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Controlled synthesis of twinning β-phase anhydrous guanine nanoplatelets is realized for the first time in an aqueous solution via ammonia volatilization.

N-doped porous carbon coated CoFe@Pt nanoparticles were constructed and exhibited low Pt content, outstanding mass activity and specific activity, exceptional resistance to CO toxicity, and good stability for the methanol oxidation reaction.

The development of cold-adapted enzymes with high efficiency and good stability is an advanced strategy to overcome the limitations of catalytic medicine in low and cryogenic temperatures. In this work, inspired by natural enzymes, a novel cold-adapted nanozyme based on a manganese-based nanosized metal-organic framework (nMnBTC) is designed and synthesized. The nMnBTC as an oxidase mimetic not only exhibits excellent activity at 0 °C, but also presents almost no observable activity loss as the temperature is increased to 45 °C. This breaks the traditional recognition that enzymes show maximum activity only under specific psychrophilic or thermophilic condition. The superior performance of nMnBTC as a cold-adapted nanozyme can be attributed to its high-catalytic efficiency at low temperature, good substrate affinity, and flexible conformation. Based on the robust performance of nMnBTC, a low-temperature antiviral strategy is developed to inactivate influenza virus H1N1 even at -20 °C. These results not only provide an important guide for the rational design of highly efficient artificial cold-adapted enzymes, but also pave a novel way for biomedical application in cryogenic fields.

Single-atom catalysts (SACs) with complete dispersion of metal species on substrates provide the ultimate atom economy and opportunities for improved heterogenous catalysis or to develop more catal...

Complexity in strongly correlated oxides such as perovskite strictly dominates their performance for oxygen reduction reaction (ORR). Precise control of the physical correlations among spin, charge, orbital, and lattice degrees of freedom in these oxides can exercise considerable enhancement of ORR activity, but has until now remained elusive. Here, we show that nonmagnetic hexavalent molybdenum (Mo6+) atomically dispersed within oxide lattice steers the intrinsic activity of catalytically active sites by entrapping extrinsic electrons at their 3d orbitals, without the occurrence of lattice symmetry breaking and magnetic perturbation. With double perovskite La2Co2+Mn4+O6 as a model catalyst, the atomic-scale electron trap generates additional high-spin, catalytically active Mn3+(t32ge1g) sites and highly conductive Co2+(e2g)–O–Mn3+(e1g) double exchange channels, leading to five-fold improvement in ORR activity. First-principles calculations reveal a substantial increase of the spin density on Mn sites caused by electron trapping, and unambiguously confirm a more exothermic reaction pathway as well as a lower barrier of the rate-limiting surface hydroxide regeneration on Mo1/La2CoMnO6. We can also extend this strategy with atomic precision easily to other four oxide catalysts and achieve large enhancement in their ORR activities as anticipated, indicating its broad utility. This work embodies the theories of condensed matter physics in rational design of ORR catalysts, and may inspire further development of the control of electron correlation in strongly correlated electron systems.

A supported alkaline imidazolium ionic liquid catalyst with an ionic liquid shell and polystyrene core was synthesized. The core–shell structure was achieved by swelling polymerization of 4-vinylbe...

Recently, CO2 hydrogenation for the controlled growth of the carbon chain to produce high-value C2 or C2+ products has attracted great interest, where achieving high selectivity for a specific product remains a challenge, especially for ethanol. Herein, we have designed a bifunctional Ir1-In2O3 single-atom catalyst, integrating two active catalytic centers by anchoring the monatomic Ir onto the In2O3 carrier. This Ir1-In2O3 single-atom catalyst is efficient for the hydrogenation of CO2 in liquid, yielding a high selectivity for ethanol (>99%) with an excellent initial turnover frequency (481 h-1). Characterization shows that the isolated Ir atom couples with the adjacent oxygen vacancy forming a Lewis acid-base pair, which activates the CO2 and forms the intermediate species of carbonyl (CO*) adsorbed on the Ir atom. Coupling this CO* with the methoxide adsorbed on the In2O3 forms a C-C bond. The strategy of this effective bifunctional single-atom catalyst by synergistically utilizing the distinct catalytic roles of the single-atom site and the substrates provides a new avenue in catalyst design for complex catalysis.

A novel ionic liquid immobilized on a magnetic polymer microsphere catalyst is reported in this paper. The obtained core-shell-shell catalyst consisted of magnetic nanoparticles (MNPs) as the core, catalytic inert St-co-DVB as the intermediate protective layer, and cross-linked polyaryl imidazole ionic liquids as the active catalytic layer located at the outermost [Im[OH]/MNPs@P(St-DVB)@P(VBC-DVB)]. This catalyst exhibited a high ion-exchange rate (64.65%), high saturation magnetic strength, and excellent acid and alkali corrosion resistance. In the catalyzed Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate, the conversion of benzaldehyde maintained at 92.1% during six times reuse. Optimizing the materials of the protective layer and regulating the thickness of the inert protective layer decreased the corrosion ratio of MNPs in acidic media from 44.82 to 0.44%. Adjusting the thickness of the catalytic layer realized excellent catalytic activity (97%) and high magnetic response performance. In summary, introducing an inert protective layer to the structure of ionic liquids immobilized on the magnetic polymer microsphere catalyst, regulating its thickness, and optimizing its structure achieved a catalyst with high activity, excellent stability, and easy magnetic separation.

Tuning CO2 hydrogenation selectivity to obtain targeted value-added chemicals and fuels has attracted great yet everincreasing attention. How ever, a fundamental understanding of the nature to control the selectivity is still lacking, posing a challenge in catalyst design and development. Here, w e report our new discovery in ambient pressure CO2 hydrogenation reaction where selectivity canbe completely reversed by simply changing the crystal phases of TiO2 support (anatase- or rutile-TiO2) or changing metal loadings on anatase-TiO2. Operando spectroscopy and NAP-XPS studies reveal the determining factor is dif ferent electron transfer from metal to support under reaction conditions most probably as a result of the different extents of hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO2 hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design. Fil: Li, Xiaoyu. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Lin, Jian. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Li, Lin. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Huang, Yike. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Pan, Xiaoli. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Collins, Sebastián Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Ren, Yujing. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Su, Yang. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Kang, Leilei. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Liu, Xiaoyan. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Zhou, Yanliang. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Hua. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Aiqin. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Qiao, Botao. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Xiaodong. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Zhang, Tao. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China

Photo-thermo catalysis, which integrates photocatalysis on semiconductors with thermocatalysis on supported nonplasmonic metals, has emerged as an attractive approach to improve catalytic performance. However, an understanding of the mechanisms in operation is missing from both the thermo- and photocatalytic perspectives. Deep insights into photo-thermo catalysis are achieved via the catalytic oxidation of propane (C3 H8 ) over a Pt/TiO2 -WO3 catalyst that severely suffers from oxygen poisoning at high O2 /C3 H8 ratios. After introducing UV/Vis light, the reaction temperature required to achieve 70 % conversion of C3 H8 lowers to a record-breaking 90 °C from 324 °C and the apparent activation energy drops from 130 kJ mol-1 to 11 kJ mol-1 . Furthermore, the reaction order of O2 is -1.4 in dark but reverses to 0.1 under light, thereby suppressing oxygen poisoning of the Pt catalyst. An underlying mechanism is proposed based on direct evidence of the in-situ-captured reaction intermediates.

Strong metal-support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single-atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2 -supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18-electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3-nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI.

Single-atom catalysts (SACs) have attracted extensive attention in the field of heterogeneous catalysis. However, the fabrication of SACs with high loading and high-temperature stability remains a grand challenge, especially on oxide supports. In this work, we have demonstrated that through strong covalent metal-support interaction, high-loading and thermally stable single-atom Pt catalysts can be readily prepared by using Fe modified spinel as support. Better catalytic performance in N2O decomposition reaction is obtained on such SACs than their nanocatalyst counterpart and low-surface-area Fe2O3 supported Pt SACs. This work provides a strategy for the fabrication of high-loading and thermally stable SACs for applications at high temperatures.

Single-atom catalysts (SACs) have demonstrated superior catalytic performance in numerous heterogeneous reactions. However, producing thermally stable SACs, especially in a simple and scalable way, remains a formidable challenge. Here, we report the synthesis of Ru SACs from commercial RuO2 powders by physical mixing of sub-micron RuO2 aggregates with a MgAl1.2Fe0.8O4 spinel. Atomically dispersed Ru is confirmed by aberration-corrected scanning transmission electron microscopy and X-ray absorption spectroscopy. Detailed studies reveal that the dispersion process does not arise from a gas atom trapping mechanism, but rather from anti-Ostwald ripening promoted by a strong covalent metal-support interaction. This synthetic strategy is simple and amenable to the large-scale manufacture of thermally stable SACs for industrial applications., Large scale production of thermally stable single-atom catalysts (SACs) remains challenging. Here, the authors report scalable synthesis of Ru SACs by heating physical mixture of commercial RuO2 and Fe-containing support, which is significantly promoted by strong metal-support interaction.

It remains a substantial challenge to develop a strategy to manipulate the defects of a support which affect the dispersion and morphology and ultimately the catalytic performance of active metals....

Supported gold nanoparticles with sizes below 5 nm display attractive catalytic activities for heterogeneous reactions, particularly those promoted by secondary metal (e.g., Cu) because of the well-defined synergy between metal compositions. However, the specific atomic structure at interfaces is less interpreted systematically. In this work, various bimetallic Au-CuOx catalysts with specific surface structures were synthesized and explored by aberration-corrected scanning transmission electron microscopy (AC-STEM), temperature-programmed experiments and in situ DRIFT experiments. Results suggest that the atomic structure and interfaces between gold and CuOx are determined by the nucleation behaviors of the nanoparticles and result in subsequently the distinctive ability for CO activation. Bimetallic CuO*/Au sample formatted by gold particles surrounded with CuOx nanoclusters have rough surface with prominently exposed low-coordinated Au step defects. Whereas the bimetallic Au@CuO sample formatted by copp...

Cellulosic ethanol is one of the most important biofuels, yet its commercial production is hindered by the low-efficiency and high-cost bioconversion process. Here, we report a new chemocatalytic approach for the one-pot production of cellulosic ethanol. With a multifunctional Mo/Pt/WOx catalyst, cellulose is directly converted to ethanol in a one-pot reaction with a yield as high as 43.2 C%. Kinetic analysis reveals that such a one-pot process involves tandem catalysis from cellulose to ethylene glycol (rapid) followed by hydrogenolysis of ethylene glycol to ethanol (slow). Characterizations show that isolated and low-coordinated MoOx bonds to metallic Pt particles on the mesoporous WOx support, constituting xOMo-PtWOx interfacial sites, which offer high activity for C-O cleavage of ethylene glycol.

Ubiquitin-propargylamide (Ub-PA) is one of the most widely used activity-based probe to measure the activity of deubiquitinases (DUBs) and help validate DUBs targeting inhibitors. However, current synthetic route of Ub-PA is cumbersome. In this work, we report a novel semi-synthetic strategy to prepare Ub-PA in large-scale. Biochemical assays prove that semi-synthetic Ub-PA is an effective probe in identifying DUBs targeting inhibitors.

New synthetic strategies that exploited the strengths of both chemoselective ligation and recombinant protein expression were developed to prepare K27 di-ubiquitins (diUb), which enabled mechanistic studies on the molecular recognition of K27-linked Ubs by single-molecule Förster resonance energy transfer (smFRET) and X-ray crystallography. The results revealed that free K27 diUb adopted a compact conformation, whereas upon binding to UCHL3, K27 diUb was remodeled to an open conformation. The K27 isopeptide bond remained rigidly buried inside the diUb moiety during binding, an interesting unique structural feature that may explain the distinctive biological function of K27 Ub chains.

A novel three-layered catalyst was successfully synthesized by the copolymerization of divinylbenzene and vinyl benzyl chloride in the presence of 3-mercaptopropyltrimethoxysilane-functionalized ma...

The prostate-specific antigen (PSA) is an important biochemical biomarker for the early screening and auxiliary diagnosis of prostate cancer. Hence, developing a simple and rapid method for the sensitive detection of PSA is crucial. Herein, all-in-one signal tags were successfully prepared via a one-pot coprecipitation strategy using ZIF-8 nanoparticles as nanocarriers, methyl yellow (MY) as signal molecules, and the antibodies of PSA as signal recognition units. After treatment with an acid solution, the signal tags (named ZIF-8/MY/Ab2) would hydrolyze and release large amounts of MY molecules to induce an obvious colorimetric signal at 510 nm, which could quantificationally reflect the concentration of PSA. Furthermore, the colorimetric immunosensor exhibited satisfactory specificity, sensitivity, and reproducibility as well as practical feasibility in human serum analysis, which paves a new path for the early diagnosis of prostate cancer.

Recently, CO

Tuning CO

Anti-sintering platinum-based catalyst for propane dehydrogenation (PDH) is promising to avoid corrosive oxychlorination re-dispersion of sintered Pt during coke combustion. Herein, we report an anti-sintering Pt/MgAl2O4 catalyst and optimizations on its activity for PDH with group IB metals (Cu, Ag and Au). Using a suite of characterizations including BET, H2 chemisorption, XRD, STEM, CO-DRIFTs, XANES, XPS, TG/DTA, TPO, C3H6-TPD and TPSR of C3H6 with H2, we reveal that Cu and Ag dilute the surface Pt atoms and donate electron to Pt while the case for Pt-Au is inverse. As a result, significant enhancements in propane conversion and propylene selectivity were obtained on the Pt-Cu/MgAl2O4 and Pt-Ag/MgAl2O4 catalysts. The Pt-Cu/MgAl2O4 exhibited excellent C3H6 yield and regeneration stability, presumably due to the formation of intermetallic compounds and little phase segregation during cyclic dehydrogenation-regeneration runs.

The green synthesis of fine chemicals calls for a new generation of efficient and robust catalysts. Single-atom catalysts (SACs), in which all metal species are atomically dispersed on a solid support, and which often consist of well-defined mononuclear active sites, are expected to bridge homogeneous and heterogeneous catalysts for liquid-phase organic transformations. This review summarizes major advances in the SAC-catalysed green synthesis of fine chemicals in the past several years, with a focus on the catalytic activity, selectivity and reusability of SACs in various organic reactions. The relationship between catalytic performance and the active site structure is discussed in terms of the valence state, coordination environment and anchoring chemistry of single atoms to the support, in an effort to guide the rational design of SACs in this special area, which has traditionally been dominated by homogeneous catalysis. Finally, the challenges remaining in this research area are discussed and possible future research directions are proposed.

Selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) is an important yet challenging method for the transformation of biomass into value-added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found demanding and sensitive to H2 pressure. In this regard, we manipulate the chemical/physical characteristics of the catalyst supports via doping Nb into WOx and prepared 1D needle-, 2D flake-, and 3D sphere-stack mesoporous structured Nb-WOx with increased surface acid sites. Moreover, Nb doping can successfully inhibit the over-reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H2 pressure from 1 to 5 MPa. When Nb doping is 2%, supported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3-PD over an unprecedentedly wide H2 pressure range, which will guarantee better catalyst stability in the long run, as well as expand their applications to other hydrogen-related reactions.