Ni-modulated MoS2@TiO2 catalyst enhances coal tar hydro-upgrading efficiency

Background Existing molybdenum-based catalysts exhibit unsatisfactory performance in coal tar hydro-upgrading due to limited active sites and weak cracking capability. Methods Supported NiMoS x @TiO 2 catalysts with a tunable Ni/Mo atomic ratio were prepared via a two-step method and applied in coal tar hydrogenation. Findings Importantly, Ni shows dual regulation over MoS 2 formation. With Ni/Mo ≈ 0.1, Ni promotes the conversion of Mo 7 S x O (21− x ) intermediates to highly dispersed, truncated MoS 2 slabs (1–2 layers, 3–8 nm), enhancing nucleation while suppressing stacking and achieving a 64.99 % gasoline and diesel yield. When Ni/Mo ≥ 0.3, excess Ni consumes sulfide to form NiS x and occupies TiO 2 anchoring sites, hindering MoS 2 growth and driving slab fusion into thicker aggregates (4–8 layers, 20–40 nm) that bury edges. This study reveals Ni’s dual-regulation mechanism on MoS 2 nucleation and layer-number evolution, which governs edge-site exposure and dictates coal-tar hydro-upgrading performance.