Catalytic Reaction Research Articles

Structural and biochemical insights into the molecular mechanism of N-acetylglucosamine/N-Acetylmuramic acid kinase MurK from Clostridium acetobutylicum

MurK is a MurNAc- and GlcNAc-specific amino sugar kinase, phosphorylates MurNAc and GlcNAc at the 6-hydroxyl group in an ATP-dependent manner, and contributes to the recovery of both amino sugars during the cell wall turnover in Clostridium acetobutylicum. Herein, we determined the crystal structures of MurK in complex with MurNAc, GlcNAc, and glucose, respectively. MurK represents the V-shaped fold, which is divided into a small N-terminal domain and a large C-terminal domain. The catalytic pocket is located within the deep cavity between the two domains of the MurK monomer. We mapped the significant enzyme-substrate interactions, identified key residues involved in the catalytic activity of MurK, and found that residues Asp77 and Arg78 from the β4-α2-loop confer structural flexibilities to specifically accommodate GlcNAc and MurNAc, respectively. Moreover, structural comparison revealed that MurK adopts closed-active conformation induced by the N-acetyl moiety from GlcNAc/MurNAc, rather than closed-inactive conformation induced by glucose, to carry out its catalytic reaction. Taken together, our study provides structural and functional insights into the molecular mechanism of MurK for the phosphorylation of both MurNAc and GlcNAc, sugar substrate specificity, and conformational changes upon sugar substrate binding.

Enhancement of oxygen flux through Nb-doped La0.4Sr0.6FeO3-δ ceramic hollow fiber membranes by Fe exsolution

In recent years, numerous studies have focused on the use of mixed ionic-electronic conducting oxides for coupled oxygen separation and catalytic reactions in membrane reactors. A promising strategy for the efficient fabrication of oxygen separation membranes involves modification of the membrane surface via exsolved metal nanoparticles decoration. Here, we present a detailed characterization of the structural and transport properties of a novel membrane material La0.4Sr0.6Fe0.95Nb0.05O3−δ (LSFNb5). The exsolution of Fe nanoparticles was observed after heating of LSFNb5 in a reducing atmosphere (5 % Н2/Ar) and was confirmed by X-ray diffraction analysis, Mössbauer spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The formation of Fe nanoparticles on the surface of LSFNb5 hollow fiber membrane in the reduction process leads to the enhancement of oxygen fluxes and reduces the apparent activation energy. Kinetic parameters for oxygen transport through LSFNb5 hollow fiber membrane estimated using two different models, are in good agreement with the experimental results. Furthermore, LSFNb5 hollow fiber membrane demonstrates stable performance both before and after surface treatment.

Chemical recycling of polyethylene terephthalate using a micro-sized MgO-incorporated SiO2 catalyst to produce highly pure bis(2-hydroxyethyl) terephthalate in high yield

Chemical recycling is a feasible method for achieving the closed-loop recycling of polyethylene terephthalate (PET). In this strategy, post-consumer PET is depolymerized to bis(2-hydroxyethyl) terephthalate (BHET) via glycolysis, which is then repolymerized to yield recycled PET (rPET). Herein, we introduce an innovative approach for the chemical recycling of PET that focuses on glycolysis facilitated by a microsized MgO-incorporated SiO2 catalyst. This choice of catalyst is groundbreaking owing its superior glycolysis-catalysis efficiency and the ease with which it can be separated from the reaction mixture, thereby addressing the common challenges faced by traditional catalysts during PET depolymerization. By employing a heterogeneous catalyst with significantly larger particles than a conventional catalyst, we not only aimed to simplify the catalyst-removal process, thereby improving BHET purity, but also observed enhanced efficiency during the catalytic reaction that led to a superior yield of the desired product. The catalyst was synthesized using a wet impregnation method and its efficiency was evaluated at various reaction times and dosages, which revealed that the microsized MgO/SiO2 catalyst significantly outperforms traditional catalysts, to deliver a 95.1% yield of BHET with negligible amounts of metal detected in the final product. This study not only demonstrated the potential of microsized catalysts during PET glycolysis, but also contributes to the advancement of sustainable PET-recycling practices. We anticipate that the microsized MgO/SiO2 catalyst is a promising alternative for the industrial upcycling of PET waste.

Adsorbate-induced adatom formation on Au-Cu bimetallic alloys and its possible consequences for CO2 electroreduction

The adsorbate-induced formation of sub-nanometer clusters on transition-metal single crystals observed in previous high-pressure microscopic studies hinted at the in-situ formation of unique active sites even on large nanoparticle catalysts. We propose that the adatom formation energy can be used as an energetic descriptor for the initial step toward the adsorbate-induced metal-cluster formation process. This descriptor can be efficiently computed using density functional theory (DFT) calculations and applied for screening and identification of metal catalysts where this phenomenon may play an important role in generating active sites in-situ. As a proof of concept, here, we construct an adatom formation energy database for three AuxCuy alloys (x:y = 3:1, 1:1, or 1:3) and eighteen adsorbates (H, C, N, O, F, S, Cl, Br, I, CHx, NHx (x = 1 – 3), CO, NO, and OH) commonly involved in catalytic reactions. The energetics of adatom formation were examined in all cases where the (111) terrace, (211) step-edge, and (874) kink were the sources of the adatom. We demonstrate that the presence of an adsorbate could alter not only the energetics for adatom formation but also the elemental nature of the preferred adatom being formed. Using our database, we identified promising systems which favor adsorbate-induced adatom formation under near-ambient conditions. Specifically, CO-induced adatom formation on all three Au-Cu alloy surfaces could occur under CO2 electroreduction (CO2RR) conditions. This phenomenon offers a qualitative explanation for the experimentally observed CO2RR activity on Au-Cu alloy catalysts. Our methodology offers an easily expandable and efficient approach for large-scale catalyst screening with regards to adatom/cluster formation under reaction conditions and provides insight into the possible nature of active sites on alloy catalysts from a novel perspective.

Pyroelectric field drived photocatalysis by ZnFe2O4/NaNbO3 heterojunction for dye degradation through integration of solar and thermal energy

A novel composite of ZnFe2O4/NaNbO3 (ZFO/NNO) nanorods with a p-n heterojunction structure was successfully synthesized via the hydrothermal method. The NNO nanorods were heated in situ using the photothermal effect of ZFO and subsequently cooled to room temperature, creating a cyclic heating and cooling process for ZFO/NNO. The catalytic activity of the resulting nanorods was assessed through the degradation of Rhodamine B, reaching 98% degradation efficiency after 180 min, attributed to the synergistic effect of pyrocatalysis and photocatalysis. Compared with NNO and ZFO individually, the enhanced performance of ZFO/NNO can be attributed to several synergistic factors, including the expanded spectral range of light absorption for ZFO, the establishment of the built-in electric field of the p-n junction between ZFO and NNO, and the NNO pyroelectric effect that further improved the charge transfer efficiency. Superoxide radicals and holes generated from photo-induced electrons were identified as the active species. Hydroxyl radicals generated from pyroelectrically-induced charge also participated in catalytic reaction. The combined effect of pyroelectric and photocatalytic processes could significantly improve the coupled pyro-photocatalytic reaction for pyroelectric semiconductor heterostructure, enabling the utilization of multiple energy sources, including solar and thermal energy.

Development of Air–Ti Gas-Surface Reaction Mechanisms and Rate Calculations

Gas-surface reaction mechanisms and rates were developed for an air–titanium surface to support finite-rate catalytic surface reaction models used in computational fluid dynamics. For the surface dissociation/recombination reactions, a two-step reaction method was applied based on the assumption that two atoms must be positioned in adjacent cells to recombine. Transition state theory was used to calculate the surface reactions for adsorbed diatomic molecules to dissociate to the adjacent unit cell or atoms located in the adjacent cells to recombine into diatomic molecules. For the second step, atoms located in the adjacent cells are allowed to further dissociate to another cell (total separation), or totally separated atoms recombine into the adjacent cells. A stochastic gas-surface kinetics simulation code, STOKIN, was developed to simulate gas-surface reactions and to calculate the equilibrium constants of second molecular dissociation ⇌ recombination processes. Thermodynamic properties of the adsorbates (enthalpies, entropies, and heat capacities) were calculated using density functional theory along with statistical mechanics assuming no rotational and translational contributions to the entropies and heat capacities due to the adsorbates’ inability to freely move or rotate on the surface.

Enhancing photocatalytic degradation of La-BiVO4 through bidirectional regulation of oxygen vacancy and the Mott-Schottky effect

Selective oxidation of photocatalysts is an important reaction, but catalytic capacity and reaction selectivity are usually contradictory. Herein, ultrafine La nanoparticles were introduced to regulate and control the coordination number and environment of Bi, and a catalyst was synthesized with oxygen defects (La-BiVO4) for Rhodamine degradation. Particularly, La-BiVO4 achieved a better reaction rate and selectivity under visible-light irradiation. The results revealed that the degradation rate of Rhodamine by La-BiVO4 reached 94.9 %. Additionally, the characterization and density functional theoretical calculation demonstrated that the Mott-Schottky effect in La-BiVO4 not only changed the BiVO4 electron density and boosted the visible-light-sensitivity, but also hastened the photogenerated charge migration and reduced the energy barrier. This study not only reveals the important role of optimizing single-atom coordination environment in generating free radicals in photocatalytic reactions, but also provides a reasonable degradation strategy for specific pollutants in the environment.

Designing ternary Co-Ni-Fe layered double hydroxides within a novel 3D cross-flower framework for efficient catalytic performance in oxygen evolution reaction

In this study, we synthesized novel three-dimensional (3D) cross-flowered Co-Ni metal–organic framework (Co-Ni-MOF) precursors using the chemical precipitation method. Subsequently, we obtained Co-Ni-Fe layered double hydroxides (Co-Ni-Fe-LDHs) through an ion exchange strategy, which preserved their original morphology while consisting of ultrathin layered hydroxide nanosheets. The interlayer spacing of the LDH lamellar structure was finely tuned by varying the ratios of Co to Ni. The results demonstrated that Co-Ni-Fe LDHs, characterized by a unique three-dimensional cross-shaped structure and an optimal composition ratio of Co2+:Ni2+ = 2:1, exhibited increased interlayer spacing. This structural characteristic contributed to their excellent electrochemical performance, positioning them as optimal electrode materials for catalytic oxygen evolution reactions (OER). Our observations revealed that Co-Ni-Fe-LDHs exhibited remarkable OER activity, characterized by a low Tafel slope of 41.82 mV dec−1, a low overpotential of 322 mV at a current density of 10 mA cm−2, and outstanding stability over a 48-hour period. In-situ Raman spectroscopy results indicated that the active site of the composite was γ-CoOOH. Additionally, the room temperature stirring and standing strategy employed in this study is easier to scale up and yields a higher quantity of reaction products compared to traditional high-temperature and high-pressure conditions. This investigation provides novel insights into the design and fabrication of Co-Ni-Fe-LDHs catalyst with 3D cross-flower structures, demonstrating enhanced electrocatalytic activity and commendable stability. These findings suggest promising applications in the field of electrolyzed water.

Persistent ultraviolet luminescence and photocatalytic properties of SiO2-Zn2SiO4:Ga,Pb nanoparticles

Persistent phosphors possess unique afterglow optical properties. In this paper, a class of ultra-violet (UV) persistent luminescence nanoparticles were developed for catalytic photodegradation applications. UV persistent luminescence nanoparticles of SiO2-Zn2SiO4:Ga and SiO2-Zn2SiO4:Ga,Pb were successfully synthesized by using a mesoporous template method. The UV persistent luminescence intensity of SiO2-Zn2SiO4:Ga at 405 nm was enhanced up to ca. 3.5 times by co-doping with Pb2+ (396 nm), along with longer persistent luminescence duration. The photodegradation results indicate that it is useful to introduce UV persistent luminescence property into SiO2-Zn2SiO4:Ga,Pb to obtain enhanced catalytic activity of SiO2-Zn2SiO4 with a bigger catalytic oxidation reaction kinetic constant (up to ∼4 times). This kind of UV persistent catalysis strategy may become a potential feasible method for better catalytic photodegradation activity. The UV persistent photocatalyst has potential applications in the photooxidation of organic molecules in high chroma and/or turbidity aqueous systems.

Catalytic Performance of Chiral Tetraaza-Bridged Calix[4]arene[2]triazine Derivatives for Enantioselective Michael Reactions.

Novel chiral tetraaza-bridged calix[4]arene[2]triazine-based organocatalysts were synthesized and used for catalytic asymmetric Michael reaction of acetylacetone to various aromatic nitrostyrenes. Chiral subunits (R)- and (S)-1,2,3,4-tetrahydro-1-naphthylamine were attached to the tetraaza-bridged calix[4]arene[2]triazine platform in both enantiomeric forms. The R configuration of the major enantiomer of the Michael product was obtained when 3a was used as catalyst, and the S configuration was obtained when 3b was used as catalyst. This indicated that the configuration of the Michael product was controlled by the chiral calixarene moiety. The Michael adducts were obtained in excellent yields (91%) and enantioselectivities (98%).

Advanced catalytic and biomedical applications of silver functionalized SnCuO3 nanocomposites synthesized through novel surfactant mediated chemical approach

In the current contribution, silver impregnated and un impregnated bimetallic oxide nanocomposites of SnCuO3 were synthesized by a novel surfactant mediated chemical approach. The tween-80 was used as a surfactant to effectively modulate the morphological features of the nanocomposites. The synthesized nanocomposites were characterized by XRD, HRTEM, SEM, EDX, FTIR and XPS. The results revealed the rod-shaped surface morphology of the nanocomposites with length and diameter of 245 nm and 66 nm respectively. The synthesized nanocomposites were tested for catalytic and biomedical applications. The rate of catalytic degradation reaction of methylene blue by the SnCuO3 and Ag/SnCuO3 nanocomposites were found to be 10.2 and 8.5 respectively. Only in 10 min all the dye molecules were degraded. The synthesized nanomaterials SnCuO3 and Ag/SnCuO3 are potent antileishmanial agents having CC50 value 12728.03 and 3001.70 µg/mL respectively that were found to be biocompatible with very low toxicity as revealed by their hemolytic activity results. Moreover, the nanostructures exhibited promising antibacterial properties by effectively inhibiting the growth of both E. coli and S. aureus bacteria through photoinhibition. When subjected to visible light irradiation, the growth inhibition zone of Ag/SnCuO3 against E. coli and S. aureus was measured at (15 ± 0.4 mm) and (17 ± 0.3 mm), respectively. These nanostructures demonstrated the ability to impede bacterial proliferation and viability, underscoring their potential for use in water disinfection and as antibacterial coatings utilizing Ag/SnCuO3.

Understanding oxidation potential and degradation mechanism of acid-treated TiO2 coupled g-C3N4 S-scheme heterojunction photocatalyst for the removal of gaseous formaldehyde

In this work, a step (S)-scheme heterojunction catalyst is synthesized by coupling acid-treated TiO2 (ATT) with graphitic carbon nitride nanosheet (g-C3N4: GCN) and used for photocatalytic mineralization of gaseous formaldehyde (FA). The ATT-GCN exhibits superior photodegradation performance against FA (e.g., removal efficiency of 86 %, the reaction rate of 70.2 nmole mg−1 min−1, the quantum yield of 5.1E-02 molec. photon-1, space–time yield of 5.1E-03 molec. photon-1 mg−1, clean air delivery rate of 5.2 L h−1, and specific clean air delivery rate of 515.4 L g-1 h−1) under optimum conditions (e.g., catalyst mass of 10 mg, 20 % relative humidity, and 21 % O2). The acid treatment of TiO2 proves to be an effective approach for improving the surface porosity of ATT with more abundant active sites for efficient catalytic reactions. Similarly, the S-scheme heterojunction displays superior redox potential (i.e., availability of free e- at conduction band of GCN with a reduction potential of −0.485 eV/NHE and free h+ at valance band of ATT with oxidation potential 2.79 eV/NHE). As such, the improved textural and optical properties of ATT-GCN offer outstanding adsorption and photocatalytic oxidation potential against FA molecules. In-situ Kelvin probe microscope analysis of ATT-GCN postulates the formation of a strong built-in electric field to improve the separation of charge carriers. Considerations on the degradation pathway and intermediate dynamics with the aid of in-situ DRIFTS analysis suggest that the oxidation and mineralization of FA molecules should proceed favorably under slightly wet conditions (e.g., 20 % relative humidity). The overall outcomes of this work are expected to help deliver new paths for the construction of advanced photocatalytic systems for upscaled applications in air quality management.

Z-scheme ZnIn2S4/CuxO heterostructure on flexible substrate for efficient photothermal catalytic CO2 reduction

The ZnIn2S4 nanosheets were successfully synthesized on the surface of compacted stainless steel mesh using a simple solvothermal method, and further modified with CuxO nanoparticles to form ZnIn2S4/CuxO heterojunction photocatalyst via a wet chemistry approach. These photocatalysts were then utilized for photothermal catalytic CO2 reduction under full spectrum solar light. The experimental results demonstrated that the deposition of the photocatalyst on the flexible substrate effectively prevented the aggregation of ZnIn2S4 nanosheets. The incorporation of CuxO nanoparticles enhanced the specific surface area of the photocatalyst, and created a Z-scheme heterojunction with ZnIn2S4 to improve the utilization efficiency of photogenerated electrons. It was noteworthy that the dark red CuxO exhibited a full spectrum response and excellent photothermal effect, thereby facilitating carrier migration and reducing CO2 catalytic reaction barriers. Consequently, the optimized ZnIn2S4/CuxO exhibited significantly enhanced CO2 to CO yield of 1515.8 μmol m-2h−1 and CH4 yield of 1579.4 μmol m-2h−1, which was about 7.5 and 7.6 times higher than those achieved by pure ZnIn2S4, respectively. Furthermore, this study provided detailed insights into the mechanism of photocatalytic CO2 reduction over composite material as well as valuable guidance for designing immobilized photocatalysts with high activity for CO2 reduction.

Atomic‐level synergistic catalysts: single‐atom site integrated with atom, cluster and nanoparticle

The emerging atomic‐level synergistic catalysts based on the single‐atom sites and other valuable components, such as atom, cluster, nanoparticle and other nano‐matter, shine in various catalytic fields. They can integrate the advantages of individual catalytic sites and other valuable components to enhance the activity, selectivity and stability of many chemical reactions via activating their key rate‐determining steps and multistep transformations. In addition, because of the ultrahigh atom utilization (~100%) and adjustable microenvironment of metal centers, the single‐atom sites can intelligently construct with other useful large size sites to strengthening in tandem a typical catalytic process. Herein, the structure and mechanism of atomic‐level synergistic catalysts with controllable electronic structures and regulatory reaction processes are presented. We particularly emphasize the interactions between active components of atomic‐level synergistic catalysts and catalytic reaction processes, which are essential for understanding how these catalysts are cooperatively working. It is anticipated that this minireview can make the promotion of advanced atomic‐level synergistic catalysts based on single‐atom sites.

Fluoropyridine modulated local charge distribution of carbon nitride to facilitate photocatalytic oxidative γ-valerolactone production

Synthesis of γ-valerolactone (GVL) from renewable biomass resources under mild reaction condition with metal-free catalysis is attractive but challenging. Herein, a novel porous fluoropyridine-incorporated carbon nitride (FPCN) was constructed and applied for photocatalytic oxidation of biomass-based 5-methyltetrahydrofurfural alcohol (5-MTHFA) to GVL. The catalyst exhibits excellent photocatalytic activity (93% 5-MTHFA conversion), with an 81% GVL yield, which is significantly higher than that of pyridine-incorporated carbon nitride and pure g-C3N4. Catalyst characterization and density functional theory (DFT) calculations showed that the porous structure of FPCN provides more exposed active sites for catalytic reaction, and the incorporated fluoropyridine rings effectively modulate the localization of electron cloud density, resulting in an enhanced photogenarated carrier separation efficiency and adsorption capacity for 5-MTHFA. Mechanistic studies reveal that photocatalytic oxidation process of 5-MTHFA mainly involves hydroxyl group oxidation and decarboxylation. This work provides new insight into designing carbon nitride-based photocatalysts for the efficient selective oxidation of renewable biomass to produce fine chemicals.

Dual electric field effects boost bifunctional oxygen electrocatalysis

Regulation of the surface microenvironment is crucial for the development of highly active and durable OER/ORR bifunctional catalysts. In this study, a bifunctional m-CoSx@NSC electrocatalyst with dual electric field effects was designed and fabricated by synchronous pyrolysis of organic sulfur-rich cobalt compounds (Co-DC) and melem. The introduction of nitrogen-rich melem effectively induced the conversion of Co-DC and the growth of tentacles to form a hierarchical carbon skeleton. The interfacial micro-electric field between the carbon layer and CoSx active species improves the intrinsic activity and stability of m-CoSx@NSC. Finite element method simulation and in-situ measurements proved that the tentacle-induced external local electric field promotes the formation of Co(OH)2/CoOOH intermediates and mass transfer, thus accelerating the catalytic reaction kinetics. Through the synergistic effect of dual electric fields, the m-CoSx@NSC catalyst demonstrated a low overpotential of 340 mV for OER and a high half-wave potential of 0.85 V for ORR. Furthermore, the m-CoSx@NSC-based ZAB exhibited an open-circuit voltage of 1.42 V, a maximum power density of 87.38 mW cm−2, a specific capacity of 876.17 mAh gZn−1, and a cycling performance of 700 cycles. The synergistic regulation of the internal and external microenvironments provides a novel insight to improve the catalytic reaction kinetics of OER/ORR.

From lignin-derived monomers to 1,4-cyclohexanediol via a two steps Dakin oxidation and hydrodeoxygenation reaction

Lignin is the largest renewable source of aromatic building blocks in nature and has great potential as a starting material for the production of bulk or functionalized aromatic compounds, providing a suitable alternative to widely used petroleum-derived chemicals. In this work, we present a novel 1,4-cyclohexanediol (CHDO) preparation from lignocellulose. In contrast to conventional methods, this pathway has taken the lignin-degrading monomers as a starting point, and flexibly employs a series of oxidative and catalytic reactions to achieve the preparation of CHDO. The proposed pathway consists of a two-step chemical process to efficiently obtain high yields of CHDO from lignocellulose. The first step is the oxidation of lignin-derived monophenols to p-hydroxyl phenolic compounds using the Dakin oxidation reaction (yield>80%), and finally the de-functionalization and hydrogenation of the resulting monomers using the hydrodeoxygenation (HDO) reaction.

Green synthesis and characterization of trisubstituted imidazole derivatives by an ecofriendly and efficient heterogenous nanocatalyst based on magnetite nanoparticles coated modified nanocellulose

In the present work, a nanocellulose based magnetic nanocomposite [(Ph-PDA-DANC)@Fe3O4NPs] was synthesized by an ecofriendly and a simple protocol and characterized by means of different techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) equipped with an Energy Dispersive X-ray (EDX) probe and the Value Stream Mapping (VSM). The theoretical study of [(Ph-PDA-DANC)@Fe3O4NPs] was investigated using Density Functional Theory (DFT) at the DFT-D3/ B3LYP/LanL2DZ level of theory to explore the nature of the interactions between the (Ph-PDA-DANC) ligand and magnetite nanoparticles. The results indicate that the Fe3O4 nanoparticles form covalent bonds with the N-ring of the ligand. Then, it was used as a catalyst in the green and efficient procedure for one-pot multicomponent syntheses of imidazole derivatives by the condensation of benzil or 9.10-phenanthrenequinone, benzaldehyde derivatives and ammonium acetate. The catalytic reaction provided the synthesis of above imidazole derivatives with high reaction efficiency (80%-98.1%) in a short reaction time (3h) and in presence of a minimum amount of ethanol. The identification and structure of imidazole derivatives was determined analyzing the 1H NMR (Nuclear Magnetic Resonance) and FTIR spectra. This procedure has several advantages compared to the conventional method such as the high yields, short reaction times, easy separation of the nanocatayst from the reaction mixture by using a magnet, and the reusability of the catalyst.

Optically selective catalyst design with minimized thermal emission for facilitating photothermal catalysis

Converting solar energy into fuels is pursued as an attractive route to reduce dependence on fossil fuel. In this context, photothermal catalysis is a very promising approach through converting photons into heat to drive catalytic reactions. There are mainly three key factors that govern the photothermal catalysis performance: maximized solar absorption, minimized thermal emission and excellent catalytic property of catalyst. However, the previous research has focused on improving solar absorption and catalytic performance of catalyst, largely neglected the optimization of thermal emission. Here, we demonstrate an optically selective catalyst based Ti3C2Tx Janus design, that enables minimized thermal emission, maximized solar absorption and good catalytic activity simultaneously, thereby achieving excellent photothermal catalytic performance. When applied to Sabatier reaction and reverse water-gas shift (RWGS) as demonstrations, we obtain an approximately 300% increase in catalytic yield through reducing the thermal emission of catalyst by ~70% under the same irradiation intensity. It is worth noting that the CO2 methanation yield reaches 3317.2 mmol gRu−1 h−1 at light power of 2 W cm−2, setting a performance record among catalysts without active supports. We expect that this design opens up a new pathway for the development of high-performance photothermal catalysts.

Comparison of thermo-catalytic and photo-assisted thermo-catalytic conversion of glucose to HMF with Cr-MOFs@ZrO2

Abstract Thermo-catalytic and photo-assisted thermo-catalytic are two effective pathways for conversion of glucose. Thermo-catalytic and photo-assisted thermo-catalytic conversion of glucose was studied with Cr-MOFs@ZrO2 as catalysts in nitrogen atmosphere at 150 °C. Cr-MOFs@ZrO2 possesses simultaneously Lewis acid sites as well as Brønsted acid sites, and also has strong Brønsted acidity, so it can exhibit good thermos-catalytic performanc. When the glucose was 3 g/L, the reaction was carried out at 150 °C for 2 h with DMF as solvent, the glucose conversion was 97.9% while the HMF yield was 38%. The yield of HMF can be increased to 51.1% by adding 500w xenon lamp irradiation on the basis of thermal catalytic reaction condition. A comparison of the two reactions revealed that light-assisted thermal catalysis was more favorable for the reaction.