Liquid phase oxidation of cyclohexane was carried out over copper pyrophosphate catalyst using hydrogen peroxide as an oxidant in CH
3CN at the temperature between 25 and 80
°C. It was found that ...appropriate surface hydrophobicity is the key factor for the excellent performance of the catalyst. Additionally, a significant improvement for the cyclohexane conversion in the presence of organic acid was observed.
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Liquid phase oxidation of cyclohexane was carried out under mild reaction condition over copper pyrophosphate catalyst in CH
3CN using hydrogen peroxide as an oxidant at the temperature between 25 and 80
°C. The copper pyrophosphate catalyst was characterized by means of XRD, FT-IR and water contact angle measurement. It was found that appropriate surface hydrophobicity is the key factor for the excellent performance of the catalyst. In addition, a significant improvement for the cyclohexane conversion in the presence of organic acid was observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•CuSe-Co3Se4@VSe2 nanotube clusters were synthesized by a facile template method.•CuSe-Co3Se4@VSe2 was used as a bifunctional catalyst for HER and DSSCs.•CuSe-Co3Se4@VSe2 had lower ...overpotential for basic HER (76 mV@10 mA cm−2).•The PCE (9.64%) of CuSe-Co3Se4@VSe2 was much higher than that of Pt (8.39%).
Among the various non-precious metal catalysts that drive hydrogen evolution reactions (HERs) and dye-sensitized solar cells (DSSCs), transition metal selenides (TMSs) stand out due to their unique electronic properties and tunable morphology. Herein, the multicomponent selenide CuSe-Co3Se4@VSe2 was successfully synthesized by doping with metal element vanadium and selenization on the copper-cobalt carbonate hydroxide (CuCo-CH) template. CuSe-Co3Se4@VSe2 exhibited the dandelion-like cluster structure composed of hollow nanotubes doped with VSe2 nanoparticles. Due to the unique structure and the synergistic effect of various elements, CuSe-Co3Se4@VSe2 showed excellent alkaline HER and DSSC performances. The DSSC based on CuSe-Co3Se4@VSe2 exhibited an impressive power conversion efficiency (PCE) of 9.64 %, which was much higher than that of Pt (8.39 %). Besides, it possessed a low HER overpotential of 76 mV@10 mA cm−2 and a small Tafel slope of 88.9 mV dec−1 in 1.0 M KOH.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
At present, the exploration of renewable energy is a huge challenge, and water electrolysis is regarded as a promising method for producing hydrogen. However, the hydrogen evolution reaction (HER) ...has been hampered due to expensive Pt-based catalysts. Herein, the Fe2P-coated Ni2P/Co2P nanospheres with yolk-shelled structure were successfully synthesized according to a facile approach of doping transition metal elements and phosphating on the template Ni-Co nanospheres, successively. All samples were tested as HER catalysts at various pH environments. The results showed that the Fe2P-Ni2P/Co2P possesses superior electrocatalytic ability and good stability. The Fe2P-Ni2P/Co2P achieved the lower ηonset (overpotential at 1.0 mA cm−2) of 36.6, 64.2, and 65.9 mV, η10 (overpotential at 10 mA cm−2) of 89.7, 125, and 212 mV, and Tafel slopes of 48.0, 60.3, and 135 mV dec−1 in acidic, alkaline, and neutral solutions, respectively, exhibiting an excellent electrocatalytic activity of the multicomponent phosphides for HER.
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•Yolk-shelled nanospheres Fe2P-Ni2P/Co2P was synthesized by a template method.•The synergistic effect was used to improve the electrocatalytic performance.•Fe2P-Ni2P/Co2P had large surface area and high catalytic activity for HER.•Fe2P-Ni2P/Co2P had satisfactory HER performance over a wide pH range.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Due to its excellent electrochemical performance, O3-type NaNi
0.33
Fe
0.33
Mn
0.33
O
2
(NFM) is one of the most promising cathode materials for sodium ion. However, its poor air stability has ...limited the industrialization process. In this work, a low-temperature two-step method which included carbon doping and acid treatment was used to improve the electrochemical property of the air-aged NaNi
0.33
Fe
0.33
Mn
0.33
O
2.
X-ray diffraction results indicated that the structure of modified NFM (NFM-M) has good crystal structure stability. NFM-M, NFM-48H (NFM after air ageing of 48 h) and fresh NFM possessed a discharge capacity of 95.25, 74.92, and 100.79 mAh·g
−1
in the first cycle, respectively. The modified sample exhibits outstanding cycling stability, with a capacity retention of 90.15% after 100 cycles at 0.1 C rate. Moreover, the NFM-M sample delivers excellent rate capability with improved capacity retention of 66.9% at 2.0 C rate.
Magnesium-based materials are favored by researchers because of their high hydrogen storage capacity, but they cannot be put to daily use because of their more demanding reaction conditions. ...Recently, the method to improve the hydrogen storage performance of MgH2 by catalyst doping has been widely investigated. In this paper, Co3O4 catalysts were prepared by homogeneous precipitation method. It was demonstrated that the Co3O4 catalyst could effectively improve the hydrogen storage performance of MgH2. According to the experimental results, the dehydrogenation onset temperature of the MgH2+15 wt% Co3O4 composite was about 200 °C, which was about 130 °C lower than that of pure MgH2, and the amount of dehydrogenation was 6.26 wt%. The dehydrogenation activation energy of the MgH2+15 wt% Co3O4 composite was reduced to 89.13 kJ/mol, which was about 45.7% lower than that of pure MgH2. After complete dehydrogenation, the composites started to absorb hydrogen at 50 °C with 6.2 wt%, while the activation energy of reabsorption was also reduced to 47.97 kJ/mol. After 10 cycles of MgH2+15 wt% Co3O4 composites, the hydrogen storage capacity of MgH2 could still be maintained at 99%, which indicated that it had good cycling stability. It was confirmed by various characterizations that Co3O4 was uniformly distributed on the MgH2 matrix after ball milling. After the first reaction, Co3O4 was converted to CoO, which was uniformly attached to the Mg/MgH2 surface and stabilized during the cycling process, continuing to provide active sites for hydrogen.
The hydrogen storage composite MgH2+Co3O4 was prepared in this study, and Co3O4 was uniformly distributed on the MgH2 matrix. In the first hydrogen release process, Co3O4 is gradually converted to CoO, and then in the hydrogen absorption process, hydrogen enters Mg. During the cycle, the CoO is in a stable state and evenly dispersed on the Mg/MgH2 surface, continuing to provide an active site for hydrogen. Display omitted
•Co3O4 with good air adaptation performance is applied to MgH2 system.•Composites started to release H2 at 200 °C and could start to absorb H2 at 50 °C.•The activation energy of de/hydrogenation was significantly reduced for composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Co-upgrading of biomass and plastic vapors was conducted by zeolites coupled with NTP.•The synergy of Ru, Ti species and NTP enhanced formation of active atomic radicals.•Integration of mixed ...volatiles was strengthened to lower oxygen and increase yield.•TiHZ5 gave the maximum MAHs selectivity (64.19 %) and minimum PAHs selectivity (7.95 %).•Metal modified HZSM-5 induced by NTP had high coke-resistance and removed coke easily.
Co-upgrading of biomass and polyethylene -derived volatiles was conducted over HZSM-5 and its metal-modified versions, and NTP was introduced to enhance the conversion. The effects of metal species on the active radicals, organic yields, properties and compositions were explored. The Ru and Ti species, especially the low-valence titanium-oxides, increased atomic radicals, relieved the bottleneck of hydrogen transfer, and induced more volatiles into the radicals scale. The synergy of acid sites, metal species and NTP contributed to the integration of volatiles and exhibited promising potential in lowering oxygen and increasing organic yield. Specifically, TiHZ5 yielded the organic liquid of 58.73 % with the HHV of 38.73 MJ/kg, and RuHZ5 produced 51.70 % of organic liquid with the HHV of 36.96 MJ/kg. The synergy between SnHZ5 and NTP was so weak that it sacrificed partial yield to promote HHV. The Ru, Ti, and Sn modification increased the aromatic selectivity from 23.38 %–48.9 %, 72.14 % and 35.66 %, respectively, which caused the decrease of effective hydrogen to carbon ratios. Particularly, TiHZ5 gave the maximum MAHs selectivity of 64.19 % and minimum PAHs selectivity of 7.95 %. Besides, Ru, Ti and Sn modification decreased coking rate from 16.97 % to 7.04 %, 4.62 % and 8.46 %, respectively, and removal of coke became easier. This study provided a new waste-energy refinery way to reduce the disposal of waste plastics and relieve the dependence of fossil fuels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Dielectric barrier discharge (DBD) was employed to assist to convert biomass into aromatic hydrocarbons under the vacuum pyrolysis and zeolite catalysis conditions. This study was to investigate the ...selectivity and stability of HZSM-5 modified by Ti, Ni, and Ni-Ti. The texture and acidity of different modified catalysts varied greatly. Ti modification strengthened the cracking removal of carbon and oxygen, while Ni-modified version improved hydrogen transfer capacity. Bimetallic modification increased the HHV to 36.93 MJ/kg, and obtained a compromised yield of 28.10%. Hydroxyl was difficult to completely remove due to hydrophilicity, carbonyl removal was better, and refined bio-oils had a high aromatic degree, of which, bimetallic modification increased the selectivity of MAHs to 76.61% and the refined bio-oil was more suitable to be used as gasoline additives. Although the aromatization performance of Ti-modified version was weaker than that of Ni-modified version, its anti-coking performance was better. The acidity adjustment of bimetallic modification cooperated with the synergistic effect of metal species and discharge, so that the difficulty of carbon deposition was increased significantly. The high-temperature catalytic coke was not distinguished and the low-temperature thermal coke mainly deposited on the outer surface was further reduced for bimetallic modified catalyst. Therefore, the Ni-Ti/HZSM-5 assisted by DBD exhibited better potential in improving the selectivity of aromatic hydrocarbons and enhancing the stability of zeolite catalyst.
•Metal modified HZSM-5 assisted by DBD was applied for one-stage aromatics production.•Ti and Ni modification respectively improved cracking and hydrogen transfer capacity.•Bimetallic modification increased MAHs selectivity to 76.61% and HHV to 36.93 MJ/kg.•Difficulty of carbon deposition was increased due to acid adjustment and DBD synergy.•Bimetallic version had no catalytic coke and reduced thermal coke on the outer surface.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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