Abstract: The development of efficient and sustainable methods for decarboxylative transformations is of great importance due to the ease of availability and nontoxicity of carboxylic acids. Despite tremendous efforts in this area, it remains challenging to develop enantioselective transformations direct from carboxylic acids. Herein we disclose a photoelectrocatalytic method for the direct and enantioselective decarboxylative cyanation. The photoelectrochemical reactions convert carboxylic acids to enantioenriched nitriles by employing cerium/copper relay catalysis with a cerium salt for catalytic decarboxylation and a chiral copper complex for stereoselective C-CN formation.

Abstract: The construction of low-cost, highly efficient, and stable electrocatalysts is a significant challenge for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a facile strategy to fabricate ultrathin metal-organic framework (MOF) nanosheet arrays doped with two rare-earth elements, Y and Ce, and self-supported on nickel foam (NF) to enhance the HER and OER performance by constructing abundant active sites and bimetallic synergistic effects. The NiYCe-MOF/NF features an ultrathin nanosheet array structure and is uniformly and richly codoped by Y and Ce. When it was explored as both the anode and cathode electrocatalysts for overall water splitting, it achieved 10 mA cm-2 at 136 and 245 mV for the HER and OER in an alkaline electrolyte, respectively. Notably, an extremely low cell voltage of 1.54 V was required to achieve 100 mA cm-2 in 1.0 M KOH solution, making it a promising substitute for noble-metal catalysts.

Abstract: The great demand for renewable energy has greatly contributed to the development of the solar cell industry. Recently, silicon solar cells have dominated the world market. The ease of processing gives perovskite solar cells (PSCs) an advantage over conventional silicon solar cells. Regular silicon photovoltaics require expensive, multi-step processes accomplished in a specialized ultraclean-chamber facility at an elevated temperature (>1000 °C) and highly vacuumed workspace. Hence, researchers and the solar cell industry have focused on PSC as a great rival to silicon solar cells. Despite this, the highest efficiency was obtained from lead-based PSC, which has a considerably high toxicity issue and low stability related to lead content, so the research field pays attention to lead-free perovskite solar cells. In this digital simulation, tin-based perovskite in this paper, methylammonium tin iodide (MASnI3) with the use of cerium oxide (CeOx) as an electron transporting layer (ETL) with varying percentages of oxygen, which means different shallow donor densities (ND). The optimum value for the thickness of the absorber layer (perovskite) was made, and the current–voltage characteristics and efficiency calculations were also accomplished for the best cell. Then an improvement was made by changing the ND value of CeOx, and the best-optimized cell parameters were: open circuit voltage (VOC) of 0.92 V, short circuit current density (JSC) of 30.79 mA cm−2, power conversion efficiency (PCE) of 17.77%, and fill factor (FF) of 62.86%.

Abstract: The poisoning of sulfur oxides and alkali metals emitted from diesel exhaust to active sites of copper ion-exchanged chabazite (Cu-CHA) catalysts is still present and remains a formidable challenge in practical application. Herein, a bifunctional core–shell structural Cu-SSZ-13@Ce0.75Zr0.25O2 (Cu-SSZ-13@CZO) catalyst was designed and fabricated via a hydrothermally induced self-assembly protocol, and the catalytic activity of Cu-SSZ-13@CZO for selective catalytic reduction (SCR) of nitrogen oxides (NOx) with ammonia was systematically investigated. It unveils that Cu-SSZ-13@CZO features Cu-SSZ-13 as the core and dispersed CZO as the shell and that the CZO shell could not only serve as a sacrificial site protecting the Cu-SSZ-13 active core from SO2 poisoning by the formation of Ce2(SO4)3, which could further act as adsorption sites capturing the K+ through the strong interaction between K+ and cerium sulfate, but also render additional Brønsted acid sites functioning as sacrificial sites to trap K+, thereafter inhibiting the adsorption of K+ directly on active Cu species in the Cu-SSZ-13 core. As a result, the as-constructed Cu-SSZ-13@CZO catalyst, therefore, exhibits perceptibly enhanced coresistance to sulfur and potassium ion poisoning with almost 100% NOx conversion in the temperature window of 275–475 °C as compared to 350–450 °C on pristine Cu-SSZ-13. The finding here may contribute to the fundamental understanding of the coresistance to sulfur oxides and alkali metal poison and thereafter inspire the advancement of a highly efficient NH3-SCR catalyst in the future.

Abstract: In this study, we report the synergistic effect of a metal ion/cluster (cerium nitrate hexahydrate) with an organic linker (2 methyl imidazole) as a nano-hybrid corrosion inhibitor for X65 steel in CO 2 solution. To achieve this fit, a wide empirical study from wet chemical synthesis of Ce-MOF (cerium-metal organic framework), electrochemical method and surface analysis were considered. The empirical data obtained from the electrochemical studies were statistically analyzed via a machine learning model (adaptive neuro fuzzy inference system-ANFIS) considering multi input and single output function (MISO). The outcome revealed that Ce-MOF hindered the dissolution of ferrite and cementite phase of the steel in CO 2 solution. The electrochemical impedance spectroscopy (EIS) revealed a significant rise in resistance to charge transfer with an increase in concentration of Ce-MOF. Polarization data indicated that Ce-MOF exhibited mixed-type inhibitor characteristics. The range of inhibition efficiencies were in the range of 97 and 95% at 0.15 wt. % Ce-MOF for polarization and impedance studies, respectively. The theoretical study shows a flat adsorption orientation of Ce-MOF on the steel surface. Furthermore, the predictive capability of ANFIS model based on statistical norms; shows that the coefficient of determination (R 2 ) is unity. From the statistical view point, much credibility was attributed to ANFIS model with robust description of the nonlinear interactions between the independent and dependent variables.

Abstract: The Minisci alkylation of N-heteroarenes with unactivated alkanes under external oxidant-free conditions provides an economically attractive route to access alkylated N-heteroarenes but remains underdeveloped. Herein, a new electrophotocatalytic strategy to access alkyl radicals from strong C(sp3 )-H bonds was reported for the following Minisci alkylation reactions in the absence of chemical oxidants. This strategy realized the first example of cerium-catalyzed Minisci alkylation reaction directly from abundant unactivated alkanes with excellent atom economy. It is anticipated that the general design principle would enrich catalytic strategies to explore the functionalizations of strong C(sp3 )-H bonds under external oxidant-free conditions with H2 evolution.

Abstract: Peroxidase‐mimicking nanozymes have been extensively studied, however, their application is limited by the requirement for an acidic pH. Herein, the development of Co‐doped mesoporous cerium oxide (Co‐m‐ceria) is reported, which operates optimally at a near‐neutral pH and exhibits a peroxidase‐like catalytic efficiency that is 600‐times higher than that of pristine m‐ceria. Density functional theory (DFT) calculations for the application of pristine and various metal‐doped m‐ceria in peroxidase‐like reactions under different pH environments are conducted to select Co as the appropriate dopant. The high peroxidase‐like activity of Co‐m‐ceria under neutral conditions and its mesoporous nature enable its application in a one‐pot cascade reaction system, wherein biomarkers of oxidative enzymes can be detected without altering the pH. Five different oxidative enzymes are immobilized in the pores of Co‐m‐ceria at high loadings, followed by incorporation of the enzyme‐containing Co‐m‐ceria in paper microfluidic devices for the convenient and simultaneous detection of multiple biomarkers. The Co‐m‐ceria‐incorporated paper microfluidic device enables the selective and sensitive determination of multiple biomarkers using a smartphone‐acquired image. This study demonstrates the potential of the rational design of nanozymes and their application in paper microfluidic devices, laying the groundwork for future applications of nanozymes in point‐of‐care testing environments.

Abstract: Heterogeneous photocatalysis is a promising environmentally friendly strategy for removing contaminants of emerging concern from water, with titanium dioxide being the most studied and exploited photocatalyst, thanks to its good optical and electrical properties. However, one of the main drawbacks linked to its use is the limited absorption of sunlight; several strategies have been explored to enhance the absorption in visible light region and, among them, the doping with elements belonging to the lanthanoid series is particularly attractive. This review focuses on these systems analysing the cases of Cerium, Europium and Erbium doped TiO2 and giving an overview on the structural, optical and electronic characteristics of these materials. Synthesis procedures, inserted dopant percentages, structural and optical properties and the main operating conditions adopted in the photodegradation studies are considered. Particular attention is devoted to unravel the effect induced by the introduction of lanthanoids on the energy gap, on the recombination rate of photogenerated electron-hole pairs and on the inhibition of phase transition from anatase to rutile.

Abstract: Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium is presumed to be a major mechanism of its beneficial action. However, despite some encouraging results, the overall data are somewhat confusing with seemingly the same compounds yielding opposing results. Despite this, cerium nitrate is currently used in wound treatment in combination with silver sulfadiazine as Flammacérium. Cerium oxide, especially in nanoparticle form (Nanoceria), has lately captured much interest due to its antibacterial properties mediated via oxidative stress, leading to an increase of published reports. The properties of Nanoceria depend on the synthesis method, their shape and size. Recently, the green synthesis route has gained a lot of interest as an alternative environmentally friendly method, resulting in production of effective antimicrobial and antifungal nanoparticles. Unfortunately, as is the case with antibiotics, emerging bacterial resistance against cerium-derived nanoparticles is a growing concern, especially in the case of bacterial biofilm. However, diverse strategies resulting from better understanding of the biology of cerium are promising. The aim of this paper is to present the progress to date in the use of cerium compounds as antimicrobials in clinical applications (in particular wound healing) and to provide an overview of the mechanisms of action of cerium at both the cellular and molecular level.

Abstract: Titanium-substituted cerium-oxo-based UiO MOFs with terephthalate linkers modified by various groups (–Br, –NH2, –NO2) or their derivatives (N-heterocyclic or biphenyl groups) were combined with titanium dioxide in a multistep route to obtain a core-shell-like architecture. DFT simulations showed that Ce- and bimetallic Ti/Ce-MOFs exhibited different charge compensation. Extended characterization revealed the formation of heterojunctions between the (Ti/Ce)UiO-X MOFs and TiO2 nanoflowers, suitable band edge positions, and high specific surface area and porosity, which resulted in effective electron transfer and excellent photocatalytic activity. The photoactivity of the (Ti/Ce)[email protected]2 composites for hydrogen production or phenol degradation varied according to the order –NH2 > biphenyl > –N– > –H > –Br > –NO2 > pristine TiO2 or –Br > –NH2 > –NO2 > –N– > –H > biphenyl > pristine TiO2. The photocatalytic hydrogen production rate of (Ti/Ce)UiO-66-NH2@TiO2 was 4724 and 19.3 μmol·gcat–1 after 4 h of UV–Vis and visible light irradiation, which were 79 and 19 times higher than that of pristine rutile, respectively.

Abstract: Aluminum is an attractive anode material in aqueous multivalent‐metal batteries for large‐scale energy storage because of its high Earth abundance, low cost, high theoretic capacity, and safety. However, state‐of‐the‐art aqueous aluminum‐ion batteries based on aluminum anode persistently suffer from poor rechargeability and low coulombic efficiency due to irreversibility of aluminum stripping/plating and dendrite growth. Here eutectic aluminum‐cerium alloys in situ grafted with uniform ultrathin MXene (MXene/E‐Al97Ce3) as flexible, reversible, and dendrite‐free anode materials for rechargeable aqueous aluminum‐ion batteries is reported. As a result of the MXene serving as stable solid electrolyte interphase to inhibit side reactions and the lamella‐nanostructured E‐Al97Ce3 enabling directional Al stripping and deposition by making use of symbiotic α‐Al metal and intermetallic Al11Ce3 lamellas, the MXene/E‐Al97Ce3 hybrid electrodes exhibit reversible and dendrite‐free Al stripping/plating with low voltage polarization of ± 54 mV for ≥1000 h in a low‐oxygen‐concentration aqueous aluminum trifluoromethanesulfonate (Al(OTF)3) electrolyte. These superior electrochemical properties endow soft‐package aluminum‐ion batteries assembled with MXene/E‐Al97Ce3 anode and AlxMnO2 cathode to have high initial discharge capacity of ≈360 mAh g−1 at 1 A g−1, and retain ≈85% after 500 cycles, along with the coulombic efficiency of as high as 99.5%.

Abstract: The high-level contamination of pharmaceuticals in aquatic environment, and their toxicities is a serious issue. This review highlights the use of ceria photocatalyst for treatment of pharmaceuticals. Cerium oxide (CeO 2 ) with high oxygen storage, ecofriendly properties, reusability, and photostability contrary to other metal oxides photocatalysts is reportedly a better choice. However, ceria with high band gap energy show photoactivity mainly under UV light. This review highlights pharmaceuticals contamination in water, their contamination level, and toxicities and properties of CeO 2 and different approaches used for extending photoactivity of CeO 2 under visible irradiation. Metals and non-metals doping is found to promote greatly photoactivity of CeO 2 under visible irradiation by narrowing band gap, shift in absorption edge to visible region, crystal defects and yield of oxygen vacancy, lower recombination of conduction band electrons and valence band holes and increasing surface area. The visible irradiation of CeO 2 is found to produce hydroxyl radical ( OH) and superoxide radical (O 2 – ) which contribute in pharmaceuticals degradation. The electron paramagnetic resonance spectroscopy and radical scavenger studies confirmed the formation of reactive oxygen species from CeO 2 photoactivation. Doping was found to incorporate into the lattice of CeO 2 and improve reusability and stability of CeO 2 photocatalyst. The suggested mechanisms involved in the treatment of pharmaceuticals through OH and O 2 – is discussed. Furthermore, the outlook and future challenges in the use CeO 2 for photocatalytic degradation of pharmaceuticals and other organic pollutants are evaluated. • The sources and issues of different pharmaceuticals in water are discussed. • The design and importance of CeO 2 for degradation under visible light is discussed. • Key steps and processes in the modification and activation of CeO 2 are discussed. • Effects of different factors affecting performance of the photocatalyst is discussed. • Steps necessary for future perspective and potential use of CeO 2 are discussed.

Abstract: Porous, defective, gray cerium oxide (g-CeO2–x) microspheres 4.8 μm in size were synthesized as a multifunctional nanozyme with catalase-, peroxidase-, and oxidase-like activities by the reduction of monodisperse-porous cerium oxide (CeO2) microspheres. Higher Ce(III) atomic fraction, more oxygen vacancy, and lower oxygen content on the surface of g-CeO2–x microspheres were shown by Raman and X-ray photoelectron spectroscopy. Band gap energies of plain CeO2 and g-CeO2–x microspheres were determined as 3.0 and 2.4 eV, respectively. Reactive oxygen species (ROS) related to the enzyme-mimetic activity of g-CeO2–x microspheres were determined as singlet oxygen (1O2•) and superoxide anion (•O2–) by ESR spectroscopy. Michaelis–Menten plots sketched for catalase-, peroxidase-, and oxidase-like activities provided superior maximum substrate consumption rates for g-CeO2–x microspheres. Oxidase- and peroxidase-like activities were used for developing colorimetric and fluorometric protocols for the detection of nitrite as a common pollutant, respectively. g-CeO2–x microspheres also exhibited a photothermal response explained by enhanced light adsorption originated from more oxygen vacancies. A temperature elevation up to 19 °C was obtained under near infrared laser irradiation at 808 nm. Photothermal response accompanying with multifunctional enzyme-mimetic activities makes the porous nanozyme a promising synergistic therapy agent capable of overcoming hypoxia and generating additional ROS in a tumor microenvironment.

Abstract: There has been an explosion of interest toward incorporating graphene-based nanomaterials for corrosion protective coatings. In this study, tannic acid (TA) was employed as a green reducing agent of graphene oxide (TA-rGO) to provide promising nanoplatforms with good dispersion in an epoxy matrix for enhanced mechanical and anti-corrosion properties. In addition, these nanoplatforms were doped with cerium cations (Ce@TA-rGO) to improve active corrosion protection. The designed nanosheets were characterized by several techniques, including FT-IR, XRD, UV–visible, FE-SEM/EDS, TEM, TGA , and XPS. TA improved the thermal properties of graphene oxide significantly with only 40% weight loss up to 800 °C. Furthermore, EIS studies revealed that introducing Ce@TA-rGO nanoplatforms into epoxy coating led to ∼71.5% improvement in active corrosion protection in a saline solution due to the smart release of Ce 3+ . In addition, Ce@TA-rGO nanoplatforms presented excellent barrier properties without electrolyte diffusion after 10 weeks of immersion. In terms of mechanical properties, Ce@TA-rGO-EP and TA-rGO-EP nanocomposites showed higher cross-linking densities and tensile strengths than unfilled epoxy, originating from improvement in the level of dispersion and interaction of nanoplatforms with the polymer.

Abstract: The catalytic conversion of CO2 to CO by the reverse water gas shift (RWGS) reaction followed by well-established synthesis gas conversion technologies could be a practical technique to convert CO2 to valuable chemicals and fuels in industrial settings. For catalyst developers, prevention of side reactions like methanation, low-temperature activity, and selectivity enhancements for the RWGS reaction are crucial concerns. Cerium oxide (ceria, CeO2) has received considerable attention in recent years due to its exceptional physical and chemical properties. This study reviews the use of ceria-supported active metal catalysts in RWGS reaction along with discussing some basic and fundamental features of ceria. The RWGS reaction mechanism, reaction kinetics on supported catalysts, as well as the importance of oxygen vacancies are also explored. Besides, recent advances in CeO2 supported metal catalyst design strategies for increasing CO2 conversion activity and selectivity towards CO are systematically identified, summarized, and assessed to understand the impacts of physicochemical parameters on catalytic performance such as morphologies, nanosize effects, compositions, promotional abilities, metal-support interactions (MSI) and the role of selected synthesis procedures for forming distinct structural morphologies. This brief review may help with future RWGS catalyst design and optimization.