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Carbon dioxide (CO2) emissions are an important environmental issue that causes greenhouse and climate change effects on the earth. Nowadays, CO2 has various conversion methods to be a potential carbon resource, such as photocatalytic, electrocatalytic, and photo-electrocatalytic. CO2 conversion into value-added products has many advantages, including facile control of the reaction rate by adjusting the applied voltage and minimal environmental pollution. The development of efficient electrocatalysts and improving their viability with appropriate reactor designs is essential for the commercialization of this environmentally friendly method. In addition, microbial electrosynthesis which utilizes an electroactive bio-film electrode as a catalyst can be considered as another option to reduce CO2. This review highlights the methods which can contribute to the increase in efficiency of carbon dioxide reduction (CO2R) processes through electrode structure with the introduction of various electrolytes such as ionic liquid, sulfate, and bicarbonate electrolytes, with the control of pH and with the control of the operating pressure and temperature of the electrolyzer. It also presents the research status, a fundamental understanding of carbon dioxide reduction reaction (CO2RR) mechanisms, the development of electrochemical CO2R technologies, and challenges and opportunities for future research. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting is an eco-friendly method for producing clean and sustainable hydrogen fuels. Compared with the fabrication of solar hydrogen using n-type metal oxide semiconductor photoanodes, that of solar hydrogen using p-type metal oxide semiconductor photocathodes has not been researched as thoroughly. Therefore, this study investigated the effect of drop casting time on the PEC performance of a prepared CuBi2O4 photocathode. XPS, HRTEM, UV-DRS, Raman spectroscopy, XRD, and SEM analyses were used to characterize the prepared CuBi2O4 photocathode. Owing to the high charge separation and transfer, the photocurrent density of the CuBi2O4 photocathode was ~0.6 mA cm−2 at 0.3 V vs. RHE. The nanoporous CuBi2O4 photocathode exhibited a high photocurrent density of up to 1.2 mA cm−2 at 0.3 V vs. RHE with H2O2 as a sacrificial agent. Mott–Schottky and impedance measurements were also performed on the CuBi2O4 photocathode to estimate its acceptor density and charge-transfer resistance. [ABSTRACT FROM AUTHOR]

Epoxy resins are key materials used in various applications, including coatings, adhesives, and composites. Tougheners, such as nanoparticles, soft polymers, elastomeric polyurethanes, and core/shell particles, have been widely applied to compensate for the brittleness of the epoxy matrix and to enhance the impact resistance. Modifying epoxy resin by reacting it with a flexible component is one of the representative methods to overcome the weakness of cured epoxy polymers upon impact. For introducing flexible parts, we synthesized three types of epoxy‐modified resins by reacting acid anhydride with glycidol, followed by reaction with bisphenol [F, S, or J] glycidyl ether to produce flexible modified epoxy resins. Mechanical tests, such as flexural strength and impact resistance tests, were performed by adding various amounts of the synthesized resin to the epoxy composites. The results of these tests suggest that the modified resins were effective in improving the toughness of the epoxy matrix. [ABSTRACT FROM AUTHOR]

The synthesis of bio‐based monomers and polymers from renewable feedstock, such as plant biomass, is desirable because of the depletion of fossil fuel resources and the reliance of thermosetting epoxy resin on non‐renewable petrochemical monomers. Despite the excellent polymeric properties of bisphenol‐based epoxy resins, these negatively impact human health. Herein, the synthesis of self‐curable epoxy polymers from the bio‐based material isoeugenol by forming α‐hydroxyl esters is reported. The epoxides are named AB (single epoxide and ester groups) and A2B2 (double epoxide and ester groups), based on the number of active ester and epoxide groups. The materials derived from the bio‐based material, AB and A2B2, were initiated with and without the catalyst N,N′‐dimethylaminopyridine (DMAP) and curing agent diaminodiphenylmethane. Without the catalyst, AB and A2B2 self‐polymerized at 247 and 210°C, respectively. Notably, the polymerization temperatures for AB and A2B2 decreased after the addition of DMAP. The self‐cured epoxy resin without the catalyst showed the highest thermal stability and glass transition temperature (Tg = 156°C). Degradation and recovery studies suggested forward that 51% of the material could be recovered and 94% of the polymer could be degraded from the self‐cured A2B2 in 25 wt% NaOH solution. [ABSTRACT FROM AUTHOR]

Although the production of cyclic carbonates from CO2 and epoxides can be promoted by eco-friendly halogen- and metal-free organic catalysts, its homogeneity complicates the catalyst reuse. Herein, we synthesized solid multifunctional alkanolamines using simple epoxy and amine reactions, and analyzed their structures by IR and 13C-NMR. Then, we employed these as catalysts for CO2 cycloaddition with propylene oxide, obtaining propylene carbonate in 98% yield after 3 h at 120 °C. Moreover, at 60 °C, the reaction was successfully repeated five times and a product yield of 50% was maintained throughout. [ABSTRACT FROM AUTHOR]

The slow anodic oxygen evolution reaction (OER) significantly limits electrocatalytic water splitting for hydrogen production. We proposed the electrocatalyst for glucose oxidation by Ta-doping NiFe LDH nanosheets to simultaneously obtain glucaric acid (GRA) and hydrogen gas as a useful byproduct. Superior glucose oxidation reaction (GOR) activity is demonstrated by the optimized Ta-NiFe LDH, which has a low overpotential of 192 mV, allowing for a small Tafel slope of 70 mV dec -1 and a current density of 50 mA cm -2 . The Ta NiFe LDH-oxidized glucose to GRA with a 72.94% yield and 64.3% Faradaic efficiency at 1.45 V RHE . Herein, we report the Ta NiFe LDH/NF electrode for the GOR&hydrogen evolution reaction (HER), which exhibits a cell voltage of 1.62 V to reach a current density of 10 mA cm -2 , which is 250 mV lower compared to OER&HER (1.87 V). This study reveals that GOR is an energy-efficient and cost-effective method for producing H 2 and valorizing biomass.

This study developed a safe and sustainable route for the epoxidation of cyclohexene using water as the source of oxygen at room temperature and ambient pressure. Here, we optimized the cyclohexene concentration, volume of solvent/water (CH 3 CN, H 2 O), time, and potential on the photoelectrochemical (PEC) cyclohexene oxidation reaction of the α-Fe 2 O 3 photoanode. The α-Fe 2 O 3 photoanode epoxidized cyclohexene to cyclohexene oxide with a 72.4 ± 3.6% yield and a 35.2 ± 1.6% Faradaic efficiency of 0.37 V vs Fc/Fc + (0.8 V Ag/AgCl ) under 100 mW cm -2 . Furthermore, the irradiation of light (PEC) decreased the applied voltage of the electrochemical cell oxidation process by 0.47 V. This work supplies an energy-saving and environment-benign approach for producing value-added chemicals coupled with solar fuel generation. Epoxidation with green solvents via PEC methods has a high potential for different oxidation reactions of value-added and fine chemicals.