Selective Hydroxylation of Carbon Fiber Paper for Long‐Lasting Hydrophilicity by a Green Chemistry Process

Abstract This study reports the selective hydroxylation of macroscopic carbon surfaces that renders initially hydrophobic fiber paper hydrophilic for more than one year (62 weeks) so far. long time sustained hydrophilicity is unprecedented and transforms utility materials. Quantification surface oxygenates a systematic series 13 chemical treatments reveals hydroxyls are predictors long‐lasting hydrophilicity. The rapid, mild, acid‐free, transition‐metal‐free treatment does not leave residues, inhibits overoxidation graphitic beyond hydroxyls, introduces highest edge density on surfaces, without altering mesostructure network architectures lowering flexural strength paper. Graphitic edges required enhanced stability retain threshold amount adsorbed water, which necessary keeping hydrophilic. Application as high‐surface‐area working electrode supports alkaline water oxidation catalyzed by [NiFe]‐layered double hydroxide nanosheets demonstrates factor 60 higher mass activity compared to catalysis flat basal‐plane highly ordered pyrolytic graphite electrodes.