Conjugated microporous polymers are a new class of porous materials with an extended π-conjugation in an amorphous organic framework. Owing to the wide-ranging flexibility in the choice and design of components and the available control of pore parameters, these polymers can be tailored for use in various applications, such as gas storage, electronics and catalysis. Here we report a class of cobalt/aluminium-coordinated conjugated microporous polymers that exhibit outstanding CO2 capture and conversion performance at atmospheric pressure and room temperature. These polymers can store CO2 with adsorption capacities comparable to metal-organic frameworks. The cobalt-coordinated conjugated microporous polymers can also simultaneously function as heterogeneous catalysts for the reaction of CO2 and propylene oxide at atmospheric pressure and room temperature, wherein the polymers demonstrate better efficiency than a homogeneous salen-cobalt catalyst. By combining the functions of gas storage and catalysts, this strategy provides a direction for cost-effective CO2 reduction processes.

The voltammetric electrooxidation rates of formic acid, formaldehyde, and methanol in acidic electrolyte on carbon-supported platinum nanoparticle films with varying particle diameters (d) in the range of ca. 2−9 nm are examined with the objective of comparing the nanoparticle size sensitivity for these related yet distinct electrocatalytic processes. The reaction rates on the larger nanoparticles (d > 4 nm) are similar to those observed on polycrystalline Pt when normalized to the same microscopic Pt surface area. As noted previously, the rates of methanol electrooxidation decrease for Pt nanoparticle diameters below 4 nm. However, formic acid electrooxidation exhibits the opposite behavior, with rates increasing markedly for d < 4 nm, while formaldehyde electrooxidation displays little sensitivity to the Pt nanoparticle size. However, the extent of chemisorbed CO formation from all three reactants, as deduced from voltammetric and infrared spectral data, diminishes with decreasing d, the CO coverages for a given nanoparticle size being in the order methanol < formic acid < formaldehyde. These nanoparticle-size-dependent electrocatalytic and CO adsorptive findings are consistent with the occurrence of a Pt site “ensemble effect”, where reactant dehydrogenation to form CO, and also in the case of formaldehyde and especially methanol to yield the reactive intermediate en route to CO2 production, is impeded by the sharply decreasing availability of contiguous Pt terrace sites for d < 4 nm. This structural model is consistent with infrared measurements using CO as a nanoparticle structural probe, which show a rapidly decreasing proportion of terrace relative to edge Pt sites for d < 4 nm, in harmony with atomic packing considerations. The markedly enhanced electrocatalyic rates for formic acid oxidation on the smaller nanoparticles are attributed to the lack of a “Pt site ensemble” requirement for this process, coupled with decreased CO poisoning:  unlike the other two reactions, oxygen addition (from coadsorbed −OH) is not necessarily required in order to produce CO2 from formic acid.