前文介绍了将CO2转化为碳纳米管的新技术——清理CO2排放可创造价值数十万亿美金的利润。本文再介绍来自《自然》（Nature）杂志网站的另一则新成果。法国（Université Paris Diderot）和阿根廷（Universidad Nacional de Córdoba, Argentina）的研究人员合作，利用铁配合物（作为催化剂）和太阳光可以将CO2转化为甲烷。详见Heng Rao, Luciana C. Schmidt, Julien Bonin, Marc Robert. Visible-light-driven methane formation from CO2 with a molecular iron catalyst. Nature, 2017, DOI: 10.1038/nature23016.图1就是来自《自然》杂志发表的论文中利用铁化合物（作为催化剂）和太阳光可以将CO2转化为甲烷机理图示。
Fig. 1 Sketch of the proposed mechanism for CO2 reduction to CH4 by catalyst 1. Credit: Nature (2017). DOI: 10.1038/nature23016
来自法国巴黎狄德罗大学（Université Paris Diderot）和来自阿根廷的科尔多瓦国立大学（Universidad Nacional de Córdoba）研究人员合作，已经发现了一种可以用来将CO2转换成甲烷的化学反应过程。他们的论文于2017年7月17日已在《自然》杂志网站上发表,该研究小组描述了他们的技术是怎样工作的以及他们对其进行改进的一些想法。
Converting carbon dioxide to methane using iron and sunlight
New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
Abstract
Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.
