Integrating Catalysis of Methane Decomposition and Electrocatalytic Hydrogen Evolution with Ni/CeO2 for Improved Hydrogen Production Efficiency.

Ni/CeO2 enables either methane decomposition or water electrolysis for pure hydrogen production. Ni/CeO2, prepared by a sol-gel method with only one heat treatment step, was used to catalyze methane decomposition for the generation of H-2. The solid byproduct, Ni/CeO2/carbon nanotube (CNT), was further employed as an electrocatalyst in the hydrogen evolution reaction (HER) for H-2 production. The Ni/CeO2 catalyst exhibits excellent activity for methane decomposition because CeO2 prevents carbon encapsulation of Ni nanoparticles during the preparation process and forms a special metal-support interface with Ni. The derived CNTs act as antenna to improve conductivity and promote the dispersion of agglomerated Ni/CeO2. In addition, they provide H-2 diffusion paths and prevent Ni/CeO2 from peeling off the HER electrode. Although long-term methane decomposition reduces the HER activity of Ni/CeO2/CNTs (owing to degradation of the delicate Ni/CeO2 interface), the tunable nature of the synthesis makes this an attractive sustainable approach to synthesize future high-performance materials.