Metal-phthalocyanine complexes as electrocatalysts for the multi-electron reduction of carbon dioxide

The electrocatalytic conversion of the greenhouse gas CO2 to reduced products is an area of intensive research at the current time, as this offers a potential route for the production of synthetic fuels and chemical feedstocks from an abundant source. Among the various classes of catalysts explored for CO2 electroreduction, metal-phthalocyanine compounds are amongst the most promising on account of their versatility and ease of functionalization. The majority of studies on these complexes report CO as the dominant product of CO2 electroreduction. However, a number of recent studies have shown that certain metal-phthalocyanine complexes can catalyze multi-electron (n > 2) reductions of carbon dioxide, yielding products of higher value and utility than CO. However, there are remain opportunities for significant improvements in terms of Faradaic efficiencies and product selectivities. In this review, we provide a comprehensive overview of the latest advances in the development of metal-phthalocyanine catalysts for CO2 reduction to products other than CO (with a particular emphasis on literature published since 2019). Our aim is to present a summary of the progress achieved thus far in this rapidly-evolving field and to offer insights and perspectives to guide future research efforts.