condition	area concentration/%(mn2+)	area concentration/%(mn3+)	area concentration/%(mn4+)
before plasma	1	70	29
room temperature	10	86	4
160℃	31	69	0



The area fractions of Mn$^{2+}$, Mn$^{3+}$, and Mn$^{4+}$ in Mn 2p$_{3/2}$ spectra under different conditions. From left to right: before plasma reaction, after RT reaction, after 160 $^\circ$C (433 K) reaction. Each bar is stacked from bottom to top with Mn$^{2+}$ (green), Mn$^{3+}$ (purple), and Mn$^{4+}$ (orange).