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Chemical stability of La 2O 3 in carbonized and uncarbonized La 2O 3 Mo cathodes was studied by in situ XPS analysis. Experimental results show that chemical stability of La 2O 3 is not good enough. In vacuum and at high temperature, oxygen can be dissociated from the lattice of La 2O 3 in the uncarbonized La 2O 3 Mo cathode. Binding energy shifts of La?3d5/2 and La?3d3/2 core peaks, and obvious decrease of satellite peak intensity in La?3d doublet with increasing temperature show that metallic La appears at carbonized La 2O 3 Mo cathode surface at high temperature.
Chemical stability of La 2 O 3 in carbonized and uncarbonized La 2 O 3 Mo cathodes was studied by in situ XPS analysis. Experimental results show that chemical stability of La 2 O 3 is not good enough. In vacuum and at high temperature, oxygen can be dissociated from the lattice of La 2 O 3 in the uncarbonized La 2 O 3 Mo cathode. Binding energy shifts of La ~ 3d5 / 2 and La ~ 3d3 / 2 core peaks, and significantly decrease of satellite peak intensity in La ~ 3d doublet with increasing temperature show that metallic La appears at carbonized La 2O 3 Mo cathode surface at high temperature.