Enhancing carbonized wood cathodes for Electro-Fenton efficiency: Structural evolution contributions to H2O2 generation

Electro-Fenton (EF) technology faces significant challenges, including the high cost of catalysts, complex electrode preparation, and limited energy utilization efficiency. Wood-based block cathodes (WBCs), as cost-effective and sustainable materials for EF technology, remain challenging due to limited theoretical understanding of the two-electron oxygen reduction reaction (2e − ORR) for efficient H 2 O 2 production. In this study, low-tortuosity, mesoporous WBCs were fabricated via carbonization without activation or modification, serving as effective binder-free cathodes for H 2 O 2 generation. The electrochemical properties influenced by structural evolution of WBCs were systematically examined, revealing how variations in pyrolysis temperature influenced their performance. The unique "long-range order, short-range disorder" (LRO-SRD) structure facilitated mass transfer, while the presence of graphite-like carbon and defects enhanced electron transfer and O₂ adsorption. Among the various samples, the carbonized wood cathode prepared at 900°C (WBC900), achieved the highest H 2 O 2 yield of 235.23 mg L −1 h −1 and maintained stability over 10 cycles, effectively degrading dyes within 30 minutes. This study provides valuable insights into the design of cost-effective, sustainable WBCs for EF applications by highlighting the relationship between structural evolution and performance. • Wood-derived carbon structure–electron transfer property relationship was studied. • Wood-derived pore structure–mass transfer performance relationship was explored. • The 2e − ORR behavior was comprehensive assessed over wood block cathode. • The concept of ‘long range order, short-range disorder’ was introduced. • A simple 3D wood-derived carbon structural model was established.