Critical Aspects of Metal–Organic Framework‐Based Materials for Solar‐Driven CO₂ Reduction into Valuable Fuels

Abstract

Photoreduction of CO2 into value‐added fuels is one of the most promising strategies for tackling the energy crisis and mitigating the “greenhouse effect.” Recently, metal–organic frameworks (MOFs) have been widely investigated in the field of CO2 photoreduction owing to their high CO2 uptake and adjustable functional groups. The fundamental factors and state‐of‐the‐art advancements in MOFs for photocatalytic CO2 reduction are summarized from the critical perspectives of light absorption, carrier dynamics, adsorption/activation, and reaction on the surface of photocatalysts, which are the three main critical aspects for CO2 photoreduction and determine the overall photocatalytic efficiency. In view of the merits of porous materials, recent progress of three other types of porous materials are also briefly summarized, namely zeolite‐based, covalent–organic frameworks based (COFs‐based), and porous semiconductor or organic polymer based photocatalysts. The remarkable performance of these porous materials for solar‐driven CO2 reduction systems is highlighted. Finally, challenges and opportunities of porous materials for photocatalytic CO2 reduction are presented, aiming to provide a new viewpoint for improving the overall photocatalytic CO2 reduction efficiency with porous materials.

Origin of the Photocatalytic Activity of Crystalline Phase Structures

“…From the results of Figure f, it could be concluded that there were no significant defects in ZIS-c/h, so the influence of surface defects was also excluded. As we all know,the photocatalytic reaction generally considers three important steps: light quantum absorption efficiency, carrier separation and migration, and surface reaction . From the diffuse reflectance spectrum (DRS) spectrum of Figure g, it can be obtained that the band gaps of ZIS-c and ZIS-h are 2.09 and 2.37 eV, respectively, so the light quantum absorption efficiency was not the main reason for the activity difference between ZIS-c and ZIS-h. Then, we further combined the XPS-VB spectrum to obtain the energy level potentials of ZIS-c and ZIS-h (Figure h,i).…”

Utilization of Low-Concentration CO2 with Molecular Catalysts Assisted by CO2-Capturing Ability of Catalysts, Additives, or Reaction Media

“…MOFs have been actively investigated as a new class of adsorbers for gas storage and separation due to their porous structure and high surface areas. − , A remarkable feature of MOFs is their highly flexible structures and characteristics. Typical MOFs are constructed with nodes and linkers (Figure ).…”

“…The CO 2 -capturing abilities of solutions containing such additives or ILs lead to high local concentrations around catalysts. The CO 2 adsorption ability of metal–organic frameworks (MOFs) also increases the local CO 2 concentration around catalysts. − Some MOFs show high adsorption amounts and selectivity for CO 2 ; therefore, loading CO 2 -Red catalysts into the skeletons of MOFs will promote the reaction between catalysts and CO 2 even under LC-CO 2 . The catalytic systems constructed with CO 2 -capturing media will be described in Section .…”

MXene-Based Photocatalysts and Electrocatalysts for CO2 Conversion to Chemicals

“…The charge carrier recombination in Step (2) should ideally be suppressed; otherwise, this redox process will not occur. Several governing factors affect the efficiency of PCR, such as the quantity of uptake CO 2 , the concentration of the absorbed CO 2 on the surface of photocatalyst materials, and the activated catalytic sites [39].…”