Ni-Promoted Fe<sub>2</sub>O<sub>3</sub>/Al<sub>2</sub>O<sub>3</sub> for Enhanced Hydrogen Production via Chemical Looping Methane Reforming
Yanxin Yang, Yu Qiu, Zhenwu Zhang, Sheng Wang, Hui Chen, Dewang Zeng, Rui Xiao
Abstract
Chemical looping methane steam reforming shows promise for hydrogen production due to in situ CO 2 capture and inherent hydrogen production but is limited by the low reactivity of the oxygen carriers. In this work, we propose several Ni-promoted Fe 2 O 3 /Al 2 O 3 to generate hydrogen via chemical looping methane reforming and investigated the origin for the promoted redox performance; 10 wt % NiO–Fe 2 O 3 /Al 2 O 3 shows high CH 4 conversion (96%), H 2 yield (3.3 mmol/g), and low carbon deposition (0.093 mmol/g). DFT calculations demonstrate that metallic Ni can decrease the energy barriers (1.24 eV) for methane activation. Characterizations manifest that 10 wt % NiO–Fe 2 O 3 /Al 2 O 3 can significantly increase the reduction depth of Fe 2 O 3, thus providing more oxygen vacancies for hydrogen production. A further increase in Ni content would decrease the oxygen capacity, reducing the potential for hydrogen production. Therefore, the enhanced redox performance of 10 wt % NiO–Fe 2 O 3 /Al 2 O 3 results from the ability of Ni to facilitate CH 4 activation, improving the reduction of Fe 2 O 3 without significantly improving carbon deposition. We anticipate that the synergy between Ni and Fe 2 O 3 can lead to the development of highly active and stable oxygen carriers.