Development of graphitized biochar derived from cyanobacterial for improved electrocatalytic hydrodehalogenation performance

Palladium (Pd) is recognized as a promising electrocatalyst for electrocatalytic hydrodehalogenation (ECH). However, the agglomeration-prone nature of Pd nanoparticles diminishes active site accessibility, significantly compromises their atomic utilization efficiency, thereby limiting ECH performance. To overcome this issue, a nickel (Ni)-catalyzed graphitized cyanobacterial biochar (GCB Ni ) has been developed through catalyst screening and process optimization. The incorporation of Ni enhanced the ordering of carbon arrangement in the biochar, endowing GCB Ni with a highly graphitized structure, superior electrical conductivity, and substantial surface area. Pd nanoparticles were supported on GCB Ni to fabricate the Pd@GCB Ni catalyst. The Pd@GCB Ni /CC electrode exhibited well-dispersed Pd nanoparticles, where GCB Ni modulated the Pd(0)/Pd(II) ratio and promoted the exposure of Pd(111) crystallographic planes. This structural modification increased accessible active sites, facilitated reactive atomic hydrogen (H*) generation, and improved both adsorption of florfenicol (FLO) and desorption of intermediate products. The Pd@GCB Ni /CC electrode demonstrated exceptional FLO removal efficiency (99.6 %±0.4 %) with an apparent rate constant ( k obs ) of 1.01 ± 0.08 h −1 . Remarkable stability was maintained through ten consecutive operational cycles, with superior ECH performance towards various halogenated organic pollutants containing different halogen substituents. This research provides novel insights into cyanobacterial resource utilization and establishes an effective support modulation strategy for developing high-performance ECH catalysts.