Tri-metallic Ni–Co modified reducible TiO₂ nanocomposite for boosting H₂ production through steam reforming of phenol

Well-designed Co₃O₄ nanocubes (NCs) dispersed NiO/TiO₂ to construct tri-metallic reducible NiO/TiO₂/Co₃O₄ NCs structured catalyst for steam-reforming of phenol (SRP) with enhanced hydrogen production has been investigated. The controlled morphology with good dispersion was obtained, enabling efficient SRP toward selective H₂ production. Using 10% NiO- 5% Co₃O₄ NCs/TiO₂ composite, H₂ yield of 69.91% and phenol conversion of 78.4% was achieved, significantly higher than using NiO/TiO₂ and TiO₂ samples. The cubical structured Co₃O₄ dispersed NiO/TiO₂ composite showed significantly improved H₂ yield and phenol conversion due to strong metal-support interaction with reducible support for providing more active sites. The H₂ production was further increased by increasing reaction temperature, phenol concentration, feed flow rate and catalysts loading, however, they have adverse effect on the selectivity due to more CO formation. The composite catalyst possesses excellent activity and stability due to strong tri-metallic interaction and exceptional electronic interfaces. The spent catalyst analysis confirms the formation of graphene and carbon nanotubes over the reducible support. This study reveals that Co₃O₄ NCs are able to increase NiO/TiO₂ activity for H₂ production by inhibiting carbon monoxide formation and would be beneficial in other reforming applications.