Biomass-derived carbon electrodes: Key parameters for understanding the electrocatalytic performance

The conversion of biomass into carbon materials has become an essential pillar of sustainability in electrochemical technologies. However, biomass-derived carbons and their electrodes are complex materials. This opinion article raises concerns about the need to correlate physicochemical properties of these carbon materials with those of the biomass precursor, the electrode composition and the electrode/electrolyte interface to rationalize the comprehension of their electrocatalytic performance. The electrocatalytic activity of biomass-derived carbons in aqueous environments is discussed for several reactions of interest in terms of the nature and stability of electroactive sites and the ability to form radicals. All these are strongly related to the characteristics of the carbon material (composition, type of functional groups, porosity, structural order) and the manufacture of those electrodes. Concerns are also raised about the ambiguities and misconceptions associated to the lack of consensual terminology on biomass-derived carbons. Finally, recommendations are presented when reporting the electrocatalytic activity of biomass-derived carbons; emphasis should be paid to demonstrate the reproducibility of biomass-derived carbon electrodes and their stability through long-term electrocatalytic assays.