Publications by authors named "Bowen He"

Metal single atoms are of increasing importance in catalytic reactions. However, the mass diffusion is yet substantially limited by the confined surface of the support in comparison to homogeneous catalysis. Here, we demonstrate that cylindrical micellar brushes with highly solvated poly(2-vinylpyridine) coronas can immobilize 33 types of metal single atoms with 8.

View Article and Find Full Text PDF

A novel dual photoredox/copper-catalyzed three-component alkylcyanation of alkenes and 1,4-alkylcyanation of 1,3-enynes have been developed. In this radical cyanoalkylation reaction, the photoredox induced alkyl radical from sulfoxonium ylides adds to the carbon-carbon double bonds of styrenes or 1,3-enynes, and the generated benzylic or allenyl radicals couple with a Cu(II) cyanide complex to achieve selective cyanation. The reaction exhibits high chemo- and regioselectivity and a wide substrate scope, providing an efficient method for the synthesis of alkyl nitriles and allenyl nitriles in a single step.

View Article and Find Full Text PDF

Catalytic activity of metal particles is reported to originate from the appearance of nonmetallic states, but conductive metallic particles, as an electron reservoir, should render electron delivery between reactants more favorably so as to have higher activity. We present that metallic rhodium particle catalysts are highly active in the low-temperature oxidation of carbon monoxide, whereas nonmetallic rhodium clusters or monoatoms on alumina remain catalytically inert. Experimental and theoretical results evidence the presence of electronic communications in between vertex atom active sites of individual metallic particles in the reaction.

View Article and Find Full Text PDF

Propane dehydrogenation (PDH) is crucial for propylene production, but commercially employed Pt-based catalysts face susceptibility to deactivation due to the Pt sintering during reaction and regeneration steps. Here, we report a SiO supported nanometric (MnCoCuZnPt) high-entropy PDH catalyst with high activity and stability. The catalyst exhibited a super high propane conversion of 56.

View Article and Find Full Text PDF

Investigating the effects of spatial scales on the uncertainty and sensitivity analysis of the social vulnerability index (SoVI) model output is critical, especially for spatial scales finer than the census block group or census block. This study applied the intelligent dasymetric mapping approach to spatially disaggregate the census tract scale SoVI model into a 300-m grids resolution SoVI map in Davidson County, Nashville. Then, uncertainty analysis and variance-based global sensitivity analysis were conducted on two scales of SoVI models: (a) census tract scale; (b) 300-m grids scale.

View Article and Find Full Text PDF

Magnetic nanocatalysts with properties of easy recovery, induced heating, or magnetic levitation play a crucial role in advancing intelligent techniques. Herein, we report a method for the synthesis of versatile core-shell-type magnetic nanocatalysts through "noncontact" hydrogen spillover-driven reduction and migration of iron oxide with the assistance of Pd. analysis techniques were applied to visualize the dynamic evolution of the magnetic nanocatalysts.

View Article and Find Full Text PDF

The synthesis of highly dispersed Au nanoclusters that are stable under elevated temperatures in heterogeneous catalysis is challenging. Here, we directly observe a strong metal-support interaction (SMSI)-induced dispersion of Au nanoparticles (NPs) on α-MoC using an environmentally atomically resolved secondary imaging technique. Under a realistic environment, Au NPs flatten and spread out on the α-MoC to form two-dimensional atomic layered clusters.

View Article and Find Full Text PDF

Cooperative coupling of H evolution with oxidative organic synthesis is promising in avoiding the use of sacrificial agents and producing hydrogen energy with value-added chemicals simultaneously. Nonetheless, the photocatalytic activity is obstructed by sluggish electron-hole separation and limited redox potentials. Herein, Ni-doped Zn Cd S quantum dots are chosen after screening by DFT simulation to couple with TiO microspheres, forming a step-scheme heterojunction.

View Article and Find Full Text PDF
Article Synopsis
  • Aeolian sand (AS) and recycled coarse aggregate (RCA) are proposed as eco-friendly alternatives to natural sand and gravel for enhancing concrete, addressing shortages and promoting environmental sustainability.
  • The study examines the effects of freeze-thaw cycles on self-compacting concrete containing varying percentages of AS and RCA, analyzing damage through methods like mass loss and elasticity modulus.
  • Findings suggest that incorporating 20-40% AS and 25-50% RCA reduces freeze-thaw damage, and a predictive damage model based on Weibull distribution aligns well with experimental results.
View Article and Find Full Text PDF

In this study, a dual-mode ratiometric fluorometric and colorimetric platform for the determination of nitrite in pickles was proposed by exquisitely employing the fact that non-fluorescent o-Phenylenediamine (OPD) was oxidized by nitrite under acidic conditions to form fluorescent 2,3-diaminophenazine (DAP) (Em = 575), which meanwhile quench the fluorescent nitrogen-doped carbon dots (N-CDs) at 455 nm, the ratio of fluorescence intensity of DAP to N-CDs (F/F) changed with the increase of nitrite accompanied by visible color changes. Thus, nitrite can be quantitatively detected within a wide linear range (10-500 µM) with a low detection limit of 0.45 µM due to the high quantum yield of 39.

View Article and Find Full Text PDF

Gallic acid (GA, 3,4,5-trihydroxybenzoic acid) is a widely used natural food additive of interest to food chemistry researchers, especially regarding its effects on myofibrillar protein (MP) oxidation. However, existing studies regarding MP oxidation by GA-combined with Fenton reagents are inconsistent, and the detailed mechanisms have not been fully elucidated. This work validated hydroxyl radical (HO) as the primary oxidant for MP carbonylation; in addition, it revealed three functions of GA in the Fenton oxidation of MP.

View Article and Find Full Text PDF

Background: Ossification of ligamentum flavum (OLF) is a hidden, indolent disease condition with variable unexplained etiology and pathology. Growing evidences show a correlation between senile osteoporosis (SOP) and OLF, but the fundamental relationship between SOP and OLF remains unclear. Therefore, the purpose of this work is to investigate unique SOP-related genes and their potential functions in OLF.

View Article and Find Full Text PDF
Article Synopsis
  • This text discusses the development of a novel nanocatalyst that combines various functions, such as catalysis and microenvironment heating, into a single structure.
  • This catalyst enables selective hydrogenation of unsaturated aldehydes/ketones to alcohols at low temperatures (40 °C) and moderate pressure (3 bar), achieving over 98% selectivity, in contrast to traditional methods that require harsher conditions.
  • The design improves reaction kinetics through localized increases in temperature and pressure in a nano-sized space, allowing for stable product formation and reduced over-hydrogenation risks.
View Article and Find Full Text PDF

A Gram-stain-negative marine bacterium, designated as WX04, was isolated from the South China Sea. The genome of strain WX04 contained a complete photosynthetic gene cluster and is the first identified photoheterotroph of the genus with high photochemical efficiency (Fv/Fm=0.705±0.

View Article and Find Full Text PDF

In the templated synthesis of colloidal core-shell nanoparticles, the monomer attachment growth mechanism has been widely accepted to describe the growth process of shells. In this work, by using advanced transmission electron microscope techniques, we directly observe two alternative particle attachment growth pathways that dominate the growth of Au@Ag core-shell nanocuboids. One pathway involves the reduction of AgCl nanoparticles attached to Au nanorods and the subsequent epitaxial growth of the Ag shell.

View Article and Find Full Text PDF

Chemical electron microscopy (CEM), a toolbox that comprises imaging and spectroscopy techniques, provides dynamic morphological, structural, chemical, and electronic information about an object in chemical environment under conditions of observable performance. CEM has experienced a revolutionary improvement in the past years and is becoming an effective characterization method for revealing the mechanism of chemical reactions, such as catalysis. Here, we mainly address the concept of CEM for heterogeneous catalysis in the gas phase and what CEM could uniquely contribute to catalysis, and illustrate what we can know better with CEM and the challenges and future development of CEM.

View Article and Find Full Text PDF

Precise synthesis of well-ordered ultrathin nanowire arrays with tunable active surface, though attractive in optoelectronics, remains challenging to date. Herein, well-aligned sub-10 nm TiO nanowire arrays with controllable corrugated structure have been synthesized by a unique monomicelle-directed assembly method. The nanowires with an exceptionally small diameter of ∼8 nm abreast grow with an identical adjacent distance of ∼10 nm, forming vertically aligned arrays (∼800 nm thickness) with a large surface area of ∼102 m g.

View Article and Find Full Text PDF

Cooperative coupling of photocatalytic H O production with organic synthesis has an expansive perspective in converting solar energy into storable chemical energy. However, traditional powder photocatalysts suffer from severe agglomeration, limited light absorption, poor gas reactant accessibility, and reusable difficulty, which greatly hinders their large-scale application. Herein, floatable composite photocatalysts are synthesized by immobilizing hydrophobic TiO and Bi O on lightweight polystyrene (PS) spheres via hydrothermal and photodeposition methods.

View Article and Find Full Text PDF

High-entropy alloys (HEAs) with multiple elements in near-equiatomic proportions hold great promise in heterogeneous catalysis because of their exceptional physicochemical properties governed by synergy. Herein, we prepared PtPdCoCuNi HEA nanoparticles a one-step colloid-based route and tested their catalytic performance for nitrobenzene hydrogenation to aniline. The SiO supported PtPdCoCuNi displays 93.

View Article and Find Full Text PDF

Tailoring the morphology of nanocrystals is a promising way to enhance their catalytic performance. In most previous shape-controlled synthesis strategies, surfactants are inevitable due to their capability to stabilize different facets. However, the adsorbed surfactants block the intrinsic active sites of the nanocrystals, reducing their catalytic performance.

View Article and Find Full Text PDF

Ammonia and nitrates are the most fundamental and significant raw ingredients in human society. Till now, industrial synthetic ammonia by Haber-Bosch process and industrial synthetic nitrates by the Ostwald process have encountered increasingly serious challenges, i.e.

View Article and Find Full Text PDF

In order to study the seasonal variations and pollution sources of carbonaceous species in PM in Chengde, the concentration of these components was determined in atmospheric PM samples collected in January, April, July, and October 2019. The change in carbonaceous species were analyzed based on the estimation of the ratio of organic carbon(OC) to elemental carbon(EC), total carbonaceous aerosol(TCA), and secondary organic carbon(SOC). The source of these pollutants was determined by means of the backward trajectory and principal component analysis(PCA).

View Article and Find Full Text PDF

In order to systematically study the transmission characteristics of seasonal and typical pollutants in Shijiazhuang, hourly data of ground-level pollutants(PM, PM, O, NO, SO, and CO) from 46 state-and provincial-controlled stations, and meteorological(temperature, humidity, and wind speed) data from 17 counties in Shijiazhuang City from December 2018 to November 2019 was analyzed. The interpolation(IDW) and correlation analysis were applied to seasonal and temporal spatial patterns of pollutant concentration. The backward trajectories analysis was performed to explore the seasonal transmission pattern and potential source areas of pollution in Shijiazhuang by combining with the global data assimilation system(GDAS).

View Article and Find Full Text PDF

Fluorescent whitening agents (FWAs) are very important chemical additives that are widely applied in the industrial production field. The history of global FWA production and use spans more than 60 years, but the environmental fate of FWAs has been less reported in the public literature and most studies predate 2000; in addition, the studied FWAs were still limited to FWA71 and FWA351. In this study, the occurrence and distribution of 9 commonly used FWAs in a lake in North China were reported for the first time.

View Article and Find Full Text PDF