Waste corn stalk-derived biomass carbon materials as two-electron ORR electrocatalysts for dye contaminant degradation and water disinfection.

Porous carbon materials as efficient two-electron oxygen reduction reaction (ORR) electrocatalysts for on-situ production of hydrogen peroxide (HO) is one of the promising alternatives to the traditional anthraquinone process. Herein, waste corn stalks-derived porous carbon composites (CSDC-O, Fe/CSDC-O-12) were developed as two-electron ORR electrocatalysts for HO generation and the further organic dye pollutants degradation and water disinfection. The high-temperature pyrolysis and oxidation treatment enriched the hierarchical porous structure of the biomass carbon materials, improved graphitization degree and the content of oxygen-containing functional groups, which facilitated the increase of active sites density, the mass and charge transfer rates acceleration, and the active and selective HO generation. Based on the remarkable two-electron ORR selectivity and long-term stability in both alkaline and acidic media exhibited by Fe/CSDC-O-12, it was used to completely degrade 25 mg L of rhodamine B and methyl orange within 70 and 80 min, respectively. Moreover, the CSDC-O electrocatalyst demonstrated disinfection efficiency exceeding 99.9999 % against Escherichia coli and Staphylococcus aureus within 20 and 60 min, respectively. Thus, our work provides a feasibility verification for the transformation of abundant biomass corn stalk waste into low-cost, sustainable, and high-value-added two-electron ORR electrocatalysts, and expand their application in dye contaminant degradation and water disinfection.