This study has designed and implemented a library of hetero‐nanostructured catalysts, denoted as Pd@Nb2O5, comprised of size‐controlled Pd nanocrystals interfaced with Nb2O5 nanorods. This study also demonstrates that the catalytic activity and selectivity of CO2 reduction to CO and CH4 products can be systematically tailored by varying the size of the Pd nanocrystals supported on the Nb2O5 nanorods. Using large Pd nanocrystals, this study achieves CO and CH4 production rates as high as 0.75 and 0.11 mol h−1 gPd −1, respectively. By contrast, using small Pd nanocrystals, a CO production rate surpassing 18.8 mol h−1 gPd −1 is observed with 99.5% CO selectivity. These performance metrics establish a new milestone in the champion league of catalytic nanomaterials that can enable solar‐powered gas‐phase heterogeneous CO2 reduction. The remarkable control over the catalytic performance of Pd@Nb2O5 is demonstrated to stem from a combination of photothermal, electronic and size effects, which is rationally tunable through nanochemistry.

Urea, an agricultural fertilizer, nourishes humanity. The century‐old Bosch–Meiser process provides the world's urea. It is multi‐step, consumes enormous amounts of non‐renewable energy, and has a large CO2 footprint. Thus, developing an eco‐friendly synthesis for urea is a priority. Herein we report a single‐step Pd/LTA‐3A catalyzed synthesis of urea from CO2 and NH3 under ambient conditions powered solely by solar energy. Pd nanoparticles serve the dual function of catalyzing the dissociation of NH3 and providing the photothermal driving force for urea formation, while the absorption capacity of LTA‐3A removes by‐product H2O to shift the equilibrium towards urea production. The solar urea conversion rate from NH3 and CO2 is 87 μmol g−1 h−1. This advance represents a first step towards the use of solar energy in urea production. It provides insights into green fertilizer production, and inspires the vision of sustainable, modular plants for distributed production of urea on farms.

Urea, an agricultural fertilizer, nourishes humanity. The century-old Bosch-Meiser process provides the worlds urea. It is multi-step, consumes enormous amounts of nonrenewable energy, and has a large CO 2 footprint. Thus, developing an eco-friendly synthesis for urea is a priority. Herein we report a single-step Pd/LTA-3A catalyzed synthesis of urea from CO 2 and NH 3 under ambient conditions powered solely by solar energy. Pd nanoparticles serve the dual function of catalyzing the dissociation of NH 3 and providing the photothermal driving force for urea formation, while the absorption capacity of LTA-3A removes by-product H 2 O to shift the equilibrium towards urea production. The solar urea conversion rate from NH 3 and CO 2 is 87 mmol g À1 h À1 . This advance represents a first step towards the use of solar energy in urea production. It provides insights into green fertilizer production, and inspires the vision of sustainable, modular plants for distributed production of urea on farms.Humans and animals excrete excess nitrogen in the form of urea. Historically, urea was the first naturally occurring organic compound to be synthesized by Friedrich Wçhler in 1828. Surprisingly at the time, he made all-organic urea by a thermally induced reconstruction of an all-inorganic compound, ammonium cyanate, connecting the fields of organic and inorganic chemistry.

Since the COVID-19 pandemic is expected to become endemic, quantification of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in ambient waters is critical for environmental surveillance and for early detection of outbreaks. Herein, we report the development of a membrane-based in-gel loop-mediated isothermal amplification (mgLAMP) system that is designed for the rapid point-of-use quantification of SARS-CoV-2 particles in environmental waters. The mgLAMP system integrates the viral concentration, in-assay viral lysis, and on-membrane hydrogel-based RT-LAMP quantification using enhanced fluorescence detection with a target-specific probe. With a sample-to-result time of less than 1 h, mgLAMP successfully detected SARS-CoV-2 below 0.96 copies/mL in Milli-Q water. In surface water, the lowest detected SARS-CoV-2 concentration was 93 copies/mL for mgLAMP, while the reverse transcription quantitative polymerase chain reaction (RT-qPCR) with optimal pretreatment was inhibited at 930 copies/mL. A 3D-printed portable device is designed to integrate heated incubation and fluorescence illumination for the simultaneous analysis of nine mgLAMP assays. Smartphone-based imaging and machine learning-based image processing are used for the interpretation of results. In this report, we demonstrate that mgLAMP is a promising method for large-scale environmental surveillance of SARS-CoV-2 without the need for specialized equipment, highly trained personnel, and labor-intensive procedures.

In the aqueous environment, Fe II ions enhance the oxidative potential of ozone and hydrogen peroxide by generating the reactive oxoiron species (ferryl ion, Fe IV O 2+ ) and hydroxyl radical (•OH) via Fenton chemistry. Herein, we investigate factors that control the pathways of these reactive intermediates in the oxidation of dimethyl sulfoxide (Me 2 SO) in Fe II solutions reacting with O 3 in both bulk-phase water and on the surfaces of aqueous microdroplets. Electrospray ionization mass spectrometry is used to quantify the formation of dimethyl sulfone (Me 2 SO 2 , from Fe IV O 2+ + Me 2 SO) and methanesulfonate (MeSO 3 − , from •OH + Me 2 SO) over a wide range of Fe II and O 3 concentrations and pH. In addition, the role of environmentally relevant organic ligands on the reaction kinetics was also explored. The experimental results show that Fenton chemistry proceeds at a rate ∼10 4 times faster on microdroplets than that in bulk-phase water. Since the production of MeSO 3 − is initiated by •OH radicals at diffusion-controlled rates, experimental ratios of Me 2 SO 2 /MeSO 3 − > 10 2 suggest that Fe IV O 2+ is the dominant intermediate under all conditions. Me 2 SO 2 yields in the presence of ligands, L, vary as volcanoplot functions of E 0 (LFe IV O 2+ + O 2 /LFe 2+ + O 3 ) reduction potentials calculated by DFT with a maximum achieved in the case of L≡oxalate. Our findings underscore the key role of ferryl Fe IV O 2+ intermediates in Fenton chemistry taking place on aqueous microdroplets.

The size dependence of the photothermal effect of palladium nanocrystals enables the selectivity of the solar powered heterogeneous catalytic hydrogenation of carbon dioxide to be finely tailored towards producing either carbon monoxide through the reverse water gas shift reaction, CO 2 + H 2 → CO + H 2 O, favored for small nanocrystals or to methane, via the Sabatier methanation reaction, CO 2 + 4H 2 → CH 4 + 2H 2 O, preferred for larger nanocrystals. This is described by Geoffrey A. Ozin and co‐workers in article number 1700252 .

Droplets during human speech are found to remain suspended in the air for minutes, while studies suggest that the SARS-CoV-2 virus are infectious in experimentally produced aerosols for more than...

Deposition is a major route for atmospheric pollutants such as heavy metals and polycyclic aromatic hydrocarbons (PAHs) to transport to surface water. Here, we study Beijing, China, during the heavy haze period (2014) and the pandemic period (2021) to investigate the correlation between the atmospheric and surface water concentrations of 12 heavy metals and 16 PAHs. Pearson correlations and a series of back propagation (BP) neural network (NN) models are employed, and local meteorological conditions are included as input variables for the analysis. The surface water concentration of most pollutants analyzed correlate positively with humidity, PM2.5, PM10, NO2, SO2, and CO, while negatively with the wind speed. The correlation coefficients are bigger in 2014 than in 2021, indicating accelerated gas–aqueous mass transport during haze episodes. The accurate prediction of the BP NN model in 2014 and 2021 presents itself as a promising tool in guiding future modeling efforts and policy changes.