Ковер

Ковер

Результаты (английский) 1:

Carpet

Результаты (английский) 2:

The surface composition of a catalyst has an important effect on the catalytic performance. The survey scan spectra of different Fe- based catalysts are compared in Fig.3. According to the peaks Thereinto, Fe– C bonds are generally ascribed to carbides, such as Fe5C2 . C1s XPS spectra are also provided in Fig. S4 (ESI). The C1s spectrum can be deconvoluted into three peaks assigned to C– O bond (286.8 eV), C– O bond (284.9 eV) and C– C/C– C bond (283.8 eV) . Compared to Fe/C catalyst, Fe/C-1EDA shows a higher content of Fe– C, a crucial species for the catalytic hydrogenation of CO2 to hydrocarbons (Table S1 and Fig. 3a). However, the Fe– C content on the Fe/C-2EDA is lowered again, which indicates that a suitable N- addition amount is vital. Nevertheless, the concentration of FeII is still significantly larger than that of Fe/C catalyst. This indicates that doping of nitrogen atoms has two promotional effects: one is to improve the reduction of iron oxides, and the other is to promote the generation of active carbides. Generally, Fe3O4 is responsible for converting CO2 to adsorbed CO intermediates, while Fe– C is responsible for the conversion of CO to hydrocarbons. Surface content of Fe3O4 (Fe2O3⋅FeO) can be reflected according to the FeII content to some extent. Therefore, both the improved reduction and carbonization behavior can boost the improvement of reaction performance. With the introduction of alkali metal K, in addition to the improvement of carbonization behavior, the catalysts (FeK/C-1EDA and FeK/C, Table S1) exhibit a higher composition of low-valence iron species.