Fabrication of Nickel Single Atoms with Ionic Liquids by Only One-Step Pyrolysis for CO2 Electroreduction.

Single-atom catalysts (SACs) are appealing for carbon dioxide (CO2) electroreduction with the utmost advantages; however, their preparation is still challenging because of the complicated procedure. Here, a novel Ni-based single-atom catalyst (Ni-BB-BD) is constructed from raw materials, [BMIM]BF4, [BMIM]DCN, and NiCl2·6H2O, directly without any precursor by only one-step pyrolysis. Ni-BB-BD achieves a maximum carbon monoxide Faradaic efficiency (FECO) of 96.5% at -0.8 V vs RHE, as well as long-term stability over 16 h. High current density up to -170.6 mA cm-2 at -1.0 V vs RHE is achieved in the flow cell along with a CO selectivity of 97.7%. It is identified that [BMIM]BF4 is the nitrogen source, while [BMIM]DCN is mainly taken as the carbon source. Theoretical studies have revealed that the rich nitrogen content, especially for the uncoordinated nitrogen, plays a critical role in lowering rate-limiting barrier height. This work develops a facile and effective strategy to prepare the SACs.

N/O Co-doped hierarchical nanoporous biochar derived from waste polypropylene nonwoven for high-performance supercapacitors.

How to efficiently treat municipal solid waste (MSW) has become one of the critical solutions in response to the call for "carbon neutrality". Here, the waste polypropylene nonwoven fabric of waste diapers was converted into hierarchical nanoporous biochar (HPBC) through pre-carbonization and activation processes as an ideal precursor for supercapacitors (SCs) with excellent performance. The prepared HPBC-750-4 with an ultrahigh specific surface area (3838.04 m2 g-1) and abundant heteroatomic oxygen (13.25%) and nitrogen (1.16%) codoped porous biochar structure. Given its structural advantages, HPBC-750-4 achieved a specific capacitance of 340.9 F g-1 at a current density of 1 A g-1 in a three-electrode system. Its capacitance retention rate was above 99.2% after 10 000 cycles at a current density of 10 A g-1, which indicated an excellent rate capability and long-term cycling stability. Furthermore, the HPBC-750-4//HPBC-750-4 symmetric SC exhibited a superb energy density of 10.02 W h kg-1 with a power density of 96.15 W kg-1 in a 6 M KOH electrolyte. This work not only demonstrates the enormous potential of waste polypropylene nonwoven fabric in the SC industry but also provides an economically feasible means of managing MSW.

In Situ Synergistic Catalysis Hydrothermal Liquefaction of Spirulina by CuO-CeO2 and Ni-Co to Improve Bio-oil Production.

Hydrothermal liquefaction (HTL) is one of the most promising technologies for biofuel production. The preparation and application of catalysts for HTL have been the research focus in recent years. In this study, a new synergistic catalytic process strategy is proposed. CuO-CeO2/γ-Al2O3 was used as an in situ hydrogen donor catalyst and Ni-Co/SAPO-34 was synthesized for hydroprocessing to improve bio-oil production process. The results of XRD and XPS demonstrated that the metal components were well supported on the catalyst. When the two catalysts were mixed, the yield of bio-oil increased from 51.00% to 64.51%, the carbon recovery rate raised from 69.53% to 88.18%, the energy recovery rate grew from 63.42% to 80.22%, and the S content is relatively reduced by 83.3%. Also, TG analysis showed that the content of light components in bio-oil increased. Moreover, the hydrocarbons and alcohols were observed to a higher proportion from the GC-MS analysis. This new method still has high catalytic activity after repeated use for five times. This study provides a new idea for preparing higher yield and superior quality bio-oil.

[Effect of Cu-Ce/γ-Al2O3 catalyst on bio-oil production by hydrothermal deoxygenation of stearic acid].

In order to improve the hydrothermal deoxygenation of organic acids as well as to reduce the cost, we prepared a Cu-Ce/γ-Al2O3 catalyst to study the hydrothermal deoxygenation of stearic acid in the absence of H2. The Brunauer-Emmett-Teller surface area and X-ray diffraction pattern suggest that both CuO and CeO2 exist in the Cu-Ce/γ-Al2O3 catalyst. The crystals of Cu-Ce/γ-Al2O3 were more stable compared with those of the Cu/γ-Al2O3 catalyst after 12 h of hydrothermal liquefaction at 300℃, thereby indicating a better thermal stability of the former. The presence of Cu-Ce/γ-Al2O3 catalyst could greatly improve the conversion of stearic acid (94.71%) and the yield of hydrocarbon (81.41%). A preliminary analysis of the mechanism suggests that decarboxylation is the main step in the deoxygenation during the hydrothermal liquefaction of stearic acid. The addition of Cu/γ-Al2O3 and Cu-Ce/γ-Al2O3 decreased the yield of n-heptadecane and increased the yield of n-octadecane. Besides, the yields of n-paraffins increased drastically from 0.45% to 49.72% along the series from n-nonane to n-hexadecane. Thus, the cracking reactions could be improved in the presence of Cu-Ce/γ-Al2O3, suggesting that it is an efficient deoxygenation catalyst in the hydrothermal liquefaction of organic acid. In addition, the Cu-Ce/γ-Al2O3 catalyst could help in removing the carbonyl groups, and this effectively reduced the amounts of aldehydes and ketones in the bio-oil.

Molecular dynamics simulation of temperature induced unfolding of animal prion protein.

To elucidate the structural stability and the unfolding dynamics of the animal prion protein, the temperature induced structural evolution of turtle prion protein (tPrPc) and bank vole prion protein (bvPrPc) have been performed with molecular dynamics (MD) simulation. The unfolding behaviors of secondary structures showed that the α-helix was more stable than ß-sheet. Extension and disruption of ß-sheet commonly appeared in the temperature induced unfolding process. The conversion of α-helix to π-helix occurred more readily at the elevating temperature. Furthermore, it was suggested in this work that the unfolding of prion protein could be regulated by the temperature.