Showing papers by "Francis Verpoort published in 2023"

Green Synthesis and Photocatalytic Dye Degradation Activity of CuO Nanoparticles

Abstract: The degradation of dyes is a difficult task due to their persistent and stable nature; therefore, developing materials with desirable properties to degrade dyes is an important area of research. In the present study, we propose a simple, one-pot mechanochemical approach to synthesize CuO nanoparticles (NPs) using the leaf extract of Seriphidium oliverianum, as a reducing and stabilizing agent. The CuO NPs were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and Fourier-transform infrared spectroscopy (FTIR). The photocatalytic activity of CuO NPs was monitored using ultraviolet-visible (UV-Vis) spectroscopy. The CuO NPs exhibited high potential for the degradation of water-soluble industrial dyes. The degradation rates for methyl green (MG) and methyl orange (MO) were 65.231% ± 0.242 and 65.078% ± 0.392, respectively. Bio-mechanochemically synthesized CuO NPs proved to be good candidates for efficiently removing dyes from water.

Formation of Value-Added Cyclic Carbonates by Coupling of Epoxides and CO2by Ruthenium Pincer Hydrazone Complexes under Atmospheric Pressure

Abstract: Transforming atmospheric CO2 into industrially valuable cyclic carbonates is of great importance and one of the attractive approaches for reducing CO2 concentration in the biosphere. However, the selectivity and conversion of ruthenium catalysts for cyclic carbonate formation via CO2 insertion to epoxides are low at high pressure. Here, a series of novel ruthenium complexes supported by ONN pincer-type hydrazone ligands were successfully generated, and their potential for CO2 valorization to cyclic carbonates was investigated. NMR, Fourier transform infrared (FT-IR), mass spectrometry, elemental analysis, and single-crystal diffraction analysis further confirmed the structures of these ruthenium compounds. These compounds were utilized for the CO2/coupling reaction after thorough characterization. Fortunately, these complexes outperform the reported ruthenium catalysts with a turn-over frequency of 833 h–1 and >99% selectivity at atmospheric pressure without any assisted cocatalyst. The designed catalyst showed consistent catalytic performance over five repeating cycles.

Single‐atom metal‐nitrogen‐carbon catalysts energize single molecule detection for biosensing

Abstract: Biosensors featuring single molecule detection present huge opportunities as well as challenges in food safety inspection, disease diagnosis, and environmental monitoring. Single-molecule detection is largely lacking of high enough activity, precision molecule selectivity, and understanding in the exact operating mechanism. Single-atom catalysts (SACs), especially those metals-nitrogen-carbon that mimic the natural metalloenzyme structure, and with well-defined metal atom bond configurations, high level of molecular selectivity, and easy fabrication, endow single molecule detections with practical-use feasibilities. The recent advances in single-atom catalysts also present new pathways in the key mechanism understandings. In this short review, we will first visit the brief history and advantages of SACs that have been explored only recently for molecule-scale biosensors, where they are analogous and also differentiated from those nanozymes and natural metalloenzymes. Their applications in electrochemical, photochemical, and photoelectrochemical sensors are then discussed comprehensively by focusing on the different molecule-scale sensing modes in achieving local coordination-modulated signal amplifications. Finally, we identify new opportunities and challenges faced by these SACs-based single molecule detections in the further development of biosensors.

Rational design of cobalt catalysts embedded in N-Doped carbon for the alcohol dehydrogenation to carboxylic acids

Abstract: In this work, a series of Co catalysts (namely [email protected]) was designed and developed from the thermal treatment of ZIF-67. Through extensive screening of various parameters, [email protected]2/Ar exhibited the best catalytic performance in the acceptorless alcohol dehydrogenation to carboxylic acids. It was worth noting that [email protected]2/Ar enabled the efficient synthesis of various aromatic and aliphatic carboxylic acids in moderate to high yields. Besides, it was recyclable for 9 consecutive cycles without activity decay. Moreover, the effects of pyrolysis conditions on the catalytic performance of the resulting materials were thoroughly examined, and the rationale for the superiority of [email protected]2/Ar over the other prepared materials was also provided. Specifically, the pyrolysis atmosphere applying 95% of Ar gas and 5% of H2 gas (H2/Ar) resulted in the generation of ideal porosity and carbon nanotubes (CNTs), while utilizing 700 °C as the optimized pyrolysis temperature was ascribed to the comprehensive evaluation of materials crystallinity and defective structures. Furthermore, additional insights were gained by systematically exploring the oxidation states of Co in different catalysts. It was proposed that the Co–N species played a crucial role in this catalysis, while the contribution of other Co species, including Co0 and Co–O, could not be neglected. Finally, a plausible reaction mechanism was proposed based on the above observations and related literature reports.

Two-Dimensional SnO2-ZnO Nanohybrid Electrode Fabricated via Atomic Layer Deposition for Electrochemical Supercapacitors

Abstract: Two-dimensional (2D) heterostructures of transition metal oxides (TMOs) are promising candidates for high-performance electrochemical supercapacitors (ESCs). Herein, sub-10 nm 2D SnO2-ZnO heterostructures were constructed on Au-modified SiO2/Si wafers by an atomic layer deposition (ALD) technique for ESC application. The cyclic voltammetry (CV) study revealed the pseudocapacitive-type Faradaic redox reactions of the 2D SnO2-ZnO heterostructure electrode with good reversibility. The electrode exhibited high energy storage capability with a high specific capacitance (Cs) of 538.90 F g–1 at a scan rate and current density of 10 mV s–1 and 8.0 A g–1, respectively. The corresponding energy density and the power density were 14.80 Wh kg–1 and 2512.35 W kg–1, respectively, at 8.0 A g–1. The high energy storage capacity of the heterostructure electrode can be ascribed to the combination of improved infiltration and intercalation/deintercalation of electrolyte ions induced by the nanoscale thickness and enhanced redox activity of the heterostructure. Furthermore, the 2D electrode displayed excellent electrochemical robustness with a capacitance retention of 96.3% after 5000 charge/discharge cycles.

An ode to nanoparticles in catalysis

Abstract: Going down the particle size to nanodomain opens up innovative allies to expedite the physical and chemical properties of materials, and in turn, facilitates the manipulation of their catalytic propensity. Herein, we provide a succinct perspective of the wide spectrum of nanoparticles (NPs) in catalysis highlighting the underlying chemistry of different aspects, the introspective thread connecting them, and the ways to devise operando algorithms for exploiting such inter-connected systems. Following an introductory section discussing the generic miens of NPs, we went on to discuss the role of nanocrystals, especially various crystal facets and morphological anomalies in catalysis. The electronic shuttling involved in these catalysis vis-à-vis surface plasmon effect, Mott–Schottky contact, and Z-scheme systems, all in the nanodomain, was then explained. Following this, we introduced the concept of “Soft Matter” and “Active Matter”, essentially the ones exploiting previously discussed chemistry, and explained the role of their in situ morphological precedence and stimuli-induced motility in catalysis. Finally, the emerging concept of Operando Systems Chemistry Algorithm (OSCA) was instituted discussing the devising strategies of tandem compartmentalized chemical arrays as individual algorithm analogs to sequentially impact the properties of aforementioned soft and active matters for targeted catalytic assays.

Green Approach for Synthesizing Copper-Containing ZIFs as Efficient Catalysts for Click Chemistry

Abstract: ZIF-8 and ZIF-67 containing various percentages of copper were successfully synthesized through a green in-situ thermal (IST) approach based on 2-methylimidazole (2-MIM) as the organic linker. The IST method has several advantages over previously reported studies, including solvent and additive-free reaction conditions, a mild reaction temperature, a single-step procedure, no activation requirements, and the use of the smallest precursor ratio (M/L). The high catalytic performance of Cu/ZIF-8 and Cu/ZIF-67 in click chemistry is attributed to their high specific surface area, excellent porosity, and structural stability. To achieve these features, a range of parameters—such as time, temperature, gas atmosphere, and precursor ratio—were optimized. Several characterization methods were used to confirm the features of the produced catalysts. Overall, the synthesis strategy for achieving the targeted ZIFs with unique features is “green” and does not require further activation or treatment to eliminate side products. This method has great potential for manufacturing metal-organic frameworks on a large scale. Moreover, water was used as a solvent during the click reaction, resulting in high yields and making this an attractive, green, and eco-friendly procedure.

Quantification of the Microwave Effect in the Synthesis of 5-Hydroxymethylfurfural over Sulfonated MIL-101(Cr)

Abstract: The potential benefits of microwave irradiation for fructose dehydration into 5 hydroxymethylfurfural (5-HMF) have been quantified over a sulfonated metal–organic framework (MOF), MIL 101(Cr)-SO3H. The effects of temperature (140–170 °C), batch time (5–300 min), and catalyst-to-substrate ratio (0.1–0.01 g/g) were systematically mapped. After 10 min of microwave (MW) irradiation at 140 °C in a DMSO–acetone reaction medium, practically complete fructose conversion was obtained with a 70% yield of 5-HMF. Without MW, i.e., using conventional heating (CH) at the same conditions, the fructose conversion was limited to 13% without any 5-HMF yield. Rather, 90 min of CH was required to reach a similarly high conversion and yield. The profound impact of moving from CH towards MW conditions on the reaction kinetics, also denoted as the microwave effect, has been quantified through kinetic modeling via a change in the Gibbs free energy of the transition state. The modeling results revealed an eight-fold rate coefficient enhancement for fructose dehydration owing to MW irradiation, while the temperature dependence of the various reaction steps almost completely disappeared in the investigated range of operating conditions.

Thermal Solid–Solid Transformation Synthesis of Zinc Anchored in Hierarchical Porous N-Doped Carbon for Efficient CO2 Applications

Abstract: A facile method was developed from solid precursors to obtain zinc anchored in a nitrogen-doped carbon matrix (Zn-NCx) via the solid–solid thermal (SST) route. The applied method, to synthesize Zn-NCx, was completed under single-step and solvent-free conditions. Regarding the synthesis mechanism, the zeolitic-imidazole framework (ZIF-8) was first fabricated from solid mixed precursors at a low temperature of the SST process. In a continuous mode, the fabricated ZIF-8 was sacrificed at a high temperature of the SST process to obtain Zn-NCx. Detailed characterization was performed to investigate the solid–solid transformation of precursors during the SST route. This characterization confirmed that Zn-NCx consists of zinc anchored in the nitrogen-doped carbon matrix. Also, due to the high porosity and N-functionalization, Zn-NCx exhibited excellent adsorption properties for CO2 and was helpful in CO2/CH4 separation. Furthermore, the chemical properties in hierarchical porous Zn-NCx were demonstrated to act as a catalyst for CO2 fixation. Interestingly, since the current method (SST) is solvent-free, this is a promising environmental route. The procedure has the potential for upscaling, revealing vast prospect for applications based on these carbon materials.

Advances and challenges in designing MXene quantum dots for sensors

Abstract: MXene quantum dots (MQDs) sensor is a promising platform for identifying target analytes by sensing fluorescence, electrochemical signals, photoluminescence, biomedical, and so on. On the way to designing MQDs in the sensors, substantial progress has been made with basic scientific and technological hurdles remaining. Combining specific functional designs of MQDs with mechanistic understanding provides new research prospects and technology opportunities even at the industrial level. However, MQDs must be able to detect target analytes with higher sensitivity, robust stability, and applied compatibility. Here, we review the recent advances and challenges in the synthetic strategies and rational design of MQDs. By zooming in on several representative examples, we discuss the existing potentials of MQDs in the application of fluorescence, electrochemical luminescence, photoluminescence, colorimetric/fluorescent dual-mode, and biomedical sensors. Finally, we identify the opportunities and challenges to further understanding of MQDs sensors.

Amide Functionalized Mesoporous MOF LOCOM-1 as a Stable Highly Active Basic Catalyst for Knoevenagel Condensation Reaction

Abstract: Acyl-amide is extensively used as functional group and is a superior contender for the design of MOFs with the guest accessible functional organic sites. A novel acyl-amide-containing tetracarboxylate ligand, bis(3,5-dicarboxy-pheny1)terephthalamide, has been successfully synthesized. The H4L linker has some fascinating attributes as follows: (i) four carboxylate moieties as the coordination sites confirm affluent coordination approaches to figure a diversity of structure; (ii) two acyl-amide groups as the guest interaction sites can engender guest molecules integrated into the MOF networks through H-bonding interfaces and have a possibility to act as functional organic sites for the condensation reaction. A mesoporous MOF ([Cu2(L)(H2O)3]·4DMF·6H2O) has been prepared in order to produce the amide FOS within the MOF, which will work as guest accessible sites. The prepared MOF was characterized by CHN analysis, PXRD, FTIR spectroscopy, and SEM analysis. The MOF showed superior catalytic activity for Knoevenagel condensation. The catalytic system endures a broad variety of the functional groups and presents high to modest yields of aldehydes containing electron withdrawing groups (4-chloro, 4-fluoro, 4-nitro), offering a yield > 98 in less reaction time as compared to aldehydes with electron donationg groups (4-methyl). The amide decorated MOF (LOCOM-1-) as a heterogeneous catalyst can be simply recovered by centrifugation and recycled again without a flagrant loss of its catalytic efficiency.

Toxicity Evaluation of a Heavy-metal Polluted River: Pollution Identification and Bacterial Community Assessment.

Abstract: The Salt River is an important urban river in Kaohsiung, Taiwan. In this study, the source identification and risk and toxicity assessment of the heavy-metal contaminated sediments in the Salt River were investigated. The geo-accumulation index (Igeo), enrichment factor (EF), sediment quality guidelines (SQGs), potential ecological risk index (RI), pollution load index (PLI), and toxic units (TU) were applied to determine effects of heavy metals on microbial diversities and ecosystems. Results from the ecological and environmental risk assessment show that high concentrations of Zn, Cr, and Ni were detected in the midstream area, the sum of toxic units (ΣTUs) in the midstream (7.2 - 32.0) is higher than in the downstream (14.0 - 19.7) and upstream (9.2 - 17.1). It could be because of the continuous inputs of heavy-meta-contained wastewaters from adjacent industrial parks. Results also inferred that the detected heavy metals in the upstream residential and commercial areas were possibly caused by nearby vehicle emissions, non-point source pollution, and domestic wastewater discharges. Results of metagenomic assays show that the sediments contained significant microbial diversities. Metal-tolerant bacterial phyla (Proteobacteria: 24.4% to 46.4%, Bacteroidetes: 1.3% to 14.8%, and Actinobacteria: 2.3% to 11.1%) and pathogenic bacterial phyla (Chlamydiae: 0.5% to 37.6%, and Chloroflexi: 5.8% to 7.2%) with relatively high abundance were detected. Metal-tolerant bacteria would adsorb metals and cause the increased metal concentrations in sediments. Results indicate that the bacterial composition in sediment environments was affected by anthropogenic pollution and human activities, and the heavy-metal-polluted ecosystem caused the variations in bacterial communities.

Hydrogen Bond-Mediated pH-Universal Electrocatalytic Hydrogen Production by Conjugated Porous Poly-Indigo

Abstract: High-performing catalysts for hydrogen evolution reaction (HER) via water electrolysis are of great importance for producing carbon-free green fuels. Compared to the routinely used metal-based systems under acidic conditions, metal-free...

Inside Back Cover: Carbon Neutralization, Volume 2, Issue 2, March 2023

Abstract: Inside back cover image: MXene quantum dots (MQDs), as a new type of transition metal material, shows good application prospects in the field of sensing. In the article 10.1002/cnl2.47, the application of MQDs in fluorescence, electrochemiluminescence, photoluminescence, colorimetric/fluorescence dual-mode and biomedical sensors was systematically introduced, and its broad prospects in environmental monitoring, gas sensing, human health detection and cancer treatment were summarized. The monitoring of human health and environmental health is realized by using the functionalization of MQDs.