Successful CO2 reduction under visible light photocatalysis using porous NiO nanoparticles, an atypical metal oxide

Abstract

An efficient, one-pot wet chemical synthesis strategy for the preparation of NiO nanoparticles has been reported. The nanostructured NiO has surface bound hexamine and it has emerged as a proficient catalyst for the conversion of carbon dioxide (CO₂) into formaldehyde with a maximum turnover number of 369 in the presence of blue LED light. The nano-photocatalyst has shown great catalytic efficiency (in terms of the turnover number) and excellent reusability for the photoreduction of CO₂. To the best of our knowledge this will be the first report on photoreduction of CO₂ to formaldehyde in water under visible light irradiation using NiO nanoparticles as the photocatalyst. The as-prepared NiO nanomaterial has been thoroughly characterized using several spectroscopic and microscopic techniques, e.g. UV-vis spectroscopy, PXRD, XPS, SEM, FESEM and TEM. The mechanism of formation has been predicted from a detailed FTIR analysis.