Efficient Photocatalytic Reduction of CO2 to CO Using NiFe2O4@N/C/SnO2 Derived from FeNi Metal-Organic Framework.

Abstract

Use of light is considered an effective approach to convert CO2 into usable chemical energy. In the present study, an iron- and nickel-containing bimetallic metal-organic framework (MOF) was synthesized via a simple solvothermal route. SnO2 was then composited with the said MOF, and the obtained material was calcined and annealed to fabricate a series of nanophotocatalysts. The annealed sample displayed superior photocatalytic activity to the calcined sample, possibly due to the carbon-nitrogen layer formed after annealing mediating the charge-transfer process. The results of photocatalytic experiments indicated that using [Ru(bpy)3]Cl2·6H2O as a photosensitizer and triethanolamine (TEOA) and acetonitrile (MeCN) as sacrificial agents, the catalyst sample was annealed at 450 °C (NiFe2O4@N/C/SnO2-450) to afford the highest CO yield from CO2 (2057.41 μmol g-1 h-1). The increase in the photocatalytic ability of the nanocomposites is basically attributed to multiple synergistic effects between NiFe2O4 and SnO2, which reduce the recombination probability of the photo-induced electrons and holes. Ultimately, a photocatalytic reaction mechanism is proposed for NiFe2O4@N/C/SnO2 in the reduction of CO2.