N-doped CoAl oxides from hydrotalcites with enhanced oxygen vacancies for excellent low-temperature propane oxidation

Lewis Acid Site Al-Promoted CoAl2O4/CoO Electrocatalyst for Efficient Electrochemical Production of H2O2 toward On-Site Pollutant Degradation

“… Figure b–d shows the O 1s, Co 2p, and Al 2p XPS spectra of CoAl 2 O 4 /CoO, CoAl 2 O 4 /Al 2 O 3 , Co 3 O 4 , and Al 2 O 3 . The three peaks at 531.8, 530.2, and 528.8 eV in O 1s XPS spectra (Figure b) are associated with hydroxyl species oxygen, adsorbed oxygen, and lattice oxygen, respectively. , The CoAl 2 O 4 /CoO and Al 2 O 3 have the same bonding modes of O. This is attributed to the addition of metal Al and CN in the synthesis process of the catalyst maintaining lattice oxygen.…”

“…Compared with the CoAl 2 O 4 /Al 2 O 3 and Co 3 O 4 , the CoAl 2 O 4 /CoO has the highest Co 2+ content (Table S1), which is consistent with the valence states of Co in the CoO and CoAl 2 O 4 . It is concluded that Co 2+ is beneficial to the improvement of ORR performance. , The spectra of Al 2p XPS (Figure d) can be convoluted into three components at 74.9, 73.6, and 72.2 eV, which are related to Al–O, octahedral Al 3+ ions, and tetrahedral Al 3+ ions, respectively. , Compared with CoAl 2 O 4 /Al 2 O 3 , the satellite peaks of octahedral and tetrahedral Al 3+ ions in CoAl 2 O 4 /CoO have the positive shifts of 0.9 and 0.8 eV, respectively. In addition, the slight positive shifts of octahedral and tetrahedral Al 3+ ions in Al 2 O 3 compared to CoAl 2 O 4 /CoO are 0.4 and 0.9 eV, respectively.…”

“…37,38 The CoAl 2 O 4 /CoO and Al 2 O 3 have the same bonding modes of O. This is attributed to the addition of metal Al and CN in the synthesis process of the catalyst maintaining lattice oxygen.The Co 2p XPS spectra of CoAl 2 O 4 /CoO, CoAl 2 O 4 /Al 2 O 3 , and Co 3 O 4 catalysts (Figure 2c) reveal two major peaks attributed to Co 2p 1/2 and Co 2p 3/2 .…”

“…18,37 The spectra of Al 2p XPS (Figure 2d) can be convoluted into three components at 74.9, 73.6, and 72.2 eV, which are related to Al−O, octahedral Al 3+ ions, and tetrahedral Al 3+ ions, respectively. 38,40 Compared with CoAl 2 O 4 /Al 2 O 3 , the satellite peaks of octahedral and tetrahedral Al 3+ ions in CoAl 2 O 4 /CoO have the positive shifts of 0.9 and 0.8 eV, respectively. In addition, the slight positive shifts of octahedral and tetrahedral Al 3+ ions in Al 2 O 3 compared to CoAl 2 O 4 /CoO are 0.4 and 0.9 eV, respectively.…”