Huiao Liu,Yan Li,Ziying Hu,Xinhui Hao,Hongpeng Jia,Jing Chen,Can-Zhong Lu
A wire like CeO 2 catalyst (CeO 2 -w) was obtained after the calcination of the precursor at 400 °C, which was prepared by the freeze-drying method for the first time. It shows good performance for catalytic oxidation of toluene with T 90 of 220 °C, which is much better than the CeO 2 catalysts with other structures prepared by the different methods. The good performance of CeO 2 -w is due to the bigger pore volume, more active oxygen species, more oxygen vacancies, better low temperature reducibility, higher surface area normalized reaction rates and lower E a value. Additionally, the CeO 2 -w catalyst exhibits good water resistance and catalyst stability. In situ DRIFTS indicates the catalytic oxidation of toluene on CeO 2 -w undergoes the progress of toluene → benzaldehyde → benzoic acid → maleic acid → CO 2 and H 2 O. This work affords a new idea to prepare high active CeO 2 nanowire catalysts for catalytic oxidation of toluene, and open an efficient way for the construction of CeO 2 based composite catalysts for VOCs degradation.
Developing high-efficiency, low-cost, and durable bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is greatly desirable and challenging. Herein, a highly active and durable nitrogen-doped CoP coupled CeO 2 nanowire heterostructure ( N -CoP/CeO 2 ) electrocatalyst is prepared on carbon cloth. The resultant N -CoP/CeO 2 exhibits superb catalytic activities for OER and HER, featuring low overpotentials of 215 and 74 mV at 10 mA cm −2 in 1.0 M KOH. The N -CoP/CeO 2 assembled water electrolyzer has super stability, which needs relatively low cell voltages of 1.52 V@10 mA cm −2 over 42 days (≈95.9 % retention) and 1.80 V@400 mA cm −2 over 21 days (≈94.4 % retention), outperforming most reported cost-effective electrocatalysts. Theoretical calculations reveal that the metallic heterostructure interfaces of N -CoP/CeO 2 possess a fast electron transfer pathway, optimized adsorption/desorption process of reactive intermediates, and reduced reaction energetic barriers, thus enhancing the electrocatalytic activity. Additionally, the robust three-dimensional configuration and the oxygen vacancies-rich CeO 2 component in N -CoP/CeO 2 are regarded as significant contributors to improving stability and promoting long-term durability.
Although WO 3 with high theoretical capacitance has a future in the field of energy storage, its electrode processing to obtain high capacitance is still a challenge. Here, we propose an innovative electrode structure design by utilizing PEDOT and PEDOT:PSS to sequentially assemble with the oxygen vacancies-enriched WO 3 and WO 3 -CeO 2 hybrid nanowires on the glassy carbon (GC). As-prepared PEDOT:PSS/WO 3 /PEDOT/GC and PEDOT:PSS/WO 3 -CeO 2 /PEDOT/GC electrodes show high areal capacitance of 1139.6 and 1310 mF cm −2 at 2 mA cm −2 , respectively, greater than 822.3 mF cm −2 of the WO 3 -PTFE-C/GC. The asymmetric supercapacitor based on PEDOT:PSS/WO 3 -CeO 2 /PEDOT and PEDOT:PSS/RuO 2 /PEDOT electrodes works at 1.6 V high working voltage, delivers an energy density of 0.61 Wh m −2 at power density of 8.22 W m −2 . Therefore, the electrode structure design will be suitable to improve the capacitance performance of other low-conductivity active materials.
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