Photothermal conversion of CO2 with high activity and stability over Ni-based composite nanochains

Abstract

Solar-driven CO2 conversion to valuable products is a promising way to realize a carbon-neutral economy. Great progress has been made on photothermal catalysts with high selectivity and activity, but improved materials via a more efficient and cost-effective synthetic strategy are needed. Herein, we present a one-pot synthetic strategy of nickel/metal oxide nanostructured chains for the photothermal conversion of CO2 into methane. Nickel ions were in-situ reduced in a growth solution in the presence of alumina nanocrystals, where the formation and assembly of magnetic nickel nanoparticles decorated with Al2O3 nanocrystals simultaneously proceeded. The obtained composite nanochains exhibited a stable production rate of CH4 as high as 128 mmol·gcat−1·h−1 with ∼ 99% selectivity in continuous cycling test. The structure analysis of the Ni/Al2O3 composite indicates that a small amount of Al2O3 nanocrystals introduced in the nanocomposites not only ensures sufficient active site exposure to reactive molecules but also prevents the nickel nanoparticles from drastically sintering at high temperatures. The flexibility of this rapid synthesis strategy is also verified by using titania for the synthesis of Ni/TiO2 nanocatalysts, and stable catalytic performance has been achieved, suggesting its potential for practical solar-driven CO2 hydrogenation to valuable fuels.