A series of Cd-doped NiO catalysts were prepared and tested in the N 2 O catalytic decomposition reaction. In comparison with NiO, it was found that the Cd 0.04 Ni catalyst showed higher N 2 O decomposition activity in the temperature range of 300–450 °C with or without O 2 , and lower activation energy (77.8 kJ mol −1 ). The incorporation of Cd into the NiO lattice was verified by X-ray diffraction (XRD) patterns and Raman spectra. This led to the distortion of the original NiO structure and weakened the Ni-O bond. X-ray photoelectron spectroscopy (XPS) results showed that compared with NiO and CdO, Cd 0.04 Ni possessed higher Ni 2+ and Cd (n+1)+ contents, which might have been induced by the electron transfer behavior between CdO and NiO. A possible mechanism for active site regeneration and O 2 desorption over Cd 0.04 Ni was proposed. The Cd 0.04 Ni catalyst also exhibited good resistance to NO and O 2 .
Fe-based heterogeneous catalytic advanced oxidation processes show great potential for treating wastewater. However, catalyst instability often hinders their practical use, mainly due to the slow regeneration of Fe2+sites. Herein, we developed a Fe3S4/WO3catalyst, where the electron-rich Wx and Sx sites promoted efficient electron transfer, enabling continuous regeneration of Fe2+active sites on the catalyst surface. The Fe3S4/WO3catalyst exhibited outstanding degradation efficiency for tetracycline (TC) in the peroxymonosulfate (PMS) system, achieving a 92.5% removal efficiency, significantly higher than its individual components of Fe3S4(52.8%), WO3(43.1%), and WS2(53.2%). Moreover, the Fe3S4/WO3/PMS system demonstrated a broad operational pH range (3.0–9.0), excellent degradation efficiency for various emerging pollutants, minimal interference from background electrolytes and organic matter, and strong stability in real water treatment. Chemical scavenger tests and electron paramagnetic resonance (EPR) analysis confirmed that the oxidative degradation of TC was driven by multiple reactive species, including SO4•−,•OH,•O2−, and1O2. This study provides a novel strategy for regulating active sites in Fe-based catalysts to ensure sustained performance, offering a pathway for the rational design of next-generation Fenton-like catalysts for efficient and sustainable micropollutant removal from wastewater.
Hui Zhang,Hui Han,Xuan Yang,Hongyu Ma,Zhifei Song,Xuqiang Ji
Active-site regeneration from d-band-center control engineering and electronic redistribution based on target-atom implantation is of enormous importance for efficient water oxidation. Here, low-activity Co catalytic sites of MgCo2O4 are reactivated for large-current (500 mA cm−2) and high-efficiency water oxidation through vanadium-atom electronic affinity synergy with Mg sites toward charge rearrangement around Co sites. Interestingly, very little vanadium (1.3 wt%) was implanted into MgCo2O4 to achieve atom-scale structure tailoring and electronic redistribution, reversing the Mg suppression effect on Co-site water oxidation of MgCo2O4. Vanadium-implantation-tailored MgCo2O4 coupled with MgO (V–MgCo2O4@MgO) exhibits significantly enhanced oxygen evolution reaction performance, with low overpotentials of 240 and 290 mV for 100 and 500 mA cm−2, respectively, in 1 M KOH. Operating at 500 mA cm−2, V–MgCo2O4@MgO has good catalytic stability for at least 20 hours. This work constructs excellent catalysts through atomic-level structural regulation and provides a new perspective for the principle of electronic-affinity synergy between V and Mg species toward Co–O bond optimization.
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