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The development of new type electrocatalysts with promising activity and antipoisoning ability is of great importance for electrocatalysis on alcohol oxidation. In this work, Pd nanowire (PdNW)/CuO x heterogeneous catalysts with different types of PdOCu interfaces (Pd/amorphous or crystalline CuO x ) are prepared via a two-step hydrothermal strategy followed by an air plasma treatment. Their interface-dependent performance on methanol and ethanol oxidation reaction (MOR and EOR) is clearly observed. The asprepared PdNW/crystalline CuO x catalyst with 17.2 at% of Cu on the PdNW surface exhibits better MOR and EOR activity and stability, compared with that of PdNW/amorphous CuO x and pristine PdNW catalysts. Significantly, both the cycling tests and the chronoamperometric measurements reveal that the PdNW/crystalline CuO x catalyst yields excellent tolerance toward the possible intermediates including formaldehyde, formic acid, potassium carbonate, and carbon monoxide generated during the MOR process. The detailed analysis of their chemical state reveals that the enhanced activity and antipoison ability of the PdNW/crystalline CuO x catalyst originates from the electron-deficient Pd δ+ active sites which gradually turn into Pd 5 O 4 species during the MOR catalysis. The Pd 5 O 4 species can likely be stabilized by moderate crystalline CuO x decorated on the surface of PdNW due to the strong PdOCu interaction. www.advancedsciencenews.com

This paper demonstrates a one-pot approach to produce highly dispersed dendritic palladium-platinum bimetallic nanoparticles (NPs) with small particle size, tunable composition and high catalytic activity. Herein, the PdPt bimetallic NPs have been obtained using bayberry tannin (BT) as both the reducing agent and surfactant. Additionally, the PdPt bimetallic NPs with different Pd/Pt atomic ratios can be prepared by just varying the amounts of the Pd and Pt precursors. Most importantly, the as-prepared Pd 52 Pt 48 catalyst exhibits the optimal catalytic activities compared with the other compositional PdPt NPs (Pd 82 Pt 18 , Pd 69 Pt 31 , and Pd 36 Pt 64 ) and commercial Pt/C (20 wt.%) catalyst for the methanol oxidation reaction (MOR). Meanwhile, Pd 52 Pt 48 also shows better CO tolerance, which can be attributed to the unique dendritic structure and the synergistic effect between Pd and Pt. With evident advantages of the facile preparation and enhanced catalytic performance, it holds great promise as a high-performance catalyst for electrochemical energy conversion.

Polycyclic aromatic hydrocarbon (PAH) emissions from the combustion of household solid coal for cooking and heating cause great harm to public health in China, especially in less developed areas. Children are one of the most susceptible population groups at risk of indoor air pollutants due to their immature respiratory and immune systems. However, information on PAH exposure of children is limited due to limited monitoring data. In this study, we aimed to assess the seasonal differences of PAHs in classrooms, analyze the pollutant sources, and calculate the incremental lifetime cancer risk attributable to PAHs in Shanxi Provence. A typical school using household coal combustion in Shanxi Province was selected. Fine particulate matter (PM2.5)samples were collected by both individual samplers and fixed middle-flow samplers during the heating and non-heating seasons in December 2018 and April 2019. The PAH concentrations in PM2.5 samples were analyzed by a gas chromatograph coupled to a mass spectrometer. The results showed that PAH concentrations in PM2.5 varied between 89.1 ng/m3 in the heating season and 1.75 ng/m3 in the non-heating season. The mean concentrations of benzo[a]pyrene (BaP), a carcinogenic marker of PAHs, were 10.3 and 0.05 ng/m3 in the heating and non-heating seasons, respectively. Source allocation analysis of individual portable and passive samplers revealed that the main contributors during heating and non-heating seasons were coal combustion and gasoline sources, respectively. According to the results of a Monte Carlo simulation, the incremental lifetime cancer risk values from the inhalation of PAHs in the heating and non-heating seasons were 3.1 × 10−6 and 5.7 × 10−8, respectively. The significant increase in PAHs and the incremental lifetime cancer risk in the heating season indicates that children are more exposed to health threats in winter. Further PAH exposure control strategies, including reducing coal usage and promoting clean fuel applications, need to be developed to reduce the risk of PAH-induced cancer.

Pt-based catalysts for methanol fuel electrooxidation typically suffer from CO intermediate poisoning. Herein, we incorporated secondary Ni element into PtPd hollow nanocrystals (HNCs) to fabricate a trimetallic NiPtPd-HNCs catalyst with superior CO tolerance and high activity for methanol electro-oxidation. The as-prepared trimetallic NiPtPd-HNCs exhibit promising specific and mass activity of 10.68 mA•cm −2 and 3.95 A•mg Pd+Pt −1, respectively, which is 4.2and 4.5-fold higher than that of commercial Pt/C. Notably, CO-stripping tests and 3000 s chronoamperometry experiments in a rigorous CO-saturated medium show that trimetallic NiPtPd-HNCs possess higher CO tolerance compared with that of the bimetallic counterparts. Ultimately, we ascribed to the enhanced activity and CO tolerance of trimetallic NiPtPd-HNCs to (i) the preponderance of hollow interior and dendritic morphology, (ii) the considerably improved binding energy of OH ads on NiPtPd surface which is beneficial to the removal of the partial oxidation intermediates during the methanol electrooxidation, and (iii) the modification of the electronic structure of Pt and Pd caused by Ni heteroatoms exposure to surface. The employment of Ni may be extended to the rational development of other Pt-based multimetallic nanocrystals with high CO tolerance and promising activity in the small molecules fuel electro-oxidation.