MgO-decorated phosphorus-doped biomass-derived carbon as a high-activity catalyst for sodium borohydride methanolysis

Abstract

This study introduces a novel approach for sustainable hydrogen generation utilizing waste biomass conversion and nanomaterial engineering. The activated carbon was synthesized from mandarin peel waste through sodium hydroxide-mediated chemical activation (MPAC), followed by strategic phosphorus functionalization via phosphoric acid treatment. The resulting P-doped carbon framework served as a host matrix for magnesium oxide (MgO) nanoparticles, which were anchored through a controlled hydrothermal deposition process. The resulting MgO@P-doped MPAC hybrid catalyst was investigated for sodium borohydride (NaBH4) methanolysis, demonstrating exceptional hydrogen evolution kinetics of 63190 mL min−1g−1—a remarkable 14-fold enhancement compared to P-doped MPAC without MgO incorporation (4497 mL min−1g−1). Physicochemical characterization revealed uniformly dispersed MgO nanoparticles (average diameter: 5.83 nm) across the carbon framework, creating abundant catalytically active interfaces. The hybrid catalyst exhibited a favorable activation energy of 32.54 kJmol-1 and maintained 80 % of its initial hydrogen generation efficiency after multiple five reaction cycles, indicating excellent operational stability. The superior performance stems from synergistic interactions between phosphorus moieties and MgO nanoparticles, facilitating optimized hydrogen release kinetics through enhanced active site accessibility and electronic modulation. This work demonstrates the viability of transforming agricultural waste into high-performance catalytic materials for clean hydrogen energy applications.