Water enhanced methanol decomposition for simultaneous heat recovery and ready-to-use synthesis gas production over CO2 capture enhanced Ni/zeolite 4A catalyst

Abstract

Methanol decomposition is considered as a “one stone two birds” approach for simultaneously recovering waste heat and affording synthesis gas . However, this approach requires efficient catalysts with high CO selectivity and low selectivity to byproducts. Herein, a rational design of CO 2 capture enhanced Ni/zeolite 4 A catalyst for synthesis gas production by water enhanced methanol decomposition is reported. 5%-Ni/NaA-500 catalyst achieves the Y H2 of 80.6%, Y CO of 76.2%, H 2 /CO molar ratio of 2.11, high stability, low selectivity to CO 2 and CH 4 , and no coke at 325 °C. Ni atoms highly disperse on the surface and microporous of zeolite 4 A, and the strong interaction between Ni atoms and zeolite 4 A inhibits the reduction of Ni atoms. Consequently, Ni 3+ , Ni 2+ and Ni 0 coexist in 5%-Ni/NaA-500, and the redox couples of Ni 3+ ↔Ni 2+ , Ni 2+ ↔Ni 0 , and Ni 3+ ↔Ni 0 will enhance the redox processes during methanol decomposition. CO 2 capture capacity of x %-Ni/NaA-Y below 350 °C promotes the reverse water gas shift reaction by concentrating CO 2 molecules, which hence increases CO selectivity and declines the selectivity to byproducts. The reaction path follows CH 3 OH→CH 3 O→CH 2 O→CHO→CO. This work will pave the way to industrial applications that combine ready-to-use synthesis gas production and heat recovery.