NaCl-induced nickel–cobalt inverse spinel structure for boosting hydrogen evolution from ethyl acetate and water

Abstract

The proper design of an NaCl-induced nickel–cobalt inverse spinel structure is reported as a promising catalyst for boosting H₂ evolution from the energy benign sources of ethyl acetate and water. The designed NiCo_0.5O_y/NaCl catalyst exhibits the optimal performance with ∼100% EA conversion, 88.1% H₂ selectivity and high stability during autothermal reforming at 650 °C and achieves a very high H₂ selectivity of 96.3% at 600 °C by accelerating the water–gas shifting reaction (the rate-determining step). The multiple (Ni_xCo_1−x)(Ni_yCo_2−y)O₄ inverse spinel structures play significant roles in the enhanced catalytic performance. Benefiting from the unique advantages of (i) stable inverse spinel structures, (ii) abundant domains and defects, (iii) abnormal Ni²⁺/Ni³⁺ (0.36) and Co²⁺/Co³⁺ (3.03) ratios, and (iv) rich redox ability, the catalyst possesses high adsorption capacity towards EA and H₂O, abundant active sites and fast electron exchange ability between the reactants and the catalyst. Consequently, the catalyst exhibits a highly efficient and robust hydrocarbon fuel reforming performance. These findings will lead to the development of novel catalysts based on inverse spinels for hydrogen production applications.