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Abstract Climate change and global warming problem are becoming the serious issue and some action is necessary in order to mitigate the rising temperature. CO2 increase is one of the reason for temperature rise, and the technology to convert CO2 to beneficial energy or chemical substance could be one of the key solution (CO2 photocatalytic reduction). Metal–organic frameworks (MOFs) have gained much attention owing to their extremely large surface areas, tunable fine structures, and potential applications in many areas. Recently, MOFs have been demonstrated to be promising materials for CO2 photocatalytic reduction. This review summarized recent research progresses in photocatalytic reduction using MOFs. MOFs were classified mainly by the type of metal center, and the feature and tendency against their functions towards CO2 photocatalytic activity will be explained.

Enzymes reign over inorganic and organometallic catalysts in aspects of conversion and product selectivity. Natural products are always produced in small quantities and to mimic such biological setups for large-scale production requires harsh solvent systems and elevated temperatures to promote the reaction rates, conditions known to denature most enzymes. Immobilization of enzymes has been used to surpass such challenges in addition to allowing single and multiple enzyme reactions in contrasting reaction media. This review addresses the different techniques used to support and stabilize biocatalysts. Silica is the oldest support material used to encapsulate/immobilize enzymes and like all immobilization techniques, it significantly increases the thermal stability, extreme pH tolerance, recyclability and lifespan of biocatalysts. Immobilization supports with reactive functional groups such as metal salts, metal-, covalent- and hydrogen-bonded organic frameworks work well with enzymes that exhibit hydrophobic tolerance. Bienzymatic immobilization by one support system or the use of multiple supports for a single enzyme and further enhancement of immobilized enzymes to increase activity is possible. Some immobilization support systems such as silica and enzyme hybrid nanoflowers work well with both hydrophilic/hydrophobic and metal-free/metal-containing enzymes. Solid supports such as natural fibers and metal salts, for example, polyoxometalate hybrids stretch the enzyme’s thermal stability further (>60 °C) and also accommodate more enzyme particles.

This study investigates the utilisation of organometallic network frameworks composed of fourth-period transition metals and tetrahydroxyquinone (THQ) in electrocatalytic CO2 reduction. Density functional theory (DFT) calculations were employed in analysing binding energies, as well as the stabilities of metal atoms within the THQ frameworks, for transition metal TM-THQs ranging from Y to Cd. The findings demonstrate how metal atoms could be effectively dispersed and held within the THQ frameworks due to sufficiently high binding energies. Most TM-THQ frameworks exhibited favourable selectivity towards CO2 reduction, except for Tc and Ru, which experienced competition from hydrogen evolution reaction (HER) and required solution environments with pH values greater than 5.716 and 8.819, respectively, to exhibit CO2RR selectivity. Notably, the primary product of Y, Ag, and Cd was HCOOH; Mo produced HCHO; Pd yielded CO; and Zr, Nb, Tc, Ru, and Rh predominantly generated CH4. Among the studied frameworks, Zr-THQ displayed values of 1.212 V and 1.043 V, corresponding to the highest limiting potential and overpotential, respectively, while other metal–organic frameworks displayed relatively low ranges of overpotentials from 0.179 V to 0.949 V. Consequently, it is predicted that the TM-THQ framework constructed using a fourth-period transition metal and tetrahydroxyquinone exhibits robust electrocatalytic reduction of CO2 catalytic activity.

For the excellent drug delivery systems, advanced functional materials are indispensable. In recent years, mesoporous materials have shown a promising prospect and attracted much attention in the field of drug delivery. The research of mesoporous materials as drug carriers becomes to be a hot-spots. As a drug vehicle, it is favored by scientists due to the advantages in increasing drug dissolution and bioavailability, improving drug stability, sustained and controlled drug release, reducing drug side effects, good biocompatibility, targeting and so on. The anticipated in vivo performance for the mesoporous materials based drug delivery systems can be improved through optimizing the synthesis conditions or modifying the materials. In the paper, mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), organic frameworks (OFs), mesoporous hydroxyapatite (mHAp) are selected as the representative mesoporous materials. The structural characteristics, preparation methods, application in the field of drug delivery of above materials are reviewed, and the future research is prospected.