Highly efficient photocatalytic reduction of CO2 and H2O to CO and H2 with a cobalt bipyridyl complex

The development of efficient molecular catalysts for visible-light driven CO2 reduction, based on abundant materials, is necessary to meet energy demands and address environment problems. In this work, a Co(bpy)(2)Cl-2 catalyst was developed and showed high efficiency and durability for the photocatalytic reduction of CO2 and protons. Yields of CO and H-2 as high as 62.3 and 69.9 mu mol were achieved and the turnover numbers (TONs) reached 6230 and 6990, respectively, under light irradiation (lambda > 420 nm) for 4 h, indicating that the mixture gases could be a candidate as syngas. The apparent quantum yield was determined to be 2.1% for CO. Mechanistic studies revealed oxidative quenching of the photosensitizer Ru(bpy)(3)Cl-2 by the catalyst. The photocatalytic performance, flexible synthesis and non-noble metal catalyst in our system show great promise for the practical application of Co(bpy)(2)Cl-2 to photocatalytic reduction of CO2. (c) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.