Growth characteristics and methanation behaviors of Ni/SiO2 nanocatalysts prepared by fluidized bed atomic layer deposition

CO 2 methanation via Ni/SiO 2 catalysts is an attractive method of converting CO 2 and storing renewable energy, where the Ni particle size and dispersion are decisive factors governing activity, selectivity, and durability. Here, fluidized bed atomic layer deposition (FB-ALD) was used to construct size-controlled and well-dispersed Ni nanoparticles on SiO 2 sub-microparticles for CO 2 methanation. The growth characteristics and properties of Ni nanoparticles with different ALD cycles and the methanation behaviors of Ni/SiO 2 catalysts were investigated. The results showed that adjusting the number of ALD cycles enabled precise control of both the Ni loading (2.1–6.6 wt%) and the particle size (1.2–3.0 nm) in the FB-ALD process, while ensuring uniform dispersion on the SiO 2 support. The 60ALD-Ni/SiO 2 catalyst, containing 6.6 wt% Ni, delivered 81.4% CO 2 conversion and 98.4% CH 4 selectivity at 360 °C and 0.1 MPa. The catalyst also retained stable performance during a 100-hour continuous test, with negligible coke formation and limited Ni sintering. Hence, FB-ALD is a scalable and precise platform for designing active, durable, and low-metal-loading Ni/SiO 2 methanation catalysts.