Tuning Sugar Biomass Waste Conversion for the Preparation of Carbon Materials for Supercapacitors and Catalysts for Oxygen Reduction

Agriculture is the most massive material circulation activity of humans, with significant annual volumes of production as well as substantial amounts of waste. Transforming agricultural wastes into high-value-added products is the key to sustainable development with efficient usage of renewable resources. The present study demonstrates the fine-tuning of the sugar beet pulp processing to access two types of materials for cutting edge applications-supercapacitors and fuel cells. Alkaline fine-tuning results in N,O-doped carbon material (CM) with an advantageous combination of surface area and morphology that allows to achieve high specific capacitance (308 F g(-1)), and excellent stability (>10 000 charge/discharge cycles). Not limited to the CM preparation and characterization, a real device is created in the present study to demonstrate the efficient usage of the carbon electrode in the form of the assembled coin cell. Acidic fine-tuning, in contrast, yields a methodology for P,N,O-doped material and optimizes to form active sites with electrocatalytic activity in the oxygen reduction reaction that is used for electricity production in proton-exchange membrane fuel cells. The developed approach demonstrates the tuning of functional properties and morphology of CMs under experimentally simple conditions using conventional reagents (KOH and H3PO4) and opens up new directions in the circular biomass usage projects.