Tuning surface phosphorus chemistry in metal-free carbon electrocatalysts for enhanced hydrogen evolution

Abstract

The precise modulation of phosphorus species and physicochemical properties in metal-free carbon materials holds significant potential for enhancing their electrocatalytic performance in the hydrogen evolution reaction (HER). In this study, we precisely tune the phosphorus species during the pyrolysis of phytic acid (PA). Pluronic (R) F127 acts as a protective agent, preventing the close proximity of phosphorus groups in PA molecules during pyrolysis. This interaction inhibits the formation of polyphosphoric groups during carbonization and leads instead to isolated P functionalities embedded in carbon basal planes. Comprehensive characterization, including cross-polarization magic angle spinning solid-state 31P NMR, XPS, and DFT simulations identified the phosphorus species and elucidated their structural and electronic properties. The precise tuning of phosphorous functional groups enabled by Pluronic (R) F127 in metal-free carbon materials boosting the phosphorous based state-of-theart HER catalytic performance. These findings underscore the underexplored potential of surfactants beyond morphological templating, offering a powerful strategy for tailoring surface chemistry and advancing the design of next-generation metal-free electrocatalysts.