A critical review in recent developments of metal-organic-frameworks (MOFs) with band engineering alteration for photocatalytic CO2 reduction to solar fuels

Coordination Polymers with 2,2':6',2″-Terpyridine Earth-Abundant Metal Complex Units for Selective CO2 Photoreduction

Combining molecular metal complexes into coordination polymers (CPs) is an effective strategy for developing photocatalysts for CO₂ reduction; however, most such reported catalysts are noble metal-containing CPs. Herein, two novel Zr-containing bimetallic CPs, Co-Zr and Ni-Zr, were designed and successfully synthesized by connecting 2,2':6',2″-terpyridine-based molecular earth-abundant metal (Co or Ni) complexes with ZrO₈ nodes. Both CPs were applied as catalysts for CO₂ photoreduction to selectively produce CO. The catalytic performance of Co-Zr is better than that of Ni-Zr with a yield of 3654 μmol (g of catalyst)^-1 for CO in 6 h (TON = 18.2). The difference between these two catalysts was analyzed with respect to band structure and charge migration ability. This work provides an effective way to introduce molecular earth-abundant metal complexes into coordination polymers for the construction of efficient noble metal-free CO₂ photocatalysts.

Interface modification by defect engineering for g-C3N4/LaPO4−x nanorods towards efficient CO2 photoreduction

In this work, a series of specific surface defects are introduced at the interface of LaPO4/g-C3N4 composites.

Semiconductor photocatalysts and mechanisms of carbon dioxide reduction and nitrogen fixation under UV and visible light

The review summarizes the current knowledge about heterogeneous semiconductor photocatalysts that are active towards photocatalytic reduction of carbon dioxide and molecular nitrogen under visible and near-UV light. The main classes of these photocatalysts and characteristic features of their application in the target processes are considered. Primary attention is given to photocatalysts based on titanium dioxide, which have high activity and stability in the carbon dioxide reduction. For the first time, the photofixation of nitrogen under irradiation in the presence of various semiconductor materials is considered in detail.

The bibliography includes 264 references.

Effect of Micropores of a Porous Coordination Polymer on the Product Selectivity in RuII Complex-catalyzed CO2 Reduction

To develop an efficient CO2 reduction catalyst, hybridizing a molecular catalyst and a porous coordination polymer (PCP) is a promising strategy because it can combine both advantages of the precise reactivity control of the former and the CO2 adsorption property of the latter. Although several PCP hybrid catalysts have been reported to date, the CO2 sorption behavior and the CO2 reduction reactivity have been investigated separately, and the CO2 enrichment during the catalysis is still unclear. We report CO2 photoreduction under different temperatures and pressures using a PCP-RuII complex hybrid catalyst. The product selectivity (CO or HCOOH) varied depending on the reaction conditions. The altered selectivity could be interpreted in terms of the CO2 capture in the micropores of a PCP.

Electrochemical Incorporation of Carbon Dioxide into Fluorotoluene Derivatives under Mild Conditions

One of the main challenges to combat climate change is to eliminate or reuse Carbon dioxide (CO2), the largest contributor to the greenhouse gases that cause global warming. It is also important to synthesize compounds through greener technologies in order to obtain more environmentally friendly solutions. This study describes the electrocarboxylation process of α,α,α-trifluorotoluene using different working electrodes (glassy carbon, silver and copper) and electrolytes (polar aprotic solvent and ionic liquid). Carboxylated compounds were obtained in the same way in both electrolytic medias with more than 80% conversion rates, high yields, good selectivity, and moderate efficiencies using silver and copper as cathodes in organic electrolytes and ionic liquids.

An investigation of affecting factors on MOF characteristics for biomedical applications: A systematic review

Metal-organic frameworks (MOFs) are a fascinating class of crystalline porous materials composed of metal ions and organic ligands. Due to their attractive properties, MOFs can potentially offer biomedical field applications, such as drug delivery and imaging. This study aimed to systematically identify the affecting factors on the MOF characteristics and their effects on structural and biological characteristics. An electronic search was performed in four databases containing PubMed, Scopus, Web of Science, and Embase, using the relevant keywords. After analyzing the studies, 20 eligible studies were included in this review. As a result, various factors such as additives and organic ligand can influence the size and structure of MOFs. Additives are materials that can compete with ligand and may affect the nucleation and growth processes and, consequently, particle size. The nature and structure of ligand are influential in determining the size and structure of MOF. Moreover, synthesis parameters like the reaction time and initial reagents ratio are critical factors that should be optimized to regulate the size and structure. Of note is that the nature of the ligand and using a suitable additive can control the porosity of MOF. The more extended ligands aid in forming large pores. The choice of metallic nodes and organic ligand, and the MOF concentration are important factors since they can determine toxicity and biocompatibility of the final structure. The physicochemical properties of MOFs, such as hydrophobicity, affect the toxicity of nanoparticles. An increase in hydrophobicity causes increased toxicity of MOF. The biodegradability of MOF, as another property, depends on the organic ligand and metal ion and environmental conditions like pH. Photocleavable ligands can be served for controlled degradation of MOFs. Generally, by optimizing these affecting factors, MOFs with desirable properties will be obtained for biomedical applications.