Figure 2

XPS survey scans of biochar and BCRNF on indium foil. Analysis of the biochar surface modification induced by hydrothermal synthesis. XPS scanning spectra of biochar (a) and BCRNF (e) show three major peaks of carbon, nitrogen, and oxygen. XPS high resolution survey scan of C1s (b,f), N1s (c,g) and O1s (d,h) region of biochar and BCRNF.