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Abstract We synthesized the silver‐decorated copper microsphere via the hydrothermal method followed by photoreduction of silver ions. Sub 100 nm Ag nanoparticles anchored on the surface of Cu microspheres enhance the electrochemical performance and the selectivity of the CO₂reduction into CH₄. Incorporating Ag nanoparticles onto Cu lowers the charge transfer resistance, enhancing the catalyst's conductivity and active site and increasing the rate of CO₂reduction. The faradaic efficiency of silver nanoparticles decorated copper microsphere for methane was 70.94 %, almost twice that of a copper microsphere (44 %). The electrochemical performance showed higher catalytic properties, stability, and faradaic efficiency of silver‐decorated copper microspheres. 

Abstract Cu₂O has been successfully synthesized in different morphologies/sizes (nanoparticles and octahedrons) via a low-temperature chemical reduction method. Trapping metal ions in an ice cube and letting them slowly melt in a reducing agent solution is the simplest way to control the nanostructure. Enhancement of charge transfer and transportation of ions by Cu₂O nanoparticles was shown by cyclic voltammetry and electrochemical impedance spectroscopy measurements. In addition, nanoparticles exhibited higher current densities, the lowest onset potential, and the Tafel slope than others. The Cu₂O electrocatalyst (nanoparticles) demonstrated the Faraday efficiencies (FEs) of CO, CH₄, and C₂H₆up to 11.90, 76.61, and 1.87%, respectively, at −0.30 V versus reference hydrogen electrode, which was relatively higher FEs than other morphologies/sizes. It is mainly attributed to nano-sized, more active sites and oxygen vacancy. In addition, it demonstrated stability over 11 h without any decay of current density. The mechanism related to morphology tuning and electrochemical CO₂reduction reaction was explained. This work provides a possible way to fabricate the different morphologies/sizes of Cu₂O at low-temperature chemical reduction methods for obtaining the CO, CH_4,and C₂H₆products from CO₂ 

Cerium oxide (CeO₂) photo/electrocatalysts for energy storage and environmental applications have attracted considerable interest because of stable crystal structure, low toxicity/cost, superior chemical stability, stable redox (Ce³⁺/Ce⁴⁺) pairs, abundant oxygen defects, and capablility for intense interaction with other materials. However, the wide bandgap and poor conductivity lower the CeO₂photo/electrocatalytic and energy storage performances. To overcome these limitations, various modification strategies (tuning morphology, doping or loading of metal nanoparticles, and heterostructures) have been applied for the improvement of photocatalytic (removal of organic contaminants from water/wastewater and H₂production and CO₂reduction reactions) efficiency, electrocatalytic (hydrogen/oxygen evolution reactions and CO₂reduction reactions), and energy storage performances (supercapacitor) of CeO₂‐based materials. Herein, the recent progress of CeO₂‐based materials for electro(photo)catalysis and energy storage applications has been discussed. The challenges and possible direction of CeO₂‐based materials for electro(photo)catalysis and energy storage applications have been emphasized. Furthermore, this comprehensive review is expected to advance the design of CeO₂‐based materials and their applications in electro(photo)catalysis and energy. 

Hydrothermal and photoreduction/deposition methods were used to fabricate Ag nanoparticles (NPs) decorated CoMoO₄rods. Improvement of charge transfer and transportation of ions by making heterostructure was proved by cyclic voltammetry and electrochemical impedance spectroscopy measurements. Linear sweep voltammetry results revealed a fivefold enhancement of current density by fabricating heterostructure. The lowest Tafel slope (112 mV/dec) for heterostructure compared with CoMoO₄(273 mV/dec) suggested the improvement of electrocatalytic performance. The electrochemical CO₂reduction reaction was performed on an H-type cell. The CoMoO₄electrocatalyst possessed the Faraday efficiencies (FEs) of CO and CH₄up to 56.80% and 19.80%, respectively at  − 1.3 V versus RHE. In addition, Ag NPs decorated CoMoO₄electrocatalyst showed FEs for CO, CH₄, and C₂H₆were 35.30%, 11.40%, and 44.20%, respectively, at the same potential. It is found that CO₂reduction products shifted from CO/CH₄to C₂H₆when the Ag NPs deposited on the CoMoO₄electrocatalyst. In addition, it demonstrated excellent electrocatalytic stability after a prolonged 25 h amperometric test at  − 1.3 V versus RHE. It can be attributed to a synergistic effect between the Ag NPs and CoMoO₄rods. This study highlights the cooperation between Ag NPs on CoMoO₄components and provides new insight into the design of heterostructure as an efficient, stable catalyst towards electrocatalytic reduction of CO₂to CO, CH₄, and C₂H₆products. 

Metal indium sulfides (ZnIn₂S₄, NiIn₂S₄, and CuInS₂) were synthesized using a hydrothermal method for electrochemical reduction of CO₂in to methane. 

A laboratory-synthesized triblock copolymer poly(ethylene oxide-b-acrylic acid-b-styrene) (PEG-PAA-PS) was used as a template to synthesize hollow BaCO3 nanoparticles (BC-NPs). The triblock copolymer was synthesized using reversible addition–fragmentation chain transfer radical polymerization. The triblock copolymer has a molecular weight of 1.88 × 104 g/mol. Transmission electron microscopy measurements confirm the formation of spherical micelles with a PEG corona, PAA shell, and PS core in an aqueous solution. Furthermore, the dynamic light scattering experiment revealed the electrostatic interaction of Ba2+ ions with an anionic poly(acrylic acid) block of the micelles. The controlled precipitation of BaCO3 around spherical polymeric micelles followed by calcination allows for the synthesis of hollow BC-NPs with cavity diameters of 15 nm and a shell thickness of 5 nm. The encapsulation and release of methotrexate from hollow BC-NPs at pH 7.4 was studied. The cell viability experiments indicate the possibility of BC-NPs maintaining biocompatibility for a prolonged time. 

Iron oxide nanoparticles (IONPs) were synthesized via a block copolymer-assisted hydrothermal method and the phase purity and the crystal structure were investigated by X-ray diffraction. The Rietveld analysis of X-ray diffractometer spectra shows the hexagonal phase symmetry of α-Fe2O3. Further, the vibrational study suggests Raman active modes: 2A1g + 5Eg associated with α-Fe2O3, which corroborates the Rietveld analysis and orbital analysis of 2PFe. The superparamagnetic behavior is confirmed by magnetic measurements performed by the physical properties measurement system. The systematic study of the Congo red (CR) interaction with IONPs using a UV-visible spectrophotometer and a liquid chromatography–tandem mass spectrometry system equipped with a triple quadrupole mass analyzer and an electrospray ionization interface shows effective adsorption. In visible light, the Fe2O3 nanoparticles get easily excited and generate electrons and holes. The photogenerated electrons reduce the Fe3+ ions to Fe2+ ions. The Fe2+/H2O2 oxidizes CR by the Fenton mechanism. The strong adsorption ability of prepared nanoparticles towards dyes attributes the potential candidates for wastewater treatment and other catalytic applications. 

Hydrophobic surfaces provide special characteristics for biomedical applications ranging from tunable protein adsorption, cellular interactions, and hemocompatibility to antibacterial coatings. In this research, we biomimic the hair-like micro-whisker structures of magnolia leaf using a synthetic polymeric formulation. Optical and scanning electron microscopy images revealed the presence of micro-whiskers resulting in higher water contact angles. The top layer of the magnolia leaf had a contact angle of 50º as compared to the hydrophobic bottom layer at 98º. A synthetic polymeric formulation was coated on different materials to study its effect on hydrophobicity. The coating was replicated (n=3) on each of the materials used such as glass, polymer, fabric, wood, and stainless steel. A surface tensiometer was used to measure the transition from hydrophilic to hydrophobic interactions between water and the substrate materials. Contact angle measurements revealed an increase in hydrophobicity for all the materials from their original uncoated surface. Glass displayed the highest increase in contact angle from 37º to 90º. Phase analysis of the coated region was performed to characterize the surface exposure of glass substrate to the synthetic polymeric formulation. An increase in the coated region showed a significant increase in contact angle from 50º to 95º. This research lays the foundation to develop and understand hydrophobic coatings for several biomedical applications including non-fouling implant surfaces, lab-on-chip devices, and other diagnostic tools.