After cabonization and activation, biomass cellulose were transformed to biochar. But when I collected the XRD specturm, a stranger peak at 10° appeared. how could explain this peak.
I suggest three ways for you. First, give your sample for data analysis, which they also give you along with JCPDS analysis. You can also use the relevant software, where there is a library as a reference for all kinds of materials, and thirdly, read related articles and compare the results with them.
You should also use other analyzes such as the infrared spectrum.
For XRD, the figure shows a remarkable and mysterious description of the x-y axes (cycle number - capacitance retention). Is it even a diffraction pattern? If so, the peak at diffraction angle 10o 2 theta may be a consequence of insufficient sample size. The irradiated area was probably significantly larger than the size of the sample.