A nanoscale observation to explain the discrepancy of electron exchange capacities between biochar containing comparable surface redox-active moieties

Abstract Biochar, possessing electron exchange capacities (EEC), is generally involved in environmental redox reactions due to the presence of redox-active moieties (RAMs). The phenomenon that chars containing comparable RAMs possess differential EEC revealed accessibility important properties. However, many studies have focused on type RAMs, whereas distribution has been insufficiently investigated. Herein, we achieved nanoscale observation electroactive surface six using a conductive atomic force microscope. For two specific kinds with submicron particles and opposite current distributions, took up only 1–4‰wt biochar accounting for approximately 30–50% electron-donating capacity (EDC), electron-accepting (EAC) became 87% 1.40 times as before after removing particles, respectively. Meanwhile, combined impact topography (that uneven resulted outstanding by enhancing accessibility) was clarified. Furthermore, direct evidence link between char structure condensed aromatic structures were indispensable EAC while both heteroatoms amorphous aromatics contributed EDC) established. These findings can aid understanding functions biotic abiotic processes. Graphical