Mass production of a single-atom cobalt photocatalyst for high-performance visible-light photocatalytic CO2 reduction

The photocatalytic reduction of carbon dioxide (CO2RR) into value-added chemical products is a promising way to enrich energy supply and reduce CO2 emission. The proposal of a high-efficiency, low-cost and easy-to-operate photocatalyst is an essential segment for promoting the CO2RR from small-scale laboratory examination to large-scale industrial application. Herein, we first come up with a Co photocatalyst with isolated Co single atoms anchored on a commercial super conductive carbon black (Co-SA@SP-800) and employ it to effectively boost the photocatalytic CO2 reduction reaction. Large scale production of the Co-SA@SP-800 catalyst can be achieved by a simple and practical adsorption-pyrolysis method. The as-prepared Co-SA@SP-800 catalyst presents remarkable photoactivity and CO selectivity with a CO production yield of 1.64 x 10(4) mu mol g(-1) and a CO selectivity of 84.2% after 2 h of UV illumination in a heterogeneous system, and significantly outperforms other reference samples and most of the other efficient photocatalysts reported recently toward the conversion of CO2. In situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was carried out to investigate the reaction intermediates during the photocatalytic CO2RR. Control experiments and theoretical calculations revealed that the isolated single atomic Co-N-4 sites greatly lower the energy barrier for the desorption of CO* during CO2-to-CO conversion, while suppressing H-2 evolution in the competing water splitting reaction. This work provides valuable new insights for rationally designing and synthesizing high-performance single atom catalysts for photocatalytic CO2 reduction with ease of large-scale production.