Improved biohydrogen production using Ni/ZrxCeyO2 loaded on foam reactor through steam gasification of sewage sludge.

The pervasive generation of sewage sludge (SES) and deficiencies in its disposal methods have resulted in several significant environmental and human health challenges. This study explored the catalytic effect of nickel (Ni)-based CeO₂, ZrO₂, Zr₀.₈Ce₀.₂O₂, Zr₀.₄Ce₀.₆O₂, and γ-Al₂O₃ supports in fixed beds and foam reactors in the steam gasification of SES. A comparison of the hydrogen selectivity and gas yield of the synthesized catalysts confirmed that the metal composite support, especially Zr₀.₈Ce₀.₂O₂, had a positive effect on the catalytic activity and stability. This can be attributed to the enhanced oxygen vacancies and oxygen mobility, resistance to coke deposition, uniform morphology, improved dispersion, and increased number of Ni sites on the Zr₀.₈Ce₀.₂O₂ support. Furthermore, foam reactors offer unique advantages in improving hydrogen production. This study provides an advanced strategy for SES valorization that fulfills the requirements of an economically and environmentally sustainable technology.