Ternary Catalyst Research Articles

Dual Z-scheme BiOI/Bi2S3/MgIn2S4 composite photocatalyst for effective photocatalytic degradation of Congo red.

The demand and use of dyes in modern life are increasing, and dye pollution has become a widespread concern worldwide; therefore, it is essential to develop novel environmentally friendly materials to deal with dye wastewater. Herein, a novel visible-light-driven ternary catalyst (BiOI/Bi2S3/MgIn2S4) was fabricated by employing the hydrothermal method. Compared to BiOI, the synthesized ternary catalyst exhibited better photocatalytic performance to decompose Congo red under visible light. Congo red was completely degraded after 0.5 h (0.5 g/L photocatalyst BiOI/Bi2S3/MIS-1) in the presence of visible light, which was 16.83 and 9.94 times of that of pure BiOI and MgIn2S4, respectively. A repetitive experiment showed that the BiOI/Bi2S3/MIS-1 could be reusable to degrade Congo red, demonstrating thatit has excellent mechanical properties. The enhanced photocatalytic capability was due to addition of BiOI and Bi2S3, which increased the charge separation as well as suppressed the recombination of photo-induced holes and electrons. Electron paramagnetic resonance technique and free radical trapping tests were employed to determine the radicals produced in BiOI/Bi2S3/MgIn2S4 in the presence of visible light, indicating that ·O2- and h+ were major active species to decompose Congo red under photocatalytic process. Seventeen main intermediates or reaction products were identified by UPLC-MS. The tentative degradation pathway of Congo red was also proposed.

Ni‐Doped RuPt Nanoalloy on Acid‐Treated Carbon for pH‐Universal Hydrogen Evolution Reaction

AbstractAlthough alloying Pt with Ru has recently been reported as an advanced catalyst for the hydrogen evolution reaction (HER), their electrocatalytic performance and high cost are major limitations of the electrochemical water‐splitting technology. Therefore, the study herein reports a doping strategy of Ni atoms into the RuPt lattice that not only further reduces the noble metal content but also enhances the overall HER efficiency via the formed synergistic effects. With boosting reaction kinetics, the as‐made ternary alloy catalyst exhibits improved HER efficiency, achieving a low overpotential/Tafel slope of 22.14 mV/23.92 mV dec−1 in the 0.5 m H2SO4 and 46.52 mV/37.82 mV dec−1 in the 1.0 m KOH electrolyte. Furthermore, the NiRuPt/Activated XC‐72 shows high TOFs (4.13 H2 s−1 at 50 mV/3.88 H2 s−1 at 100 mV in acidic/alkaline electrolyte) and great long‐term stability. This study suggests that the development of Pt‐based ternary nanoalloys is an attractive strategy for using low‐precious metal‐content catalysts for electrochemical energy‐related technologies.

Exploring the Enhanced Catalytic Activity of Pt Nanoparticles Generated on the Red Phosphorus/Graphitic Carbon Nitride Binary Heterojunctions in the Photo-assisted Hydrolysis of Ammonia Borane.

Ammonia borane (AB) holds great promise for chemical hydrogen storage, but its slow dehydrogenation kinetics under ambient conditions requires a suitable catalyst to facilitate hydrogen production from AB. Here, we fabricated binary red phosphorus/graphitic carbon nitride (RP/g-CN) heterojunctions decorated with Pt nanoparticles (NPs, denoted Pt/RP/g-CN) with a facile ultrasound-assisted two-step protocol as a photo-assisted catalyst for the hydrolysis of AB (HAB). The heterojunction established through intimate P-O-N bonds was proven to have improved photophysical properties such as a lower electron-hole recombination and enhanced visible light utilization compared to the pristine components. With the incorporation of Pt NPs, the optical properties of RP/g-CN heterojunctions were further improved through Schottky junction formation between semiconductors and Pt NPs, enabling a superb hydrogen gas (H2) generation rate of 142 mol H2·mol Pt-1·min-1 under visible light irradiation. Even though g-CN is a well-known host material for many metal NPs, here we discovered that the interaction of Pt NPs with RP in the ternary heterojunction structure is more favorable than that of g-CN, stressing the key role of RP as a support material in the designed ternary heterostructure. The band alignment of the ternary heterojunction catalyst along with the flow of charge carriers was also studied and shown to be a type-II heterojunction structure without hole migration, namely, a complex type-II heterojunction. Several scavenger experiments were also conducted to explain the mechanism of the photo-assisted HAB. To the best of our knowledge, this is the first example of a dual mechanism proposed for the visible light-assisted HAB. While the majority of the H2 was believed to be produced on the Pt NPs surface with the traditional B-N bond dissociation mechanism, the strong oxidizing action of OH• radicals formed by the heterojunction photocatalyst was also speculated to account for the 33% increase in the activity upon visible light irradiation through another mechanism.

Enhanced Industrial Dye Degradation and Antibacterial Activity Supported by the Molecular Docking Study of Yttrium and Carbon Sphere-Doped Lanthanum Oxide Nanostructures.

As the population grows, the scientific community remains focused on researching new materials, methods, and devices to ensure the availability of safe drinking water. The main aim of this research was to decrease the recombination rate of the charge carriers of La2O3 and enhance the catalytic and antimicrobial activity by employing Y/Cs- doped La2O3, respectively. In the current study, different concentrations of yttrium (Y) and a fixed amount of carbon spheres (Cs) doped into lanthanum oxide (La2O3) nanostructures (NSs) were synthesized by the coprecipitation technique. Cs are used as a cocatalyst as they have a high surface area and small size attributed to increased active sites and decreased recombination rate. Moreover, Y was further incorporated as it activates the generation of reactive oxygen species in the inhibition zone, enhancing the antibacterial activity and reducing the emission intensity. Advanced techniques were utilized to determine the structural properties, optical emission and absorption, elemental composition, and d-spacing of the synthesized samples. The reported ternary catalyst works efficiently, improving the catalytic activity and bactericidal potential. Moreover, in silico molecular docking studies, Cs-doped La2O3 and Y/Cs-doped La2O3 nanostructures toward DNA gyrase Escherichia coli showed good efficacy for antibacterial activity.

One-step preparation of novel Bi-Bi2O3/CdWO4 Z-scheme heterojunctions with enhanced performance in photocatalytic NH3 synthesis

This study focuses on the design and synthesis of a novel ternary composite photocatalyst, Bi-Bi2O3/CdWO4, using a one-step solvothermal method. A comprehensive investigation was conducted to analyze the morphology, specific surface area, structure, optical property, and photoelectric chemical property of the composite. The incorporation of Bi-Bi2O3 was found to significantly impact the growth of CdWO4 crystals, resulting in a morphological transformation into nanoparticles. This morphological change has been shown to enhance the specific surface area of the catalyst, thereby improving its catalytic performance. Furthermore, the incorporation of Bi-Bi2O3 has been demonstrated to greatly enhance the light absorption capability of CdWO4, which also favored the photocatalytic N2 fixation (PNF) reaction. However, after conducting a comprehensive analysis of different Bi-BiO3/CdWO4 and two reference samples Bi/CdWO4 and Bi2O3/CdWO4, it was determined that the improvement of photogenerated charge carrier separation efficiency is the decisive factor determining the performance of the ternary composite catalyst. The closely bound Bi-Bi2O3 on the CdWO4 surface triggers the formation of a heterojunction structure at their interface. By analyzing the band structure of CdWO4 and Bi2O3, it is suggested that the heterojunction operates through a Z-scheme mechanism. The Bi metal serves as a bridge that intimately binds CdWO4 and Bi2O3, facilitating the rapid migration of electrons and improved charge separation. Therefore, the Bi-Bi2O3/CdWO4 composite exhibits high performance in PNF reactions. The optimal 7.5% Bi-Bi2O3/CdWO4 catalyst presents a PNF rate of 434.9 μmol L−1 g−1 h−1 under simulated sunlight irradiation, which is 4.9 times that of pure CdWO4. These findings from this study may offer valuable insights into the design and synthesis of new photocatalysts for PNF.

Metallic Glass Nanofoam Anode Catalysts for Anion-Exchange Membrane Water Electrolyzers

Alkaline anion-exchange membrane water electrolyzers (AEMWEs) for hydrogen production are now receiving intensive attention due to their feasibility to use sustainable, low-cost platinum group metal (PGM-free) catalysts. Although a variety of highly efficient PGM-free catalysts for the oxygen evolution reaction (OER) have been explored, few of them demonstrated satisfied performance in real AEMWEs due to the insufficient electrical conductivity and unfavorable interfaces with ionomers in 3D porous electrodes. Herein, we report a series of highly porous ternary NiFeM (M: Cu, Co, and Mn) metallic glassy catalysts featured with nanofoam network morphologies, which are composed of amorphous OER active metal oxide shells and highly electrically conductive metallic glass alloy cores. Due to these unique properties, these NiFeM nanofoam catalysts demonstrated promising OER activities and stabilities in the half-cell with aqueous alkaline electrolytes, especially at high potentials. We also examined their magnetic properties and found no direct correlation with measured OER activity. These ternary NiFeM catalysts are further integrated with unique ionomers and AEMs to fabricate AEMWEs, showing superior performance to binary NiFe and commercial IrO2 catalysts when utilizing diluted KOH electrolytes. A different trend was identified when directly using desirable but challenging pure water, and the NiFeCu catalyst performed the best comparable to IrO2 especially at high current densities. Although deep understanding on limiting factor of pure water AEMWEs is still required, these NiFeM catalysts with favorable catalytic and morphological properties representing a new class of highly efficient PGM-free anode catalysts for viable AEMWEs toward clean hydrogen generation.

Ternary NiMo-Bi liquid alloy catalyst for efficient hydrogen production from methane pyrolysis.

Methane pyrolysis (MP) is a potential technology for CO2-free hydrogen production that generates only solid carbon by-products. However, developing a highly efficient catalyst for stable methane pyrolysis at a moderate temperature has been challenging. We present a new and highly efficient catalyst created by modifying a Ni-Bi liquid alloy with the addition of Mo to produce a ternary NiMo-Bi liquid alloy catalyst (LAC). This catalyst exhibited a considerably low activation energy of 81.2 kilojoules per mole, which enabled MP at temperatures between 450 and 800 Celsius and a hydrogen generation efficiency of 4.05 ml per gram of nickel per minute. At 800 Celsius, the catalyst exhibited 100% H2 selectivity and 120 hours of stability.

Photocatalysis-Fenton mechanism of rGO-enhanced Fe-doped carbon nitride with boosted degradation performance towards rhodamine B

A photo-Fenton catalyst Fe‑carbon nitride (g-C3N4)/reduced graphene oxide (rGO) (labeled as FNGO) was prepared via two-step calcination thermal polymerization. rGO as a carrier of Fe-g-C3N4 accelerated the charge transfer and improved the reduction of Fe (III) as compared those of the binary Fe-g-C3N4 catalyst. The FNGO catalyst maintained a high surface area of 264.7 m2/g and its charge transfer rate was 2.77 times higher than Fe-g-C3N4. The decreasing transient photocurrent and increasing electrode resistance of FNGO, Fe-g-C3N4 and g-C3N4 confirm the positive synergistic effect of FeN coordination and rGO in charge transfer. Under the synergistic of visible light irradiation and H2O2, the excellent degradation performance of FNGO towards rhodamine B was achieved (95.3 % removal) at Fe-doping content of 10 wt%, rGO loading content of 0.5 % and H2O2 addition of 1.5 mM. Hydroxyl radicals played a dominant role in the photocatalysis-Fenton system, which was related to the coordination of FeN, the carrier off-domain of rGO, and the Fe (III)/Fe (II) cycle promoted by photogenerated electron and superoxide radicals. The FNGO had a high stability, a wide pH adaptation (3– 11) and a low Fe-leaching. This novel ternary light-driven photo-Fenton catalyst of FNGO enabled efficient decontamination during advanced treatment of wastewater.

Critical roles of Co‐doped g‐C3N4/Bi2WO6 in photocatalytic removal of organic pollutants and treating oil field wastewater in electrocatalysis‐microbial fuel cells

AbstractBACKGROUNDPhotocatalysts with Z‐type heterojunction structures for organic pollutant removal are prospective in environmental advanced oxidation processes. Introducing single metal atom to the heterojunction can further improve the synergistic activity of photocatalysts, so we doped Co single metal atom in g‐C3N4/Bi2WO6 Z‐type heterojunction.RESULTSFor this aim, a simple calcination and hydrothermal method was used to dope single atom Co on top of the Z‐type 10 wt% g‐C3N4/Bi2WO6 heterojunctions which we had tested previously. The optimal Co doping was determined at 0.2 wt% Co/10 wt% g‐C3N4‐Bi2WO6, that it most efficiently degraded (100 mg/L) RhB under visible light irradiation (99.7% in 30 min, kinetic rate constant 0.182 min −1). This single‐atom doped catalysts (Co/g‐C3N4/Bi2WO6) should be most favorably used in treating practical wastewater in EC (electro‐chemical)‐MFC (microbial fuel cell) system. Its remarkable performance was recorded (96% COD removal and 92.8% TOC removal).CONCLUSIONThe reactive oxidizing species include h+, 1O2, ·O2−, e−, and OH, they act together leading to the rapid degradation of pollutants. The developed Co‐doped ternary catalyst has promising application prospects in pollution control in real world wastewater treatment. © 2023 Society of Chemical Industry.

A ternary composite catalyst α-DMACoPc/UiO-66-NH2/TiO2 for synergistic photocatalytic degradation of dyes

A ternary composite α-DMACoPc/UiO-66-NH2/TiO2 was synthesized by solvothermal method and characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and other means. The composite catalyst was applied to decompose methylene blue dye in visible light, and the degradation rate reached 93.4%. Compared with the monomer, the composite significantly enhanced the efficiency of the catalytic degradation due to the synergistic effect between composites. The transport speed of charge is accelerated and the recombination of hole-electron pairs is inhibited due to the larger specific surface area. A feasible scheme was provided for preparation of composite catalyst and photocatalytic degradation of dye.

A principal component analysis assisted machine learning modeling and validation of methanol formation over Cu-based catalysts in direct CO2 hydrogenation

With the advent of powerful machine learning algorithms strongly supporting complex non-linear regression modeling, catalyst design features for a wide and customized set of catalysts used for a specific reaction have been made easy. Herein, we use these techniques in the methanol synthesis by CO2 reduction over Cu-based binary and ternary catalysts with the help of three machine learning algorithms: artificial neural network, support vector machine regression, and gaussian process regression. 227 catalytic performance dataset points from existing literature on CO2 hydrogenation to methanol were compiled and initially accessed by Principal Component Analysis (PCA) for training and preliminary evaluation of the algorithms, which was further guided using a 10-fold cross-validation method. The predictive model and its insights were validated experimentally over 30 datasets derived from experimental runs of this reaction over a ternary Cu/ZnO/ZrO2 laboratory-synthesized catalyst at varying conditions of temperature, pressure, and space velocity in a continuous mode fixed-bed plug-flow reactor. The assessment of the space of input and laboratory data was aided by Principal Component Analysis (PCA), scores, and loadings plot. This work shows how experimentalists can predict typical heterogeneous catalytic reaction outputs (R2 greater than 0.9 for three variables) with fair accuracy using a combination of machine learning and PCA.

The intriguing bifunctional effect of strong metal support interaction (SMSI) and hydrogen spillover effect (HSPE) for effective hydrogen evolution reaction

The mechanistic insights behind the kinetics of Hydrogen evolution reaction are unraveled through the bifunctional effect - Strong Metal Support Interaction (SMSI) and Hydrogen Spillover Effect (HSPE) on the WO3 hexagonal nanorods decorated with gold clusters and supported on the reduced graphene layers. The investigation is extended to scaling the electrocatalyst in a flexible electrode-carbon fiber for robust hydrogen evolution reaction in broad pH spectra. The research found that the proposed electrocatalyst demonstrated a reduced overpotential of 20 mV at a current density of 10 mA cm2 in acidic conditions and the stability of the ternary catalyst was verified through the Pourbaix profile. The Tafel slope was also comparable to that of the noble metal electrocatalyst Pt/C, with values of 35 mV dec–1 in 0.5 M H2SO4. The study demonstrated the potential for large-scale application of the proposed catalyst with stable operation observed for 24 h.

Revealing the effect of electronic interaction between dual redox sites on CeO2-Fe2O3 NH3-SCR catalyst through interface contact tailoring

Due to the requirements of different applications environments, higher catalytic activity or SO2 and H2O tolerance, the binary or ternary metal oxide NH3-SCR catalysts with dual redox sites have been widely studied in recent years. The electronic interaction between the dual redox sites has a significant impact on the catalyst performance. Herein, a series of CeO2-Fe2O3 composite catalysts with continuously enhanced interface contact as well as electronic interactions were prepared through a facile grinding method. The activity tests showed that neither the catalyst with the least interfacial contacts nor the one with the greatest interfacial contacts exhibited the highest NOx removal activity. The comprehensive characterizations demonstrated that the apparent physicochemical properties including the NH3 adsorption ability, redox property, and so on, changed in favor of NH3-SCR reaction when enhancing the interface contact for the CeO2-Fe2O3 composite catalysts. However, the reaction mechanism as well as the reactivity of main NH3 and NO adsorbed species were also altered by the electronic interactions between Ce and Fe active species. The unsatisfactory NOx removal activity of the CeO2-Fe2O3 catalyst with strongest electronic interactions between Ce and Fe active species was explained by the reactivity of main NH3 and NO adsorbed species. This work can provide new ideas for improving the performance of NH3-SCR catalysts through changing the interface contact and electronic interaction between the dual redox sites.

Visible light-assisted efficient degradation of Rhodamine B by N-TiO2/Mn-HPMo/Ag ternary composites

In this paper, Ag nanoparticles were deposited on the surface of nitrogen-doped titanium dioxide coupled with manganese-substituted phosphomolybdic acid composites (N-TiO2/Mn-HPMo) using photoreduction method to construct ternary photocatalysis-Fenton composite catalyst (N-TiO2/Mn-HPMo/Ag), and the degradation performance of the catalyst was evaluated with Rhodamine B (RhB) as the target pollutant. The results showed that the N-TiO2/Mn-HPMo/Ag ternary composite catalyst had remarkable visible light activity, and the degradation efficiency of RhB could reach 96.3% in 20 min under visible light. Meanwhile, UV–vis diffuse reflectance spectroscopy illustrated the promotion effect of Ag deposition on the visible light response of N-TiO2/Mn-HPMo. The behavior of photogenerated charges was also characterized by Surface Photovoltage Technique, which further demonstrated that Ag deposition not only extended the light absorption range but also enhanced the separation efficiency of photogenerated charges. This work provides favorable information for the construction of efficient catalysts with high activity under visible light.

Synthesis of highly efficient Cu-PtRu ternary metal catalyst for methanol oxidation

Development of remarkably catalytic activity and CO resistance catalyst has become a focus for methanol oxidation. In this study, the irregular polyhedral of Cu was synthesized by simple electrochemical deposition method. Then Pt-Ru alloy nanoclusters were uniformly deposition on Cu polyhedra to prepare Cu-PtRu ternary alloy materials. The morphology and structure of the ternary alloy were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). Electrochemical results showed that Cu-PtRu exhibited favorable catalytic capacity and high CO resistance for methanol oxidation. In various proportion of Pt-Ru, Cu-Pt5.2Ru1 showed the highest electrocatalytic activity (638.2 mA mgPt−1) for methanol oxidation, which was 2.2 and 2.84 folds relative to commercial Pt/C (Pt wt.20%) and PtRu/C (Pt wt.30%), respectively. Therefore, Cu-Pt5.2Ru1 might be used as a novel structure electro-catalyst for methanol oxidation.

Regulating catalytic stability of PtSnM/CeO2 (M = Mn, W, Nb) catalysts via the closely coupled multi-active sites to promote multicomponent VOCs oxidation

Pt-based commercial catalysts tend to be poisoned by chlorine species in the oxidation of chlorinated volatile organic compounds (CVOCs), which greatly limits their wide applications. It is vital to develop the active catalysts with good chlorine resistance. In the present work, the novel supported ternary metallic catalysts (PtSnM/CeO2; M = Mn, W, Nb) with the closely coupled multi-active sites show good catalytic performance and excellent chlorine resistance for the oxidation of toluene and chlorobenzene (CB), and can effectively inhibit formation of the toxic chlorine-containing by-products. The catalytic activity for toluene oxidation in the mixed VOCs system follows the sequence: PtSnMn/CeO2 > PtSnW/CeO2 ≈ PtSnNb/CeO2 > PtSn/CeO2 > Pt/CeO2. The change of the electron structure around Pt results in the difference in adsorption capacity of toluene and CB. The C−Cl bond is first dissociated at the Brønsted acid sites, and the non-chlorinated organic compounds are oxidized at the Pt sites that contact with the acid sites in the proximity. Additional water provides sufficient protons to react with Cl species, enhancing the desorption amount of HCl; furthermore, the water also reacts with the adsorbed oxygen to generate new oxygen species, which participates in the oxidation of VOCs, so as to accelerate the removal of Cl species on the catalyst surface and reduce the more toxic polychlorine by-products. This work is helpful for developing the supported noble metal catalysts with good chlorine-resistant performance in the oxidation of multicomponent VOCs under the actual industrial conditions.

Solar-driven photodegradation of synthetic dyes by ternary of titanium oxide-copper oxide-chitosan catalyst

The ternary titanium oxide (TiO2), copper oxide (CuO), and chitosan (TiO2/CuO/Chitosan) photocatalyst (composites) for the photodegradation of synthetic methyl orange (MO) were developed by entrapping copper ions and nanosized TiO2 into chitosan thin films at room temperature. TiO2 Degussa P25 was incorporated with CuO and Chitosan (CS) solution using an ex-situ synthesis method before being immobilized onto glass plates via a dip-coating technique. This study is the first time approach for a combination of a composite comprising two metal oxides to suppress the electron-hole recombination, thus enhancing their catalytic and adsorptive properties. The morphology and surface interactions of the TiO2/CuO/Chitosan composite were determined using techniques such as XRD, FTIR, RAMAN, and SEM-EDX, respectively. The results show the anatase phase and homogenous spherical features of TiO2. The TiO2/CuO/Chitosan composites (0.5 gL-1) exhibited excellent activity for the photodegradation of MO under solar irradiation (λ > 400 nm) at different pH. The decolorization efficiency increased according to pH 9 < pH 7 < pH 6 < pH 3 with the highest degradation efficiency of 85.29% at 1 ppm MO solution, reaching two times greater than the pristine TiO2 nanoparticles (56.55%). Complete degradation of MO was attained at 240 min of solar irradiation with pH 3 using the optimum TiO2/CuO/Chitosan composites of 1:4:1 composition (5 cycles of dip coating) and the photodegradation rate constant is 0.0073 min−1. The physic-chemical study has established the structure, crystalline phase, surface contact, and stability of the catalyst. The photocatalytic improvement under visible irradiation is attributed to band-gap reduction and suspension of electron-hole recombination of the ternary catalyst system. The results of this study offer guidelines for the design of a new synthetic strategy.for the preparation of an efficient photocatalyst for the selective oxidation of synthetic azo dyes compounds.

Heterojunction Mo-based binary and ternary nitride catalysts with Pt-like activity for the hydrogen evolution reaction

The development of earth-abundant electrocatalysts with Pt-like catalytic activity for the hydrogen evolution reaction (HER) is of great significance to green hydrogen production. Herein, a novel strategy is described to construct dual-phase nitride nanobelts composed of Mo2N and Ni0.2Mo0.8N by nitridation of Ni2+ intercalated layered MoO3 nanobelts (NBs). The Mo2N/Ni0.2Mo0.8N catalyst exhibits superior stability and a low overpotential of 26 mV at 10 mA cm−2 and Tafel slope of 31 mV dec−1 in both the alkaline electrolyte and simulated seawater, which is comparable to or better than that of the benchmark Pt/C catalyst. The excellent alkaline HER characteristics is attributed to the Mo2N/Ni0.2Mo0.8N heterostructure with adjustable content and robust interfaces and without metal Ni segregation and structure collapse during nitridation. Density-functional theory (DFT) calculations and experiments reveal that the Mo2N/Ni0.2Mo0.8N interface with strong electronic interactions optimizes H adsorption/desorption yielding moderately weak bonding metal sites with positive ΔGH* as the catalytic centers, thereby accelerating the HER kinetics and boosting the HER activity. The results reveal a simple strategy for the preparation of heterostructured nitride-based catalysts with Pt-like activity for hydrogen evolution.

Plasmonic Au Nanoparticle of a Au/TiO2-C3N4 Heterojunction Boosts up Photooxidation of Benzyl Alcohol Using LED Light.

Plasmonic Au nanoparticles (NPs) employing localized surface plasmon resonance excitation have exhibited superior visible light absorption for many organic transformations. In this work, we prepared a ternary composite catalyst comprising plasmonic Au NPs and a 2D/2D TiO2-C3N4 heterojunction via a photoreduction method of chloroauric acid in the presence of TiO2-C3N4. The introduction of plasmonic nanogold particles embedded onto the TiO2 surface of the TiO2-C3N4 heterojunction can significantly improve the photocatalytic performance during photooxidation of benzyl alcohol to benzaldehyde under mild conditions (1 bar air, white LED irradiation at ambient temperature). The productivity over Au/TiO2-C3N4 (0.25 mmolreactedBA gcat.-1 h-1) is found to be ∼5.6, 8.3, and 8.2-fold of these over the Au/TiO2, TiO2-C3N4, and C3N4-Au-TiO2 heterojunctions, respectively. Trapping experiments and electron spin resonance (ESR) spectroscopy confirm that the superoxide (·O2-) and hydroxyl radicals (·OH) act as the reactive oxygen species during photooxidation. Furthermore, the experimental results combined with density functional theory calculations reveal that the chemisorbed benzyl alcohol population, surface oxygen vacancies, and lifetime of photoexcited electrons and holes are largely improved by plasmonic Au NPs. This study on nanogold composites provides some hints for developing new efficient and practical photocatalysts.

Eg Orbital Occupancy-Dependent Intrinsic Catalytic Activity of Zn–Co–Mn Spinel Oxides in Fenton-like Reactions

Transition-metal (TM)-based spinel oxides have demonstrated excellent efficacy in Fenton-like reactions, but the key mechanism behind peroxymonosulfate (PMS) adsorption, decomposition, and pollutant degradation is still unclear. Here, a crucial role of eg orbital occupancy in manipulating the interaction between PMS and Zn–Co–Mn ternary spinel catalysts and the resulting pollutant degradation is first discovered. The introduction of Co into the ZnMn2O4 network lowers the magnetic momentum and eg occupancy and favors the overlap between TM eg and O 2p orbitals. Experimental results demonstrate that the eg occupancy-dependent catalytic activity and pathway originate from its cascade effect on PMS binding, decomposition, and radical desorption. Zn–Co–Mn with optimized eg occupancy exhibits favorable PMS binding strength, interaction capability, radical desorption, and pollutant degradation. Cyclic voltammetry (CV) and density functional theory (DFT) corroborate the critical role of eg in PMS affinity. In addition, the ZnCoMnO4/PMS system shows high selectivity for carbamazepine (CBZ, 0.275 min–1) and environmental robustness. The surface active complex PMS*, the peroxymonosulfate radical, and the sulfate radical are identified as reactive species. This work provides an intrinsic mechanism behind pollutant degradation and offers guidance for performance enhancement in a water environment.