Efficient Solar-Driven CO 2 Methanation and Hydrogen Storage Over Nickel Catalyst Derived from Metal-Organic Frameworks with Rich Oxygen Vacancies.

Solar-driven photothermal conversion of carbon dioxide (CO 2 ) to methane (CH 4 ) is a promising approach to remedy energy shortage and climate changes, where highly efficient photothermal catalysts for CO 2 methanation urgently need to be designed. Herein, nickel-based catalysts (Ni/ZrO 2 ) derived from metal-organic frameworks (MOFs) are fabricated and studied for photothermal CO 2 methanation. The optimized catalyst 50Ni/ZrO 2 achieves a stable CH 4 production rate of 583.3 mmol g -1  h -1 in a continuous stability test, which is almost tenfold higher than that of 50Ni/C-ZrO 2 synthesized via commercial ZrO 2 . Physicochemical properties indicate that 50Ni/ZrO 2 generates more tetragonal ZrO 2 and possesses more oxygen vacancies (OVs) as well as enhanced nickel-ZrO 2 interaction. As a result, 50Ni/ZrO 2 exhibits the strong abilities of light absorption and light-to-heat conversion, superior adsorption capacities of reactants (H 2 , CO 2 ), and an intermediate product (CO), which finally boosts CH 4 formation. This work provides an efficient strategy to design a photothermocatalyst of CO 2 methanation through utilizing MOFs-derived support.