A Universal Porous Adsorbent for the Selective Capture of Carbon Dioxide

Abstract

<div>Efficient and sustainable methods for carbon dioxide (CO2) capture are essential. Its atmospheric</div><div>concentration must be reduced to meet climate change targets, and its remediation from chemical</div><div>feedstocks and natural gas is vital. While mature technologies involving chemical reactions that trap the</div><div>CO2 do exist, they have many drawbacks. Porous materials with void spaces that are complementary in</div><div>size and electrostatic potential to CO2 offer an alternative. In these materials, the molecular CO2 guests</div><div>are trapped by noncovalent interactions, hence they can be recycled by releasing the CO2 with a low</div><div>energy penalty. Porous materials that are selective towards CO2 when it is present with an array of</div><div>competing gases are challenging to produce. Here, we show how a metal-organic framework, termed</div><div>MUF-16 (MUF = Massey University Framework), is a ‘universal’ adsorbent for CO2 that sequesters</div><div>CO2 from a broad palette of gas streams with record selectivities over competing gases. The position of</div><div>the CO2 molecules captured in the framework pores was determined crystallographically to illustrate</div><div>how complementary noncovalent interactions envelop the guest molecules. The pore environment has a</div><div>low affinity for all other gases, which underpins the benchmark selectivity of MUF-16 for CO2 over</div><div>methane, hydrogen and acetylene. Breakthrough gas separations under dynamic conditions benefit from</div><div>short time lags in the elution of the weakly-adsorbed component to deliver a repertoire of high-purity</div><div>products. MUF-16 is an inexpensive, robust, easily regernarable and recyclable adsorbent that is</div><div>universally applicable to the removal of CO2 from sources such as natural gas, syngas and chemical</div><div>feedstocks.</div>