Non thermal plasma assisted water-gas shift reactions under mild conditions: state of the art and a future perspective

The water gas shift (WGS) reaction is important for many industrial processes such as ammonia synthesis, oil refining and fuel cells. WGS reaction is exothermic and limited by kinetics and chemical equilibrium, and under conventional thermocatalytic conditions, the desired thermodynamic equilibrium conversion and sufficiently fast kinetics can rarely be achieved simultaneously. To address such limitations, non-thermal plasma (NTP) processes have been recently proposed to enhance the kinetics at low temperatures (via gas phase activation), and realising favourable thermodynamic conversion. Here, a critical review of the relevant state-of-the-art regarding NTP-assisted WGS reactions (including both catalytic and non-catalytic systems) is presented. In addition, it also evaluates the concept of reaction-separation integration using novel membrane reactors to improve WGS reaction by shifting reaction equilibrium to favour hydrogen production. Finally, the prospect regarding future research avenues in advancing the NTP-assisted WGS processes is shared.