Theoretical and experimental investigation of ZrO2 incorporated in nickel phosphate matrix for hydrogen production: Catalytic efficiency and electronic properties

This study presents a comprehensive experimental and theoretical evaluation of a Zr/NiP catalyst for hydrogen production via the partial oxidation of ethanol (POE). The catalyst Zr/NiP was prepared by impregnation in liquid phase, and their catalytic tests in POE showed an excellent performance, achieving a hydrogen yield of 83% at 295 °C; thus, it can be attributed to the synergistic interaction between nickel and ZrO${}_2$, which enhances metal dispersion and catalytic stability. Catalytic activity tests performed at elevated temperature demonstrated a high selectivity toward CO${}_2$, with minimal acetaldehyde formation, indicating effective oxidative dehydrogenation and resistance to carbon deposition. Complementary density functional theory calculations confirmed that cubic ZrO${}_2$ has a wide band gap (5.3 eV), with electronic states dominated by O 2p and Zr 4d, which contribute to surface polarization and activate the catalytic sites. Optical studies confirm that ZrO${}_2$ has strong UV absorption, enhancing its photocatalytic efficiency for sustainable hydrogen production.