Barium-Promoted Yttria–Zirconia-Supported Ni Catalyst for Hydrogen Production via the Dry Reforming of Methane: Role of Barium in the Phase Stabilization of Cubic ZrO(2)

[Image: see text] Developing cost-effective nonprecious active metal-based catalysts for syngas (H(2)/CO) production via the dry reforming of methane (DRM) for industrial applications has remained a challenge. Herein, we utilized a facile and scalable mechanochemical method to develop Ba-promoted (1–5 wt %) zirconia and yttria–zirconia-supported Ni-based DRM catalysts. BET surface area and porosity measurements, infrared, ultraviolet–visible, and Raman spectroscopy, transmission electron microscopy, and temperature-programmed cyclic (reduction–oxidation–reduction) experiments were performed to characterize and elucidate the catalytic performance of the synthesized materials. Among different catalysts tested, the inferior catalytic performance of 5Ni/Zr was attributed to the unstable monoclinic ZrO(2) support and weakly interacting NiO species whereas the 5Ni/YZr system performed better because of the stable cubic ZrO(2) phase and stronger metal–support interaction. It is established that the addition of Ba to the catalysts improves the oxygen-endowing capacity and stabilization of the cubic ZrO(2) and BaZrO(3) phases. Among the Ba-promoted catalysts, owing to the optimal active metal particle size and excess ionic CO(3)(2–) species, the 5Ni4Ba/YZr catalyst demonstrated a high, stable H(2) yield (i.e., 79% with a 0.94 H(2)/CO ratio) for up to 7 h of time on stream. The 5Ni4Ba/YZr catalyst had the highest H(2) formation rate, 1.14 mol g(–1) h(–1) and lowest apparent activation energy, 20.07 kJ/mol, among all zirconia-supported Ni catalyst systems.