https://doi.org/10.1016/j.mtsust.2022.100149
“Carbon dioxide (CO2) is known as one of the major greenhouse gases contributing to the global climate change issue. In recent decades, many strategies have been attempted in various technologies (carbon capture and storage [1] and carbon capture and utilization [3]) to reduce global CO2. Although some progress has been made, the current state-of-the-art carbon capture technologies are still expensive and energy intensive [59]. Due to the effective packing and close way of CO2 on the pore surface of absorbents, the high porosity and surface areas of MOFs offer an opportunity for a large CO2 adsorption capacity [60]. Meanwhile, the interaction between CO2 and exposed metal sites of MOFs can also benefit CO2 capture. Reducing regeneration costs is also a beneficial point for the application MOFs in carbon capture. Traditional gas liberation technologies are vacuum swing adsorption (VSA), temperature swing adsorption (TSA), pressure swing adsorption (PSA), and their combinations [61]. However, a large amount of energy is required in VSA and PSA to control pressure for driving adsorbed gases to be released from networks of MOFs. Although waste heat can be utilized in TSA [62] MOFs, such thermally insulating is challenging to be applied on a large scale. In general, traditional technologies for the release of adsorbed CO2 have high energy requirements. Therefore, new triggers that use renewable energy are strongly desired. Ultimately, MOFs with maximum gas capturing capacity can further reduce the costs and energy for CO2 capture applications [59].
The most attractive feature of photoswitching MOFs is the use of light (or sunlight) as a renewable energy source for triggering CO2 release from MOFs. Light is a highly appealing stimulus for driving CO2 liberation. If the absorbents combined strongly light absorption with the dramatic desorption of large quantities of CO2, drastically energy saving could be realized [31]. Therefore, photoswitching MOFs received much attention because the most attractive feature of this material is the use of light (or sunlight) as a renewable energy source for triggering CO2 release from MOFs (see Table 1).”