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Cocatalyst loading is of critical importance in efficient photocatalytic water splitting over perovskite oxynitrides. Perovskite CaTaO2N was synthesized for enhancing photocatalytic hydrogen evolution via decoration of a Pt cocatalyst by impregnation–reduction and photodeposition methods. The Pt-loaded CaTaO2N photocatalyst evolves 6.4 μmol H2 per hour, with an apparent quantum yield as high as 0.67% at a wavelength of 420 nm. Decorating the cocatalyst with uniform dispersion and intimate contact onto the surface of narrow-bandgap perovskite oxynitrides is an efficient method to upgrade photocatalytic hydrogen evolution from water splitting. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols to aldehydes/ketones is an important reaction in the fine and bulk chemicals fields. However, the classical alcohol oxidation methods are often performed under unfriendly conditions or use stoichiometric oxidants. Herein, we report an ingenious system that enables high selectivity (up to 99%) and high conversion (up to 97%) with high reaction rates in the aerobic oxidation of alcohols to aldehydes/ketones for a broad range of alcohols, proceeding smoothly via mixing the solvent ethyl acetate and HBr under ambient conditions with visible light irradiation. Experimental characterization and theoretical calculations reveal that solvated dispersion intermediates are formed spontaneously in situ through noncovalent interactions among the molecules in the reaction system, which is proposed to be the origin of the high selectivity and high activity of this reaction. The dispersion system provides a feasible activation approach for aerobic oxidation of alcohols to aldehydes/ketones with high performance under visible light. [ABSTRACT FROM AUTHOR]

Zwitterionic catalysis is powerful in simultaneously activating electrophiles and nucleophiles in organic transformations; however, its potential in polymerizations remains untapped. Herein, a zwitterionic catalytic model for ring-opening polymerization (ROP) is introduced and a series quaternary ammonium carboxylate zwitterionic catalysts have been designed and evaluated in the ROPs of cyclic esters. Among the zwitterionic catalysts, L -carnitine, a commercially available and inexpensive natural product, showed the optimal catalytic performance. ROPs of L -lactide (L -LA), trimethylene carbonate, δ-valerolactone and ε-caprolactone were successful. PLLA was prepared with controlled molecular weight (1.4 to 21.2 kg mol−1) and narrow dispersion (Đ 1.02 to 1.21). The zwitterionic catalytic mechanism is proposed where quaternary ammonium and hydroxyl cooperatively activated the carbonyl of monomers, while the carboxylic anion activated the chain-end/initiator. NMR titrations validated the bifunctional activation mechanism. Organocatalysts of zwitterionic nature provide a new design tool for wider scope investigation of catalytic polymerizations. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) is favored for its photothermal absorption capability in solar vapor generation applications. However, the photothermal conversion efficiency of current PB-based devices is limited by the material's poor dispersion. Herein, we report a method of incorporating PB in the interlayers of layered double hydroxides (LDHs) to prevent its aggregation. The dispersion is further enhanced and stabilized by the addition of sodium dodecyl sulfate (SDS). The thermal and water stability of PB is improved due to the rigid structure of LDHs and interactions between layers and anions. Elemental analysis confirms that with the increase of molar ratio of Mg/Al and the introduction of SDS, concentrations of PB are decreased accordingly. As a result, the rate of solar vapor generation is increased by 35.9% for powders containing 50 mg of equivalent PB. Of note, converting this material into a three-dimensional structure of high rebound foam further enhances solar water evaporation rate, from 0.79 kg m−2 h−1 to 0.98 kg m−2 h−1, with only 20 mg of equivalent PB, increasing the corresponding photothermal conversion efficiency from 53.8% to 66.3%. [ABSTRACT FROM AUTHOR]

Excessive emission of CO2 into the atmosphere has severely impacted the global ecological environment. Converting CO2 into valuable chemicals and fuels is of great significance for sustainable development. However, low activity and undesirable selectivity often result from the inherent inertness of CO2. Herein, K- or/and Zn-modified Fe-based catalysts were prepared by an incipient-wetness impregnation method for CO2 hydrogenation via a cascade reaction. The results indicate that K species exist as K2O while Zn species exist as ZnFe2O4. In the CO2 hydrogenation pathway, K2O facilitates the adsorption of CO2 and restrains the adsorption of H2, accelerating the transformation of CO2 into C2–C4 olefins rather than paraffins while Zn species promote the dispersion of Fe species, leading to improved activity. Synergistically, a K- and Zn-modified Fe-based catalyst (2Zn–10K–Fe/Al) shows excellent catalytic CO2 hydrogenation activity, achieving a CO2 conversion of 77% which is 1.8 times that (42%) of the unmodified Fe-based catalyst (Fe/Al). Our catalyst also shows a significantly promoted selectivity to C2–C4 olefins of 17% in comparison with the Fe/Al catalyst (0%). It is envisioned that such a binary effect of elements might contribute to the low-cost and industrial production of Fe-based catalysts for selective CO2 conversion. [ABSTRACT FROM AUTHOR]

Sperm DNA fragmentation is a sign of sperm nuclear damage. The sperm chromatin dispersion (SCD) test is a reliable and economical method for the evaluation of DNA fragmentation. However, the cut-off value for differentiation of DNA fragmented sperms is fixed at 1/3 with limited statistical justification, making the SCD test a semi-quantitative method that gives user-dependent results. We construct a collection of deep neural networks to automate the evaluation of bright-field images for SCD tests. The model can detect valid sperm nuclei and their locations from the input images captured with a 20× objective and predict the geometric parameters of the halo ring. We construct an annotated dataset consisting of N = 3120 images. The ResNet 18 based network reaches an average precision (AP50) of 91.3%, a true positive rate of 96.67%, and a true negative rate of 96.72%. The distribution of relative halo radii is fit to the multi-peak Gaussian function (p > 0.99). DNA fragmentation is regarded as those with a relative halo radius 1.6 standard deviations smaller than the mean of a normal cluster. In conclusion, we have established a deep neural network based model for the automation and quantification of the SCD test that is ready for clinical application. The DNA fragmentation index is determined using Gaussian clustering, reflecting the natural distribution of halo geometry and is more tolerable to disturbances and sample conditions, which we believe will greatly improve the clinical significance of the SCD test. [ABSTRACT FROM AUTHOR]

Drug delivery to ocular tissues is mainly hindered by anatomical and physiological barriers that diminish their bioavailability. In this work, layered double hydroxides (LDHs) intercalated with non-steroidal anti-inflammatory drugs (NSAIDs; ibuprofen, ketoprofen, and ketorolac) were incorporated into carboxymethylcellulose (CMC) dispersions with the aim of adjusting their rheological properties, producing sustained release, and inducing mucoadhesive properties. Pure NSAID-intercalated LDHs (LDH-NSAID) with high drug loading were obtained. The obtained particles showed high aggregation and positive surface charges, which allowed interaction with the negatively charged groups of CMC. Isotonic 1% CMC and 1% LDH-NSAID (w/w) dispersions behaved as viscous, shear-thinning fluids, although a stronger interaction with ketoprofen led to more gel-like behavior. Also, CMC/LDH-NSAID dispersions exhibited a more sustained drug release than that achieved with analogous formulations containing pure drugs, and the modeling of the profile indicated that the release rate was mainly determined by the anion exchange of the intercalated NSAID. Finally, the formulations showed strong mucoadhesion capacity, as they produce significant changes in the zeta potential of mucin dispersions. Further optimization of the particle size and surface properties of the particles is required to modulate the release profile and to enhance the rheological properties of these CMC/LDH-based formulations. [ABSTRACT FROM AUTHOR]

Herein we evaluate the promotive effect of Au and Sn incorporation into supported Pd nanoparticles for the direct synthesis of H2O2 from molecular H2 and O2. The introduction of both secondary metal modifiers was found to result in a significant enhancement in catalytic performance, although, in the case of the PdSn system, it was identified that relatively large quantities of the secondary metal were required to rival the activity observed over optimal Au-containing formulations, with the 0.25%Pd–2.25%Sn/TiO2 catalyst offering comparable H2O2 synthesis rates to the optimised 0.25%Pd–0.25%Au/TiO2 formulation. The introduction of Sn was found to considerably improve Pd dispersion, correlating with an improvement in selective H2 utilisation. Notably, the optimal PdSn catalyst identified in this work achieves superior H2O2 selectivities compared to the PdAu analogue and is able to rival the performance of state-of-the-art materials. [ABSTRACT FROM AUTHOR]

Recently, the widespread use of nanocatalytic materials has contributed to an enormous improvement in the performance of energetic materials, especially, highly dispersed nanomaterials. However, the lack of quantitative methods for analyzing the dispersion of nanomaterials limits their further widespread use. Although various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. are used to analyze the relative dispersion of nanomaterials, it is not possible to quantitatively analyze their dispersion. Therefore, there has been an effort to develop new methods for the quantitative analysis of nanocatalytic materials. Fortunately, we were able to analyze the dispersion of nanocatalytic materials using the difference in their UV absorbance. More importantly, we established the corresponding difference equation to quantify the dispersion of nanocatalytic materials, which is capable of quantifying the dispersion of nano-Fe2O3 in nano-Fe2O3–ultrafine AP composites. The accuracy of the difference equation was verified using a variety of techniques and the desired results were obtained. Based on the above conclusions, the quantitative analysis method for the dispersion of nanomaterials that we established is expected to be widely used and promote the development of energetic materials. [ABSTRACT FROM AUTHOR]

Herein, we report a comprehensive computational study to understand the stereoinduction of (R)-SEGPHOS chiral diphosphine ligand in copper(I) hydride (CuH)-catalyzed enantioselective incorporation of CO2 with styrene. Mechanistic studies disclose that the stereoselectivity of the final reductive hydroxymethylation product is collectively controlled by the steps of 1,2-hydrocupration of styrene and CO2 insertion into the Cu–C bond. The multimodal stereochemical analyses, including the topographic steric mapping of the chiral (R)-SEGPHOS-ligated CuH catalyst, distortion/interaction, and intermolecular non-covalent interaction analysis on the 1,2-hydrocupration transition states, consistently point to the steric shielding from the P-substituents of the (R)-SEGPHOS ligand to the substrate as the origin of π-facial selectivity in the 1,2-hydrocupration step. Both (R)-SEGPHOS ligands bearing the P-DMTB and P-phenyl substituents can provide sufficient steric repulsion for shielding the re-face approach of the substrate to the Cu–H bond, and thus the (S)-alkylcopper(I) intermediates could be yielded with high enantioselectivity. By contrast, the stereoselectivity of CO2 insertion into (S)-alkylcopper(I) intermediate is primarily determined by the ligand-CO2 dispersion stabilizing interaction. Relative to the (R)-SEGPHOS ligand with the P-phenyl substituents, the substantially enhanced dispersion stabilizing interactions from the P-DMTB substituents of (R)-SEGPHOS ligand to CO2 could help raise the favorability of the inner-sphere CO2 insertion into the Cu–C bond, and thus allow the construction of C–CO2 bond with outstanding stereoselectivity. [ABSTRACT FROM AUTHOR]

Nonlinear optical (NLO) materials with lone electron pairs have excellent optical properties and the introduction of F atoms is a new way to obtain NLO materials with more balanced properties. However, the research of NLO materials still faces great challenges and difficulties, especially regarding the phase-matching (PM) wavelength, which is an important parameter of NLO materials and is influenced by birefringence and refractive index dispersion. Iodates have been widely noticed as excellent NLO materials. In this work, we have selected the typical alkali metal iodates MIO3 and fluorooxoiodates MIO2F2 (M = Na, K, Rb, and Cs), and systematically explored the functional modules as well as the mechanisms regulating birefringence in iodates and fluorooxoiodates. Meanwhile, the refractive index dispersion of the above iodates and fluorooxoiodates was also analyzed. The results show that the introduction of F atoms will adjust the birefringence and refractive index dispersion. At the same time, in general, the birefringence from iodates to fluorooxoiodates is decreased, but the birefringence of NaIO2F2 is increased compared with that of NaIO3, because the anion groups in NaIO2F2 are arranged in the direction beneficial to enhancing optical anisotropy, and the direction of lone pair electrons is consistent with the optical principal axis. In terms of the refractive index dispersion, the refractive index dispersion from iodates to fluorooxoiodates is decreased because of the regulation of F atoms. This could further facilitate the design of new NLO materials with excellent properties. [ABSTRACT FROM AUTHOR]

In this study, oxidative degradation of Orange G (OG) and Eosin Y (EY) dyes with TiO2 as the catalyst was explored in air-equilibrated aqueous dispersions under UV light irradiation. To determine the optimal operating conditions for degradation, various effects were investigated, such as the pH of the dye dispersion, the addition of cationic surfactants and the specific additive. The photodegradation efficiency of both dyes was significantly enhanced at alkaline pH, particularly in the presence of tetraalkylammonium bromide surfactants, as they promote a mutual interaction between the dye and TiO2 surface, otherwise prevented due to their negative charge under basic conditions. The surfactant concentration also played an important role, because it influences the state of surfactant aggregation on the semiconductor surface. The kinetic trend of the fragmentation process was strongly affected by different hydrophobic and electrostatic interactions that OG and EY and their derivative intermediates are able to establish with surfactant/TiO2 in various forms of aggregation, as well as by their redox properties. Density functional theory (DFT) calculations of charge distribution and Gibbs free energy changes of solvation, performed on optimized molecular geometry, were useful to support and rationalize the surfactant involvement in the degradation process. [ABSTRACT FROM AUTHOR]

A polyurethane foam (PUF) was coated with a thin layer of polydopamine (PDA), and Pd strongly anchored onto PDA via simple immersion of PDA@PUF in a hydro-alcoholic solution of Pd(NH3)4Cl2·H2O at room temperature under air to afford a Pd@PDA@PUF foam. XPS showed the absence of initial reduction of palladium despite the redox properties of PDA, and HR-SEM and SEM-EDX suggested a coordination of evenly dispersed Pd(II) ions by the catechol moieties of the PDA layer, thus resulting in a single atom-type dispersion of the active phase. The "dip-and-play" catalytic pattern of Pd@PDA@PUF and high dispersion of Pd on the surface guaranteed high activity, selectivity and reusability in alkyne semi-hydrogenation and in Suzuki coupling under air without prior reduction procedures. Self-enhancing properties, observed in recycling and control experiments, were explained by XPS as the chelated Pd(II) ions were gradually reduced to isolated coordinated Pd(0) atoms under hydrogenation or Suzuki coupling reaction conditions. [ABSTRACT FROM AUTHOR]

Fluorescent organic–inorganic nanohybrids based on π-extended hydroxyoxophosphole emitters grafted onto ZnO nanocrystals, have been introduced as an efficient way to control the spatial arrangement of the organic emitters within a host material. The homogeneous dispersion of the emissive nanohybrids within a host matrix is achieved via co-grafting of an additional surfactant, leading to very smooth films with low roughness. Interestingly, the co-grafting of this surfactant not only improves the thin film morphology but also enhances its photoluminescence quantum yield and allows for the easy solution-processing of this material as an emissive layer in a simplified OLED structure. These devices display strongly improved performances, by more than one order of magnitude, compared to OLEDs using pure nanohybrids. These promising results prove the potential of this technique to graft any type of luminophore in efficient solution-processed light-emitting devices. [ABSTRACT FROM AUTHOR]

In this study, we constructed multi-dimensional CoFeO x catalysts for the catalytic oxidation elimination of o-dichlorobenzene (o-DCB). The dimension of the catalyst was modulated to promote the dispersion of components and thus improve the surface active oxygen species. The effects of the multi-dimensional CoFeO x catalysts on surface active oxygen species and the o-DCB elimination performance were investigated. The temperatures of o-DCB catalytic oxidation with 90% conversion (T90) over the 2D/1D CoO x /CoFeO x , 2D CoFeO x and 2D/1D CoFeO x /CoO x catalysts were 395, 405, and 365 °C, respectively. The results showed that the oxygen vacancies of the 2D/1D CoFeO x /CoO x catalysts were enhanced due to the multi-dimensional effect compared to 2D CoFeO x . The outstanding catalytic activity and thermal stability of 2D/1D CoFeO x /CoO x were mainly attributed to its large specific surface area, pore volume and pore size, more Co3+ content, excellent reducibility, large number of surface adsorbed oxygen (Osur) species and rich oxygen vacancies. [ABSTRACT FROM AUTHOR]

Three cadmium(II) coordination polymers, namely {[Cd(HLI)(NO3)2]·0.5MeOH}n (1), {[Cd(HLII)(NO3)2]·EtOH}n (2), and [Cd2(LII)2(NO3)2]n (3), have been self-assembled from Cd(NO3)2 and N,N′,O-pincer-type isonicotinoylhydrazone-based ditopic ligands (HLI = N′-(pyridin-2-ylmethylene)isonicotinohydrazide and HLII = N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide) and have been characterized experimentally and by DFT computations. In compounds 1 and 2, the corresponding ligand is coordinated to the metal center in the keto form and acted as a tetradentate chelating–bridging agent in which the nitrogen atom of the 4-pyridine ring is coordinated to the cadmium center of the neighboring unit, yielding 1D zig-zag coordination polymers. In compound 3, the ligand was singly-deprotonated and is coordinated in the enolic form with the nitrate ion further acted as a bridging agent, yielding a 2D network. It is revealed by the extended transition state natural orbital for chemical valence (ETS-NOCV) charge and energy decomposition scheme that typical hydrogen bonds O–H⋯O and N–H⋯O, which constitute the networks of 1 and 2, though dominated by a classic Coulomb term, are characterized by an equally important London dispersion constituent due to extra π⋯π and C–H⋯X contacts (X = O, H–C, H–N). The architecture of 3 is due to ionic and dative-covalent Cd–X (X = N, O) bonds as well as London dispersion-driven homopolar dihydrogen C–H⋯H–C and C–H⋯O interactions. NOCV-based representation allowed us to determine that hydrogen bonds O–H⋯O are twice weaker than the corresponding N–H⋯O in the networks of 1 and 2. [ABSTRACT FROM AUTHOR]

Using a combination of NMR, single crystal X-ray diffraction (sc-XRD) and quantum chemistry, the structure-directing role of London Dispersion (LD) is demonstrated for dibismuthane Bi2Naph2 (1). 1 shows intermolecular Bi⋯π contacts in the solid-state, while π⋯π interactions as observed in the lighter homologues are missing. Comparison of the whole series of dipnictanes revealed the influence of the pnictogen atom on the strength of London dispersion and highlights its importance in heavy main group element chemistry. [ABSTRACT FROM AUTHOR]

Effective dispersion of carbon nanotubes (CNTs) is of great importance to achieve their intrinsic performance. Normally, it is believed that CNT dispersion is decided by interactions between CNTs and their dispersants, while other interactions are often neglected. Herein, three ionic surfactants, sodium dodecyl sulfate (SDS), dodecyl dimethyl betaine (BS-12) and cetyltrimethylammonium bromide (CTAB), are used to disperse CNTs in a ternary composite, i.e., poly(p-phenylenediamine)-phosphomolybdic acid@reduced graphene oxide (DMoG), respectively, leading to three different DMoGC composites. It has been found that the CNT dispersion in DMoGC was mainly controlled by electrostatic interactions between the surfactants and DMoG, which further exerted vital influences on the constitution, content, morphology, porous structure and supercapacitive performance of the DMoGC composites. Among the three surfactants, cationic CTAB showed the best CNT dispersion, while amphoteric BS-12 could hardly disperse CNTs in DMoGC, leading to DMoGC-CTAB with a 2 times larger specific surface area (152.3 m2 g−1) and 1.5 times higher specific capacitance (422 F g−1) than those of DMoGC-(BS-12). Our study can provide valuable guidelines for selecting/designing effective dispersants to prepare multi-component composites containing uniformly dispersed CNTs. [ABSTRACT FROM AUTHOR]

Herein, Cu/ZrO2 catalysts containing different Cu contents with or without La-doping were used for the selective hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). Effects of La addition and the optimal Cu content were thoroughly investigated. It was found that the Cu0/Cu+ pairs located at interfacial sites for CuO/ZrO2 catalysts with different Cu contents played an important role in the hydrogenation of DMO to EG. Interestingly, the La-doping could make the copper dispersion increase obviously. Besides, it greatly inhibited the crystal phase transformation from tetragonal to monoclinic zirconia regardless of being calcined at 750 °C. Meanwhile, the incorporation of La promoted the activation of hydrogen although resulting in a small increase in acidic/basic sites over the catalyst surface, which led to a higher conversion of DMO while the selectivity of EG decreased slightly. As a result, 97.2% selectivity of EG, which corresponds to 100% conversion of DMO, was achieved over the La-doped CuO/ZrO2 catalyst with 33 wt% Cu content, which was also stable for more than 168 h on stream. This results revealed that the strong interaction between La promoters and Cu species was another type of important active site with high catalytic efficiency in addition to the Cu0/Cu+ site of La-doped CuO/ZrO2 catalyst. [ABSTRACT FROM AUTHOR]

The perfluorinated alkoxy silanes {(F3C)3CO}3SiH (1) and {(F5C6)3CO}2Si(Cl)H (2) were prepared and fully characterized. Despite the high calculated Brønsted acidities, all attempts to deprotonate 1 and 2 to give the conjugate silanide ions failed due to the exceptionally short and strong Si–H bonds. In the solid state, the Si–H units are not involved in any intermolecular interactions, but instead the crystal packing consists of exceptionally short and strong F⋯F interactions. The cohesive energies are entirely comprised of London dispersion interactions, similarly as in the crystal structures of noble gases. [ABSTRACT FROM AUTHOR]

Formaldehyde oxidation at room temperature with low-cost catalysts is one of the main development directions of environmental governance. Herein, we developed a low-cost and superior performance highly dispersed Ce on Na-ZSM-5 (Ce/Na-ZSM-5) catalyst, which is close to atomic dispersion for indoor formaldehyde (HCHO) oxidation at low temperature. The highly dispersed catalyst that was similar to atomic dispersion was characterized by EXAFS and AC HAADF-STEM. The optimal Ce/Na-ZSM-5 displays high HCHO removal performance (95%, at room temperature), as well as 100 h stable testing (∼90% HCHO removal). In addition, a reasonable reaction mechanism of the HCHO catalytic oxidation is proposed based on the in situ DRIFT spectra and DFT calculation. This work provides a new way to design an efficient catalyst for the complete oxidation of formaldehyde. [ABSTRACT FROM AUTHOR]

Herein, Pt nanoparticles supported on a polymer substrate are electrochemically synthesized and used for methanol electrooxidation in alkaline media. The effect of the cocatalyst, supporting materials, and electrodeposition mode on the improvement in the electrocatalytic activity of Pt nanoparticles towards methanol oxidation is investigated. The electrochemical experiments demonstrate that ternary nanoparticles supported on the polymeric substrate through the pulse electrodeposition technique (p-Pt/NiCu/p-MDAB/MWCNT) boost the methanol oxidation reaction (MOR). The MOR enhancement can result from an improvement in the size, dispersion, and porosity of metallic nanoparticles. This study implies that an appropriate selection of the cocatalyst and preparation method is promising for the design and fabrication of profitable electrocatalysis. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of CO2 with non-precious materials containing the Co–N–C moiety as a catalyst is considered to be a promising method to achieve carbon neutrality. Unfortunately, metal phthalocyanines with an intrinsic Co–pyrrolic N4–C structure usually show low electrocatalytic activity due to serious aggregation and low conductivity. Here, we exhibit a simple strategy to controllably disperse cobalt phthalocyanine (CoPc) on graphene oxide (GO) by the hydrolysis of protonated CoPc in GO aqueous phase. CoPc/GO nanocomposites with different ratios and structures could be easily obtained, and their effect on the electrocatalytic activity for the CO2 reduction reaction (CO2RR) to CO was systematically investigated. In the optimal sample, a CO selectivity of >96% can be achieved with an overpotential of <190 mV. Meanwhile, a CO Faradaic efficiency (FECO) of >90% can be reached within a wide potential range from −0.7 to −1.0 V (vs. RHE). The systematical experiments reveal that the synergy of CoPc and GO should be crucial owing to the existence of strong electrostatic interactions at the initial stage of hydrolysis and subsequent π–π, hydrogen bond and axial coordination interactions between CoPc and GO. This work exhibits a simple strategy to prepare molecule-based nanostructures as highly efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

The conversion of CO2 into value-added chemicals has attracted a lot of attention, not only reducing the concentration of CO2 in the air, but also generating chemicals and fuels, which are of great importance to solve the growing environmental and energy problems. Ni catalysts with different Zr/Al ratios were prepared by co-precipitation and impregnation for CO2 methanation. The activity test results showed that almost 100% CH4 selectivity and 82.6% CO2 conversion were obtained at a reaction temperature of 350 °C when the Zr/Al ratio was 1. The physicochemical properties of the catalysts were investigated using XRD, N2 adsorption–desorption, H2-TPR, H2-TPD, CO2-TPD, XPS and TEM, and the surface-generating substances and methanation reaction mechanism of the catalysts were explored using in situ DRIFTS characterisation. The experimental results show that the addition of Al2O3 to Ni/ZrO2 weakens the Ni–ZrO2 interaction and promotes the reduction and dispersion of NiO through the solid solution bonding of ZrO2–Al2O3. The in situ DRIFTS results show that there are more formate adsorbed species on the surface of the Ni/ZrO2–Al2O3 catalyst compared to the Ni/ZrO2 catalyst, which is the main formation substance for CO2 methanation. [ABSTRACT FROM AUTHOR]

A spinel-alumina inert oxide supported gold catalyst with high Au dispersion and excellent CO oxidation activity was developed by a deposition–precipitation method. The activation atmosphere could tune the reaction pathway by adjusting the amount of surface adsorbed water species, thus transforming the reaction intermediates from HCO3− or CO32− to COOH. [ABSTRACT FROM AUTHOR]