CeO2 Nanorods Research Articles

Designing oxygen vacancy rich mesoporous CeO2 nanorods with co-doped Cd and Ni for synergistic oxidative‑hydrogenation desulfurization of transportation fuel oils

Photocatalytic oxidative coupled in situ hydrogenation is an emerging and alternative route to the traditional costly hydrodesulfurization strategy for the eradication of organosulfur compounds from transportation fuels under mild operating conditions. In this study, Cd/Ni-doped CeO2 catalysts were prepared by improved hydrothermal method, and were in turn applied for the ultra-deep desulfurization of highly resilient 4,6-dimethyldibenzothiophene (4,6-DMDBT) from diesel oil under visible light irradiation. The prepared photocatalyst were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infra-red (FTIR) spectroscopy, ultra-violet visible (UV–vis) spectroscopy and Brauner-Emmette-Teller (BET) analyses. Characterization results revealed that bimetallic doped CeO2 mesoporous nanorods were of uniform size (length: 100–200 nm and width: 30–40 nm) having different oxygen vacancies. Catalytic activity evaluation results revealed that under visible light irradiation, 20%Cd/Ni@CeO2 achieved 100% desulfurization performance of 4,6-DMDBT within 50 min at 60 °C, thus surpassing many state of the art catalysts reported in literature. Cd/Ni@CeO2 remained highly active after 10 successive reuses with rapid recovery by simple washing and filtration. Based on the experimental and characterization results, a suitable reaction mechanism was speculated for the photocatalytic desulfurization of 4,6-DMDBT using Cd/Ni@CeO2.

One dimensional CeO2 nanorods/poly(ethylene oxide) solid composite electrolyte for all-solid-state lithium-ion batteries

The research of poly(ethylene oxide) (PEO)-based solid composite electrolyte with high ionic conductivity and excellent interfacial stability is the key to the development of all-solid-state lithium-ion batteries (ASSLIBs). Herein, uniform nanorod structured CeO2 fillers were controllably synthesized by electrospinning, which were subsequently filled into PEO polymer to prepare CeO2/PEO solid composite electrolyte. The addition of CeO2 nanorods can reduce both the glass transition temperature and the melting point of PEO polymer, and also interact with PEO and lithium bis(trifluoromethanesulphonyl)imide (LITFSI) by Lewis acid–base reaction. Therefore, the solid composite electrolyte exhibits a high ionic conductivity of 4.52 × 10−4 S/cm, a wide electrochemical stability window of about 4.8 V, and a good interfacial stability with Li at 55 °C. Moreover, the LiFePO4/Li ASSLIB divulges the discharging specific capacity of 165, 162, 156 and 146 mA⋅h/g at 0.2, 0.5, 1 and 2 C, respectively, and achieves the capacity retention of 90.3% after 150 cycles at 0.5 C. Consequently, one dimensional CeO2 nanorods can be considered as an alternative filler for polymeric solid electrolyte.

Boosting electrochemical CO2 reduction via valence state and oxygen vacancy controllable Bi–Sn/CeO2 nanorod

Electrocatalytic CO2 reduction reaction (CO2RR) to produce formate has been recognized as one of the most efficient strategies to convert CO2 to energy-rich products and store renewable energy compared with other methods such as biological reduction, thermal catalytic reduction, and photocatalytic reduction. Developing an efficient catalyst is crucial to enhance the formate Faradaic efficiency (FEformate) and retard the competing H2 evolution reaction. The combination of Sn and Bi has been demonstrated to be effective in inhibiting the evolution of H2 and the generation of CO, promoting the formation of formate. Herein, we design Bi- and Sn-anchored CeO2 nanorods catalysts with the valence state and oxygen vacancy (Vo) concentration controllable for CO2RR by reduction treatment at different environments. The m-Bi1Sn2Ox/CeO2 with moderate H2 composition reduction and suitable Sn/Bi molar ratio achieves a remarkable FEformate of 87.7% at −1.18 V vs. RHE compared with other catalysts. Additionally, the selectivity of formate was maintained over 20 h with an outstanding FEformate of above 80% in 0.5 M KHCO3 electrolyte. The outstanding CO2RR performance was attributed to the highest surface Sn2+ concentration which improves the formate selectivity. Further, the electron delocalization effect between Bi, Sn, and CeO2 tunes electronic structure and Vo concentration, promoting the CO2 adsorption and activation as well as facilitating the formation of key intermediates HCOO* as evidenced by the in-situ Attenuated Total Reflectance-Fourier Transform Infrared measurements and Density Functional Theory calculations. This work provides an interesting measure for the rational design of efficient CO2RR catalysts via valence state and Vo concentration control.

In situ synthesis of Cu nanoclusters/CeO2 nanorod as aggregated induced ECL probe for triple-negative breast cancer detection

Cu nanoclusters (NCs) have attracted a lot of attention due to the excellent properties. However, the low luminescence and poor stability limited the Cu NC-based sensing research. In this work, Cu NCs were in situ synthesized on CeO2 nanorods. On the one hand, the aggregated induced electrochemiluminescence (AIECL) of Cu NCs has been observed on the CeO2 nanorods. On the other hand, the substrate of CeO2 nanorods acted as catalysis, which reduced the excitation potential and further enhanced the ECL signal of Cu NCs. It was noticed that CeO2 nanorods also greatly improved the stability of Cu NCs. The resulted high ECL signals of Cu NCs can be kept constant for several days. Furthermore, MXene nanosheets/Au NPs has been employed as electrode modification materials to construct the sensing platform to detect miRNA-585–3p in triple negative breast cancer tissues. Au NPs@MXene nanosheets not only enlarged the specific interface area of the electrodes and the number of reaction sites, but also modulated electron transfer to amplify the ECL signal of Cu NCs. The biosensor had a low detection limit (0.9 fM) and a wide linear range (1 fM to 1 μM) for the detection of miRNA-585–3p in the clinic tissues.

Facile synthesis of Z-scheme CeO2@AgBr heterojunction for improved dye degradation

CeO2 nanorods were synthesized by the hydrothermal method and coupled with AgBr via deposition approach. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmet-Teller (BET) and diffuse reflection spectroscopy (DRS) were used to characterize the structure, morphology and optical properties of the samples. The photoinduced charge separation efficiency was determined by transient photocurrent response and photoluminescence (PL) spectra. The effect of CeO2 loading on the Rhodamine B (RhB) degradation in CeO2@AgBr composites was also investigated. The results indicated that 40 wt%-CeO2@AgBr photocatalyst demonstrated the highest photocatalytic activity than pure CeO2 and AgBr. The trapping experiment showed that holes (h+) and superoxide radicals (•O2−) were the main active species for the degradation of RhB. The improved photocatalytic activity of CeO2@AgBr catalysts were attributed to the formation of Z-scheme heterojunction, which effectively inhibited the recombination of photoinduced electron-hole pairs.

Comparative analysis of the effect of post-annealing on CeO2 and DC Magnetron Sputtered WO3/ CeO2 nanorods thin films for smart windows

This study investigates and evaluates thin films of WO3 (Tungsten Oxide) coated CeO2 (Cerium Oxide) Nanostructure (NR) for electrochromic applications. Using CH4N2O (Urea) and Ce(NO3)3.6H2O (Cerium Nitrate Hexahydrate) on a fluorine-doped tin oxide (FTO) base, cerium oxide nanorods were produced hydrothermally. Cerium Oxide nanorods were coated with a thin coating of WO3 using DC magnetron sputtering under argon gas at room temperature. In a three-electrode electrochemical system, thin sheets of manufactured WO3/CeO2 nanorods (NRs) served as the working electrode, saturated Hg/HgCl2 served as the reference electrode, and platinum wire served as the counter electrode. To produce the 0.5 M electrolyte, the H2SO4 solution was diluted in deionized (DI) water. Electrochromic tests revealed a 12.15 cm2/C coloring efficiency for annealed 10 µL HCl CeO2/WO3 film. A scanning electron microscope (SEM), an electrochemical analyzer, an X-ray diffraction spectrometer, and an ultraviolet-visible spectrometer were used to study the optical properties, composition, surface morphology, and electrochromic property of the generated thin films. Due to its high charge capacity and optical transmission properties, CeO2 nanorods with WO3 coating have proven to be a practical material for electrochromic devices (ECD).

α-Fe2O3/CeO2 S-scheme heterojunction photocatalyst for enhanced photocatalytic H2 evolution

High photo-stability and effective charge separation are pivotal for hydrogen production over the photocatalysts through solar energy. Here mesoporous CeO2 nanorods were hydrothermally synthesized using cetyltrimethyl ammonium bromide and tetrapropylammonium hydroxide as the template to construct the novel S-scheme heterojunction α-Fe2O3/CeO2 photocatalyst. The obtained heterojunction Fe2O3/CeO2 photocatalyst exhibited outstanding enhanced H2 evolution under visible illumination. The XRD results indicated that the Fe2O3/CeO2 nanocomposites revealed rhombohedral α-Fe2O3 and cubic CeO2 structures without impurities. TEM images revealed the formation of CeO2 nanorods with 400 nm length and 20 nm width decorated with Fe2O3 NPs (10 nm). The optimized S-scheme Fe2O3/CeO2 nanocomposites displayed a superior photocatalytic H2 evolution rate of 2973.2 µmolg−1h−1, which was promoted 5.43 folds greater than that of CeO2 nanorods (547.05 µmolg−1h−1). The electron transport channels in S-scheme Fe2O3/CeO2 nanocomposites interfacial junctions facilitated the directional migration spatial and separation of photocarriers. The H2 evolution rate over the obtained Fe2O3/CeO2 photocatalyst was significantly promoted due to its synergistic effect, porous architecture, oxygen vacancies, small particle size and high visible light absorption ability. There was no decrease in the H2 evolution rate after five cycles of photocatalytic H2 evolution, which could verify the durability and stability of the Fe2O3/CeO2 nanocomposite. The photoluminescence (PL) and electrophotochemical responses were conducted to determine the charge carriers separation rate and understand the photocatalytic mechanism.

Bimetallic AuPt alloy/rod-like CeO2 nanojunctions with high peroxidase-like activity for colorimetric sensing of organophosphorus pesticides.

Organophosphorus pesticides (OP) have extensive applications in agriculture, while their overuse causes inevitable residues in food, soil, and water, ultimately being harmful to human health and even causing diverse dysfunctions. Herein, a novel colorimetric platform was established for quantitative determination of malathion based on peroxidase mimic AuPt alloy decorated on CeO2 nanorods (CeO2@AuPt NRs). The synthesized nanozyme oxidized colorless 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. Besides, the oxidized TMB was inversely reduced by ascorbic acid (AA), which were originated from hydrolysis of L-ascorbic acid-2-phosphate (AA2P) with the assistance of acid phosphatase (ACP). Based upon this observation ACP analysis was explored by colorimetry, showing a wid linear range of 0.2 ~ 3.5 U L-1 and a low limit of detection (LOD = 0.085 U L-1, S/N = 3). Furthermore, malathion present in the colorimetric system inhibited the activity of ACP and simultaneously affected the generation of AA, in turn promoting the recovery of the chromogenic reaction. Based on this, the LOD was decreased to 1.5nM (S/N = 3) for the assay of malathion with a wide linear range of 6 ~ 100nM. This simple colorimetric platform provides some informative guidelines for determination of other pesticides and disease markers.

Au/CeO2 NR Restricted Inside Cu-MOFs: A Three-in-One Artificial Enzyme with Synergistically Enhanced Peroxidase-Like Activity for Dual-Mode Sensing of Multiple Biomarkers

Nanomaterials with inherent enzyme-mimetic properties have been extensively studied in biosensing field, but it is still challenging to overcome their natively weak enzyme-mimetic activity and further promote their stabilities. In this work, a three-in-one artificial enzyme with synergistically enhanced peroxidase-like activity and outstanding stability is constructed by restricting Au-loaded CeO2 nanorods (NR) (1% Au:CeO2 mass ratio) inside Cu-based metal–organic frameworks (Cu(PABA)), termed Au1/CeO2 NR@Cu(PABA). It has been demonstrated that the artificial enzyme possesses significantly improved performance in catalytic decomposition of H2O2, with ∼2.41 and ∼1.49 times higher activity than its individual constituents (Au1/CeO2 NR and Cu(PABA)), benefiting from the synergistic effect and the unique restricted structure; owns strong affinities to substrates, with separately ∼8.21- and ∼3.13-fold lower Michaelis constants toward H2O2 and o-phenylenediamine, respectively, than horseradish peroxidase; and exhibits desirable pH (4–12), thermal (30–80 °C), organic solvent (N,N-dimethylformamide, acetone, methanol, etc.), and long-term storage (30 days) stabilities, advantaging practical applications. Taking aforementioned superior properties of Au1/CeO2 NR@Cu(PABA), a universal colorimetric/fluorometric dual-mode sensing platform is built and utilized for detection of biomarkers (e.g., glucose, galactose, and cholesterol) in biological fluids with satisfactory recoveries (90.2–108%). This work offers new horizons in designing high-efficiency, stable, and credible biomimetic catalysts to accelerate future advanced engineering of nanozymes.

Enhanced selective separation of vanadium(V) and chromium(VI) using the CeO2 nanorod containing oxygen vacancies.

Adsorption of vanadium from wastewater defends the environment from toxic ions and contributes to recover the valuable metal. However, it is still challenging for the separation of vanadium (V5+) and chromium (Cr6+) because of their similar properties. Herein, a kind of CeO2 nanorod containing oxygen vacancies is facilely synthesized which displays ultra-high selectivity of V5+ against various competitive ions (i.e., Fe, Mn, Cr, Ni, Cu, Zn, Ga, Cd, Ba, Pb, Mg, Be, and Co). Moreover, a large separation factor (SFV/Cr) of 114,169.14 for the selectivity of V5+ is achieved at the Cr6+/V5+ ratio of 80 with the trace amount of V5+ (~ 1mg/L). The results show that the process of V5+ uptake is the monolayer homogeneous adsorption and is controlled by external and intraparticle diffusions. In addition, it also shows that V5+ is reduced to V3+ and V4+ and then formation of V-O complexation. This work offers a novel CeO2 nanorod material for efficient separation of V5+ and Cr6+ and also clarifies the mechanism of the V5+ adsorption on the CeO2 surface.

Interfacial Synergy between the Cu Atomic Layer and CeO2 Promotes CO Electrocoupling to Acetate

Cu is considered to be an effective electrocatalyst in CO/CO2 reduction reactions (CORR/CO2RR) because of its C-C coupling into C2+ products, but it still remains a formidable challenge to rationally design Cu-based catalysts for highly selective CO/CO2 reduction to C2+ liquid products such as acetate. We here demonstrate that spraying atomically layered Cu atoms onto CeO2 nanorods (Cu-CeO2) can lead to a catalyst with an enhanced acetate selectivity in CORR. Owing to the existence of oxygen vacancies (Ov) in CeO2, the layer of Cu atoms at interface coordinates with Ce atoms in the form of Cu-Ce (Ov), as a result of strong interfacial synergy. The Cu-Ce (Ov) significantly promotes the adsorption and dissociation of H2O, which further couples with CO to selectively produce acetate as the dominant liquid product. In the current density range of 50-150 mA cm-2, the Faradaic efficiencies (FEs) of acetate are over 50% with a maximum value of 62.4%. In particular, the turnover frequency of Cu-CeO2 reaches 1477 h-1, surpassing that of Cu nanoparticle-decorated CeO2 nanorods, bare CeO2 nanorods, as well as other existing Cu-based catalysts. This work advances the rational design of high-performance catalysts for CORR to highly value-added products, which may attract great interests in diverse fields including materials science, chemistry, and catalysis.

Au Nanoparticles Supported on Mn- or/and La-Doped CeO2 Nanorods for One-Step Oxidative Esterification of Methacrolein and Methanol to Methyl Methacrylate

Mn- or/and La-doped CeO2 nanorods supporting Au catalysts were prepared using the hydrothermal method and deposition precipitation (DP) method and applied to the direct oxidative esterification of methacrolein (MAL) and methanol into methyl methacrylate (MMA). Various characterization techniques such as N2-physical adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (TPR) and CO2 temperature programmed desorption (TPD) were utilized to analyze the structural properties, reducibility and basicity of Au catalysts. The catalyst with Mn doping only showed the best performance, and particularly the highest conversion, while the catalyst with Mn and La doping showed the highest selectivity.

Applying CeO2 nanorods in flexible electrochemical immunosensor to detect C-reactive protein

In this work, we report the development of a flexible electrochemical immunosensor based on CeO2 nanorods (NRs) immobilized with C-reactive protein (CRP) antibody, a biomarker of cardiovascular disease. CeO2 NRs were obtained by microwave-assisted hydrothermal method and characterized by XRD, TEM, and XPS. For the preparation of the working electrode, WE, of the immunosensor, the NRs were dispersed in organic solvent and then functionalized with cystamine and glutaraldehyde, and then modified with CRP antibody. The deposition condition was evaluated for electrode functionalization and immobilization. Functionalization and immobilization were verified by spectroscopic techniques and proved effective repeatability and reproducibility. The developed immunosensor had acceptable reproducibility (coefficient of variation = 4.5 %), allowed detection in the range of 0.3 to 7.0 mg L−1 of CRP with a detection limit of 0.18 mg L−1, and applications that are immediately detectable, easy-to-handle, low-cost and ideal for point-of-care.

Enhanced hybrid photocatalytic dry reforming using a phosphated Ni-CeO2 nanorod heterostructure

Operating the dry reforming reaction photocatalytically presents an opportunity to produce commodity chemicals from two greenhouse gases, carbon dioxide and methane, however, the top-performing photocatalysts presented in the academic literature invariably rely on the use of precious metals. In this work, we demonstrate enhanced photocatalytic dry reforming performance through surface basicity modulation of a Ni-CeO2 photocatalyst by selectively phosphating the surface of the CeO2 nanorod support. An optimum phosphate content is observed, which leads to little photoactivity loss and carbon deposition over a 50-hour reaction period. The enhanced activity is attributed to the Lewis basic properties of the PO43− groups which improve CO2 adsorption and facilitate the formation of small nickel metal clusters on the support surface, as well as the mechanical stability of CePO4. A hybrid photochemical-photothermal reaction mechanism is demonstrated by analyzing the wavelength-dependent photocatalytic activities. The activities, turnover numbers, quantum efficiencies, and energy efficiencies are shown to be on par with other dry-reforming photocatalysts that use noble metals, representing a step forward in understanding how to stabilize ignoble nickel-based dry reforming photocatalysts. The challenges associated with comparing the performance of photocatalysts reported in the academic literature are also commented on.

Understanding structure-performance relationships of CoOx/CeO2 catalysts for NO catalytic oxidation: Facet tailoring and bimetallic interface designing

Crystalline structure and bimetallic interaction of metal oxides are essential factors to determine the catalytic activity. Herein, three different CoOx/CeO2 catalysts, employing CeO2 nanorods (predominately exposed {110 facet), CeO2 nanopolyhedra ({111} facet) and CeO2 nanocubes ({100} facet) as the supports, are successfully prepared for investigating the effect of exposed crystal facets and bimetallic interface interaction on NO oxidation. In comparison with the {111} and {100} facets, the exposed crystal facet {110} exists the best superiority to anchor and stabilize Co species. Moreover, ultra-small CoOx clusters composed of strong Co-O coordination shells with minor Co-O-Ce interaction are formed and uniformly dispersed on the CeO2 nanorods. Structural characterizations reveal that the active exposed crystal facet {110} and the strong bimetallic interface interaction in CoOx/CeO2-nanorods (R-CC) result in more structural defect, endowing it with abundant oxygen vacancies, excellent reducibility and strong adsorption capacity. The DRIFTs spectra further indicate that the exposed crystal facet {110} has a significant promoting effect on the strength of nitrates compared with {111} and {100} facets. The bimetallic interface interaction not only significantly facilitates the formation of nitrate species at lower temperature, but also effectively suppresses the generation of sulfate and lower the sulphation rate. Therefore, R-CC catalyst exhibits the maximum NO oxidation activity with the conversion of 86.4 % at 300 °C and still sustains its high activity under cyclic condition or 50 ppm SO2. The provided crystalline structure and interaction-enhanced strategy sheds light on the design of high-activity NO oxidation catalysts.

Effects of Molybdenum Doping on the Enhanced Electrocatalytic Nitrogen Reduction Reaction Performance of CeO2 Nanorods: Theoretical and Experimental Investigations.

As a green and sustainable strategy, the electrocatalytic N2 reduction reaction (NRR) has been considered the best potential approach to replace the traditional Haber-Bosch process under ambient conditions. The key is to exploit efficient and low-cost electrocatalysts according to the current situation. Herein, a series of Molybdenum (Mo) doped CeO2 nanorods (NR) catalysts were successfully fabricated via a hydrothermal reaction coupled with high temperature calcination. The nanorod structures were not altered after Mo atom doping. The obtained 5 %-Mo-CeO2 nanorods act as a superior electrocatalyst in neutral electrolytes of 0.1 M Na2 SO4 . Such electrocatalyst significantly enhances NRR performance with an NH3 yield of 10.9 μg h-1 mg-1 cat at -0.45 V vs reversible hydrogen electrode (RHE) and a Faradaic efficiency (FE) of 26.5 % at -0.25 V vs RHE. That outcome is 4 times higher than that of CeO2 nanorods (2.6 μg h-1 mg-1 cat ; 4.9 %). Meanwhile, density functional theory (DFT) calculation shows the characteristics after Mo doping: the band gap value lowers, the density of states increases, electrons are more easily excited, and N2 molecules are more easily adsorbed, thereby enhancing the activity of the electrocatalytic NRR.

Thermocatalytic Decomposition of Dimethyl Methylphosphonate Based on CeO2 Catalysts with Different Morphologies

The catalytic performances of the catalysts and decomposition mechanisms of dimethyl methylphosphonate (DMMP), a commonly used nerve agent simulant, are well understood based on previous studies. However, the effects of the morphology of the catalyst on DMMP decomposition performance and mechanisms remain unexplored. Thus, in this work, experimental studies were conducted on the thermocatalytic decomposition of DMMP on CeO2 nanomaterials with different morphologies, e.g., irregular nanoparticles, nanorods, and nanocubes. From the performance evaluation, CeO2 nanorods exhibited higher DMMP thermocatalytic decomposition performance as compared to irregular nanoparticles and nanocubes. The primary reaction pathways were the same on all three morphologies of materials, according to in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study, whereas side reaction paths showed variable behaviors. According to the catalytic reaction mechanism study, the surface lattice oxygen played a vital role in the thermocatalytic decomposition of DMMP and the accumulation of phosphates, carbonates, and formates were the main factors for deactivation of the catalyst. The behavior of CeO2 catalyst with different morphologies in the thermocatalytic decomposition of DMMP was revealed in this work, and this will be useful for the future design of high-performing catalysts for the efficient degradation of chemical toxicant.

1D/2D SnO2/SnS2 heterojunctions coupling with PtPd/CeO2 heterostructured nanozyme for ultrasensitive PEC apatasensing of lincomycin

Lincomycin (LIN), as one of antibiotics, is often present in feed and animal products, whose abuse would cause serious side effects for human health or even death. Thus, its screening and quantitative assay is crucial in diverse matrix. Herein, SnO2 nanorods were efficiently anchored on SnS2 nanosheets to form the 1D/2D SnO2/SnS2 heterojunctions, coupled by illuminating the enhanced PEC mechanism. In parallel, tiny PtPd nanoparticles (NPs) were in situ grown on CeO2 nanorods (termed PtPd/CeO2), whose peroxidase-like property was carefully investigated by 3,3′,5,5′-tetramethylbenzidin oxidation in the presence of H2O2. Based on the above foundation, a novel photoelectrochemical (PEC) aptasensor was built for assay of LIN, coupled with the home-made PtPd/CeO2 heterostructured nanozyme for signal amplification via catalytic oxidation of 3,3′-diaminobenzidine to generate insoluble precipitates on the SnO2/SnS2 photoanode. The resultant biosensor had a wider linear range of 0.001 ∼ 100 nM and a lower limit of detection (LOD) of 0.75 pM (S/N = 3). This study provides some constructive insights for bioanalysis of antibiotics in actual environment and food samples.

Construction of Ag-modified ZnO–CeO2 2D-1D S-scheme heterojunction photocatalyst with phenomenal photocatalytic performance for H2 evolution

The rational design of S-scheme heterojunctions is a promising strategy to boost the spatial separation of photocarriers and optimize the stability of the heterosystem. Herein, we successfully designed a 2D-1D ZnO–CeO2–Ag plasmonic heterosystem containing ZnO nanosheets and CeO2 nanorods through the solvothermal process. The ZnO–CeO2–Ag exhibits the maximum photocatalytic H2 evolution rate of 31420 μmol h−1 g−1 under simulated sunlight exposure, which is about 55 and 14 times superior to pure ZnO and CeO2, respectively. The notably high photocatalytic efficiency of ZnO–CeO2–Ag is primarily assigned to the design of plasmonic S-scheme heterosystem. This heterosystem promotes visible light absorption due to LSPR phenomenon, which enhances the specific surface area and facilitates the built-in electric field-derived S-scheme separation and transference of photocarriers. The H2 evolution activity is also examined by varying different parameters, including catalyst dose, initial pH, nature and quantity of sacrificial reagent, and process time. The H2 evolution rate of ZnO–CeO2–Ag for consecutive cycles confirmed its high stability and reusability. This research paves the way for the design of possible heterojunction photocatalysts for energy production and environmental remediation.

CeO2‐Nanorods‐Catalyzed Protoboration of Alkenes and Alkynes with Bis(pinacolato)diboron

AbstractThe protoboration of alkenes and alkynes with B2pin2 (pin=OCMe2CMe2O) using a heterogeneous CeO2 nanorods catalyst has been developed to afford the corresponding alkyl and vinyl boronate esters in 41–99% yield under mild reaction conditions. A series of aromatic and aliphatic alkenes and alkynes with synthetically important functional groups were well tolerated. In both the systems, the catalyst could be reused for up to six runs without significant loss in activity. Stoichiometric reactions revealed that the protoboration may proceed through the in situ formed catalytically active boryl species.magnified image