples. On the other hand, these catalysts (WS₂ and MoS₂) do not have any impact on the thermodynamical parameters that is change in enthalpy.

Abstract

The present study reports the catalytic action of two-dimensional (2D) layered materials (MoS₂ and WS₂) for improving the de/re-hydrogenation kinetics of MgH2. The MgH₂ start desorbing at 277 ºC with a hydrogen storage capacity of 5.95 wt% in the presence of WS₂ catalyst whereas onset desorption temperature of MgH₂ catalyzed by MoS₂ is 330 ºC. The MgH₂-WS₂ absorbed hydrogen ~ 3.72 wt% within 1.3 minutes at 300 ºC under 13 atm hydrogen pressure and it desorbed ~5.57 wt% within 20 minutes at 300 ºC under 1 atm hydrogen pressure. We have performed 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 ºC) and re-hydrogenation (under 13 atm hydrogen pressure at 300 °C) to ensure cyclic stability of catalyzed version of MgH₂ where MgH₂-WS₂ shows better cyclic stability than MgH₂-MoS2. MgH₂-WS₂ also shows the lower reaction activation energy ~117 kJ/mol as compare to other catalyzed and uncatalyzed samples. On the other hand, these catalysts (WS₂ and MoS₂) do not have any impact on the thermodynamical parameters that is change in enthalpy.

Abstract

The present study reports the catalytic action of two-dimensional (2D) layered materials (MoS₂ and WS₂) for improving the de/re-hydrogenation kinetics of MgH2. The MgH₂ start desorbing at 277 ºC with a hydrogen storage capacity of 5.95 wt% in the presence of WS₂ catalyst whereas onset desorption temperature of MgH₂ catalyzed by MoS₂ is 330 ºC. The MgH₂-WS₂ absorbed hydrogen ~ 3.72 wt% within 1.3 minutes at 300 ºC under 13 atm hydrogen pressure and it desorbed ~5.57 wt% within 20 minutes at 300 ºC under 1 atm hydrogen pressure. We have performed 25 cycles of dehydrogenation (under 1 atm hydrogen pressure at 300 ºC) and re-hydrogenation (under 13 atm hydrogen pressure at 300 °C) to ensure cyclic stability of catalyzed version of MgH₂ where MgH₂-WS₂ shows better cyclic stability than MgH₂-MoS2. MgH₂-WS₂ also shows the lower reaction activation energy ~117 kJ/mol as compare to other catalyzed and uncatalyzed samples. On the other hand, these catalysts (WS₂ and MoS₂) do not have any impact on the thermodynamical parameters that is change in enthalpy.