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Single‐atom catalysts (SACs) have emerged as crucial players in catalysis research, prompting extensive investigation and application. The precise control of metal atom nucleation and growth has garnered significant attention. In this study, we present a straightforward approach for preparing SACs utilizing a photocatalytic radical control strategy. Notably, we demonstrate for the first time that radicals generated during the photochemical process effectively hinder the aggregation of individual atoms. By leveraging the cooperative anchoring of nitrogen atoms and crystal lattice oxygen on the support, we successfully stabilize the single atom. Our Pd1/TiO2 catalysts exhibit remarkable catalytic activity and stability in the Suzuki–Miyaura cross‐coupling reaction, which was 43 times higher than Pd/C. Furthermore, we successfully depose Pd atoms onto various substrates, including TiO2, CeO2, and WO3. The photocatalytic radical control strategy can be extended to other single‐atom catalysts, such as Ir, Pt, Rh, and Ru, underscoring its broad applicability. [ABSTRACT FROM AUTHOR]

The effect of K on the distribution and productivity of the olefins in CO2 hydrogenation over the single‐walled carbon nanotubes (SWNTs) supported Fe catalysts was systematically investigated. The promotion of K not only effectively suppressed the formation of the undesired light paraffins (CH4 and C20−C40), but also significantly affected the distribution and the productivity of the olefins. The highest selectivity and productivity of light olefins (C2=−C4=) of 27 % and 16 μmolCO2 gFe−1 s−1, respectively, were obtained at 7 wt% of K, while the highest selectivity and productivity of heavy olefins (C5+=) of 40 % and 27 μmolCO2 gFe−1 s−1, respectively, were obtained at 3 wt% of K under the same reaction conditions. At 3 wt% of K and above, the overall selectivity to the olefins (inclusive of light olefins and heavy olefins) remained at as high as ca. 60 % at high CO2 conversion of ca. 50 %. Comprehensive characterizations revealed that the K promoter enhanced the basicity of the catalyst, which facilitates the formation of χ‐Fe5C2, the key active phase for CO2 hydrogenation. A good linear relationship is established between the surface basicity and the content of χ‐Fe5C2. Moreover, the K promoter weakened the adsorption of the olefins, which inhibited the secondary hydrogenation of the olefins, thus improving the selectivity to the olefins. This work demonstrates that K is a highly promising promoter for the tailoring of the types of the olefinic products in CO2 hydrogenation. [ABSTRACT FROM AUTHOR]

The design of robust solid catalysts which can selectively synthesize highly functionalized carbohydrate derivatives from unprotected and unactivated simple sugars in water is an outstanding challenge. Herein we describe the preparation of a novel nanospherical ordered mesoporous Lewis acid polymer (Sc(OTf)2-NSMP) by functionalizing the mesoporous phenol-formaldehyde polymer framework with scandium triflate groups. In the C-glycosylation reaction between D-glucose and dimedone with the Sc(OTf)2-NSMP catalyst, the conversion was 99 % and the yield of xanthone- C-glucoside reached 92 % after 2 days, which exceeded the previous best results. It was shown that other xanthone glycosides can be obtained from various sugars with moderate to good yields. Furthermore, the catalyst can be easily recovered and reused at least seven times without loss of catalytic activity. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) over metal catalysts represents an economically feasible method to convert the greenhouse gas CO 2 into valuable chemical products. Owing to the strong stability of both CH 4 and CO 2 molecules, the reaction usually occurs at very high temperatures, so that the key problem of the reaction is catalysts agglomeration. In this study, we developed a novel core-shell Ru@SiO 2 catalyst by encapsulating Ru nanoparticles in SiO 2 shells through a reversed-phase microemulsion method. The as-produced core-shell Ru@SiO 2 catalyst effectively enhanced the thermal stability of the Ru nanoparticles against gathering at high temperatures, owing to the confinement effect of the SiO 2 shells on the Ru nanoparticles and a sturdy support-metal interaction. Thus, the developed catalyst exhibited a longer lifetime than those of both the unsupported Ru and traditional Ru/SiO 2 catalysts. More importantly, the ultrafine Ru nanoparticles provided both abundant active sites and high instinct activity. Further more, the ultrafine Ru nanoparticles also inhibited carbon generation, thereby preventing catalyst deactivation. To the best of our knowledge, this as-produced core-shell Ru@SiO 2 is one of the best DRM catalysts at high space velocities reported to date. [Display omitted] A novel core-shell Ru@SiO 2 catalyst was developed, which exhibited excellent activity and durability for CO 2 conversion via dry reforming of methane. • Ru@SiO 2 core-shell structured catalyst. • CO 2 conversion to syngas via dry reforming of methane (DRM). • High activity and absolute selectivity. • Inhibition of Ru agglomeration and carbon deposition. • Long lifetime in DRM at 700 oC. [ABSTRACT FROM AUTHOR]

Abstract: Uniform spherical Co-B amorphous alloy nanoparticles were prepared by ultrasound-assisted reduction of Co(NH3)2+ 6 with BH− 4 in aqueous solution, and the particle size was adjusted by changing either the ultrasound power or the ultrasonication time. During liquid-phase cinnamaldehyde (CMA) hydrogenation, the as-prepared Co-B catalyst exhibited much higher activity and better selectivity to cinnamyl alcohol (CMO) than the regular Co-B obtained by direct reduction of Co2+ with BH− 4. The higher activity can be attributed to both the higher dispersion of Co active sites () and the higher intrinsic activity (). The higher selectivity can be attributed to both the uniform Co-B amorphous alloy particles and the strong electronic interaction between Co and B, which enhances the competitive adsorption of Cgainst Cn the CMA molecule. Meanwhile, the stronger adsorption for hydrogen on Co active sites was more favorable for Cnation in comparison with the Cnation. [Copyright &y& Elsevier]

Abstract: Mesoscopically spherical Ni–B amorphous alloy nanoparticles were prepared through self-assembly of an ionic surfactant hexadecyltrimethylammonium bromide. During liquid-phase nitrobenzene hydrogenation, the as-prepared mesoporous Ni–B catalyst exhibited higher activity and selectivity than the regular Ni–B obtained via direct chemical reduction, apparently owing to the higher surface area, which ensured high dispersion of active sites and the mesoporous channels that might facilitate diffusion and adsorption of reactant molecules. [Copyright &y& Elsevier]

The Ni-B and Co-B amorphous alloys exhibited much higher activity and selectivity to ethylamine (C2H5NH2) than their corresponding crystallized counterparts and Raney Ni during liquid phase hydrogenation of acetonitrile (CH3CN). In comparison with the Ni-B amorphous alloy, the Co-B amorphous alloy exhibited longer lifetime and better selectivity, though its activity was slightly lower. The maximum yield of C2H5NH2 could reach 93.5%, showing a good potential in industrial application. The higher activity of the amorphous alloys could be attributed to the large active surface area, the unique amorphous structure together with the suitable structural parameters, and the electron donation of the alloying B to the metallic Ni or Co. The resulted electron-enriched metallic active sites may also account for the better selectivity to C2H5NH2 of the amorphous alloys since, on one hand, it could promote the hydrogenation of CH3CH&z.dbnd6;NH toward C2H5NH2 by activating the C&z.dbnd6;N bond; and on the other hand, it may retard the condensation between CH3CH&z.dbnd6;NH and C2H5NH2 leading to (C2H5)2NH by inhibiting the adsorption of C2H5NH2 which was essential for the condensation. The Co-B amorphous alloy was more selective than the Ni-B owing to its stronger adsorption for CH3CN and the higher electron density on the Co active sites, both of them could inhibit the adsorption for C2H5NH2 and in turn, retard the condensation. This could also account for its longer lifetime. However, such stronger adsorption for CH3CN was harmful for the competitive adsorption for hydrogen and in turn resulted in a slightly lower hydrogenation activity than the Ni-B since the CH3CN hydrogenation was first-order with respect to hydrogen while zero-order to CH3CN. [Copyright &y& Elsevier]

The La-doped Co-B/SiO2 amorphous catalyst (Co-La-B/SiO2) was prepared by chemical reduction of mixed Co2+ and La3+ ions deposited on a silica support with KBH4 aqueous solution at room temperature. The catalyst was employed in the liquid phase hydrogenation of cinnamaldehyde (CMA) to cinnamyl alcohol (CMO). At suitable content, the La-additives exhibited promoting effects on both the activity and the selectivity to CMO. The optimum La-content (χLa) was determined as 0.014 (molar fraction), over which the CMO yield could reach 80%. Based on various characterizations, the promoting effect of the La-dopant on the selectivity to CMO was mainly attributed to the presence of La2+ and La3+. These La-species were favorable for both the activation of the C&z.dbnd6;O bond and the formation of H− species and thus, promoted the hydrogenation of C&z.dbnd6;O bond. These roles also promoted the hydrogenation activity. Besides, the promoting effect of the La-dopant might also attributed to the presence of the La oxides which increased the surface Co active sites. At high χLa, the activity decreased again due to the coverage of the Co active sites by the inactive La-additives and also due to the too strong adsorption of carbonyl group induced by La3+ and La2+. Such strong adsorption might hinder the competitive adsorption of hydrogen. [Copyright &y& Elsevier]

Photothermal catalysis of CO 2 hydrogenation holds great potential in achieving carbon neutrality. However, the rational design of cost-effective photothermal catalysts with high performance for CO 2 hydrogenation is an ongoing challenge. Herein, we employed CuCo y BOₓ composite catalysts by incorporating both CuBOₓ and amorphous CoBOₓ to efficiently catalyze the CO 2 hydrogenation. Besides the high selectivity (98.0%), the optimized CuCo 5 BO x demonstrated a remarkable CO yield of 124.7 mmol g⁻¹ h⁻¹ under illumination at 300°C, which was 3 times higher than the traditional thermocatalysis. Experimental results and theoretical calculations demonstrated CuBOₓ acted as a photocatalyst, donating electrons to CoBOₓ active sites. Coupling boron-oxygen species with CuCo bimetallic-oxides synergically enhanced the CO 2 adsorption capacity and accelerated charge transfer, thereby enhancing the photothermal synergistic effect and consequently boosting the catalytic activity. This study establishes an approach for the rational design of non-precious metal-boride catalysts, enabling efficient photothermal conversion of CO 2 into CO under mild conditions. [Display omitted] • CuCo y BOₓ photothermo-bifunctional catalyst. • 3 times higher activity than the thermal catalyst in CO 2 hydrogenation. • Promoting from coupling boron-oxygen species with CuCo bimetallic oxides. [ABSTRACT FROM AUTHOR]

Abstract: Ce-doped Pd–B amorphous alloy catalysts were prepared by chemical reduction of mixed PdCl2 and Ce(NO3)3 with KBH4. During liquid-phase selective hydrogenation of phenol to cyclohexanone, the as-prepared Pd–Ce–B catalysts exhibited much higher activity, better selectivity and excellent durability than the undoped Pd–B. Based on various characterizations, the promoting effect of Ce-dopant on the catalytic properties can be addressed as follows: (1) stabilizing the amorphous structure of Pd–B alloy and enhancing the dispersion degree of Pd active sites; (2) increasing the electron density of Pd, which could enhance hydrogenation activity and improve catalytic durability; (3) increasing the surface basicity, which facilitated the non-planar adsorption of phenol on catalyst surface, leading to higher cyclohexanone selectivity. [Copyright &y& Elsevier]

Abstract: Au/TiO2 catalysts prepared by the deposition–precipitation method showed excellent activity and selectivity in the oxidative cyclization of 1,4-butanediol to γ-butyrolactone, with high yields (>99%) under mild conditions (413 K, 1.25 MPa air). Catalysts with 3–8% gold loading and calcined at 573–673 K were all highly active for the formation of γ-butyrolactone, as demonstrated by XRD, TEM, XPS, ICP and UV–vis DRS results. It is concluded that highly dispersed small (2–10 nm) gold particles are formed with the surface enrichment of gold. The ratio of cationic gold to metallic gold depends on the treatment temperature. These findings, combined with those of the activity tests, lead to the conclusion that the surface metallic nanosized gold particles are active sites. The catalyst can be reused with no drop in activity or selectivity. [Copyright &y& Elsevier]

Selective oxidation of CH 4 by O 2 to produce CH 3 OH under mild reaction conditions is of importance but remains a significant challenge. Herein, we report a novel nanocomposite of highly dispersed Au and Fe species on ZnO (AuFe-ZnO). During photocatalytic O 2 oxidation of CH 4 to CH 3 OH, this AuFe-ZnO acts as a bifunctional catalyst to drive one-pot cascade reactions (O 2 + H 2 O → H 2 O 2 and CH 4 + H 2 O 2 → CH 3 OH + H 2 O). The ZnO semiconductor generates electrons under irradiation to produce H 2 O 2 from O 2 , in which the photo-induced holes could activate CH 4 to form •CH 3. The Au served as a co-catalyst for activating CH 4 , while the Fe2+ species catalyzed Fenton-like reactions by activating H 2 O 2 to form •OH radicals, followed by reacting with •CH 3 to produce CH 3 OH. The synergetic effects of Au, Fe, and ZnO result in a high CH 3 OH yield of 1365 μmol·g−1·h−1 with high CH 3 OH selectivity of up to 90.7%. [Display omitted] • Novel bifunctional AuFe-ZnO catalysts to drive one-pot cascade reactions were developed. • H2O2 were in situ formed from O2 and then activated during the CH4 oxidation reaction. • The synergetic effects of photocatalytic reactions and Fenton-like reactions enhanced the CH3OH yield and selectivity. [ABSTRACT FROM AUTHOR]

Review: 228 refs. [ABSTRACT FROM AUTHOR]

Abstract: A periodic mesoporous organogold(I)silica catalyst was synthesized by surfactant-directed co-condensation of Au[PPh2(CH2)2Si(OCH2CH3)3]2Cl and (CH3CH2O)3SiPhSi(OCH2CH3)3. The as-prepared Au–PPh2–PMO(Ph) contained ordered mesopore channels with both phenyl (Ph) group and Au(I) organometal homogeneously embedded in silica walls. Such catalyst exhibited higher activity than free Au(PPh3)Cl in hydration reactions of various terminal alkynes. This could be mainly attributed to the high surface area, the ordered mesoporous channels and the enhanced surface hydrophobility, which facilitated the diffusion and adsorption of reactants. Meanwhile, the unique coordination model between Au(I) and (PPh2) was also favorable for the alkyne hydration. Besides the high activity, the catalyst could be easily recycled and used repetitively owing to the high hydrothermal stability and the stabilized Au(I) active sites against leaching. [Copyright &y& Elsevier]

Abstract: Copper-containing mesoporous silica HMS catalysts were prepared by an impregnation method. The surface structures of these catalysts were characterized by N2-physisorption, X-ray diffraction, transmission electron microscopy, H2 temperature-programmed reduction, Fourier transform infrared spectroscopy, N2O titration and X-ray photoelectron spectroscopy. The results show that the copper-containing HMS catalysts exhibit superior catalytic performance in the selective hydrogenation of dimethyl oxalate to ethylene glycol compared to the commercial silica-supported ones obtained by the same method. The dimethyl oxalate conversion can reach 100% and the ethylene glycol selectivity can reach 92% at 473K with 2.5MPa H2 pressure and 0.2h−1 liquid hour space velocity of dimethyl oxalate over the 5wt.% Cu-HMS catalyst. The enhanced catalytic performance of copper-HMS catalysts may be attributed to the homogeneous dispersion and uniformity of the active copper species and to the larger copper surface areas attained on the HMS supports with large pore diameters and surface areas. [Copyright &y& Elsevier]

Uniform Co–B nanoparticles were synthesized for the first time by chemical reduction of cobalt ion with borohydride in an oil-in-water microemulsion system comprising cyclohexane, polyethylene glycol, and water. The particle size was controlled by modulating the cyclohexane content. With the characterization of X-ray diffraction, selective area electronic diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy, the resulting Co–B nanoparticles were identified to be amorphous alloys ranging in size from 6 to 20 nm. During liquid-phase cinnamaldehyde hydrogenation, the as-synthesized Co–B catalyst was extremely active and more selective than the regular Co–B prepared in aqueous solution. Furthermore, this catalyst also was found to be more durable during the hydrogenation process. [Copyright &y& Elsevier]

Abstract: Selective oxidation of cyclopentane-1,2-diol to glutaric acid (GAC) over different kinds of materials has been carried out with aqueous hydrogen peroxide. The homogenous tungstic acid catalyst was tried first, which showed a yield of GAC as high as 91.2%. However, the separation, recovering and reusing of the homogeneous catalyst are very difficult, thus restricting its further application in industry. Then tungsten-containing mesoporous silica (W-MCM-41) was next tried as a heterogeneous catalyst. Although the activity was about 20% lower than that of the homogeneous one, it was much more easily to be separated, recovered and reused. It is interesting to find that the phase-transfer material shows the best performance in the reaction, during which the yields of GAC on [π-C5H5NC16H33]2{W2O3[O2]4} (CW) and [π-C5H5NC16H33]3{PO4[WO3]4} (CPW) were 91.3 and 94.3%, respectively. These two materials demonstrated the characteristic features of “reaction-controlled phase-transfer”; the samples dissolved during the reaction and precipitated after the reaction. Therefore, these materials show the advantages of both homogeneous and heterogeneous catalysis and can easily be recovered and reused. The fresh samples and the recovered ones were all characterized by FT-IR, Raman, 31P NMR and XPS spectroscopy. The structures of these two materials all changed after the reaction, polymerizing by forming W–Oc–W (edge-sharing) bonds. XPS results revealed that the recovered samples of CW and CPW are all more stable than the corresponding fresh ones due to the changes of the coordination circumstances. [Copyright &y& Elsevier]

Abstract: Skeletal Ni catalysts (RQ Ni) prepared by alkali leaching of rapidly quenched Ni–Al alloys have been systematically characterized, focusing on the effect of the cooling rate during alloy preparation. It is found that the residual Al content, texture, structure, surface hydrogen species, and active sites of the RQ Ni catalysts can be controlled by the cooling rate of the Ni–Al alloys. In liquid-phase hydrogenation of 2-ethylanthraquinone (eAQ), the RQ Ni catalyst with higher cooling rate favors hydrogenation of the carbonyl group and retards the saturation of the aromatic ring and the formation of the degradation products, thus leading to a higher yield of H2O2. Based on the characterizations, the improved selectivity is ascribed to the dominant population of strongly chemisorbed hydrogen, which is inactive for the hydrogenation of the aromatic ring, along with the electronic interaction between residual metallic Al and Ni, favoring a carbonyl group-bonded configuration of eAQ on the catalyst. [Copyright &y& Elsevier]

Abstract: In the present work, we demonstrate for the first time the use of W-doped SBA-15 catalyst prepared by a novel in situ synthesis method as highly efficient catalyst for the direct production of glutaraldehyde via selective oxidation of cyclopentene by using non-aqueous hydrogen peroxide as the green oxidant. It is suggested that the presence of a high surface concentraiton of WO x species dispersed on well ordered hexagonal pore walls of SBA-15 support is essential to the superior performance of the catalyst for the selective oxidation of cyclopentene. [Copyright &y& Elsevier]

Abstract: Liquid-phase hydrogenation of 2-ethylanthraquinone to 2-ethylanthrahydroquinone has been investigated over Raney Ni, nanosized amorphous Ni–B, and chromium-modified Ni–B catalysts. It has been found that the amorphous Ni–B and chromium-modified Ni–B catalysts exhibited superior selectivity, whereas the chromium-modified Ni–B catalysts had better activity and selectivity than unmodified Ni–B catalyst. Based on the characterizations, the higher selectivity of the amorphous catalysts is ascribed to the dominant population of the strongly bound hydrogen, which is not reactive for the hydrogenation of the aromatic ring, along with the repulsive interaction between the aromatic ring and the electron-rich Ni due to electron donation from alloying B. The addition of chromium decreased the particle size of the amorphous catalysts, which is beneficial for the improvement of activity. Moreover, surface chromium oxide can function as a Lewis acid, which lowers the orbital of the reactant, favoring a carbonyl group-bonded configuration. The best selectivity was achieved over the Ni–Cr–B2 catalyst, where the hydrogenation of the aromatic ring was thoroughly blocked before the saturation of the carbonyl groups. [Copyright &y& Elsevier]

A colloidal RuB/Al2O3·xH2O catalyst has been synthesized through a combined coprecipitation–crystallization–reduction strategy and characterized in detail with techniques including ICP-AES, N2 physisorption, XRD, TG/DTA, PSD and TEM. The catalytic behavior in liquid phase selective hydrogenation of benzene to cyclohexene was studied and compared with that of the RuB/γ-Al2O3 catalyst prepared by the incipient-wetness impregnation method. The RuB/Al2O3·xH2O catalyst is found more reactive than the RuB/γ-Al2O3 catalyst, and the maximum yield of cyclohexene is about four times as high as that over the latter. The better activity of the colloidal catalyst is assigned to the higher dispersion of the smaller RuB particles, whereas its superior selectivity is attributed to the improved hydrophilicity due to higher content of structural water and surface hydroxyl groups. [Copyright &y& Elsevier]

The textural and structural properties of a skeletal Ni catalyst prepared by alkali leaching of aluminum from the rapidly quenched Ni50Al50 alloy have been investigated by elemental analysis (ICP-AES), nitrogen physisorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and H2 thermal desorption techniques. As compared to Raney Ni, such a skeletal catalyst has a residual Ni2Al3 phase, lower surface area, higher average pore diameter and porosity, larger mean crystallite size, and unit-cell parameter. These differences are attributable to the metastable character of the pristine rapidly quenched alloy and their relationship with the catalytic behavior is discussed and correlated. [Copyright &y& Elsevier]

• Sn-doped Co 3 O 4 nanorods was used as CO oxidation catalyst. • Only Co2+ in the lattice of Co 3 O 4 were substituted by Sn4+. • This catalyst displayed low-temperature activity (T 100 ∼ −100 °C). • This catalyst possessed excellent stability at ambient temperature. Catalytic oxidation of CO at ambient temperature is an important reaction for many environmental applications. Here, we employed a defect engineering strategy to design an extraordinarily effective Sn-doped Co 3 O 4 nanorods (NRs) catalyst for CO oxidation. Our combined theoretical and experimental data demonstrated that Co2+ in the lattice of Co 3 O 4 were substituted by Sn4+. Based on a variety of characterizations and kinetic studies, this catalyst was found to combine the advantages of the nanorod-like morphology for largely exposing catalytically active Co3+ sites and the promotional effect of Sn dopant for adjusting the textural/redox properties. Additionally, the Sn-substituted Co 3 O 4 NRs can be further activated via heat treatment to achieve low-temperature CO oxidation (T 100 ∼ −100 °C) with excellent stability at ambient temperature. This study reveals the importance of Sn-substitution of inactive Co2+ in Co 3 O 4 and provides an ultra-efficient catalyst for CO oxidation, making this robust material one of the most powerful catalysts available up to now. [ABSTRACT FROM AUTHOR]