La-PbO₂ electrodeposited porous carbon and its electrocatalytic performance in treating organic pollutants

The anode material has a great influence on the redox reaction during the electrocatalytic degradation. This work demonstrates a new anode material (namely La-PbO₂@C-TOCNF/CGG) fabricated via a facile electrodeposition process, in which the carbon aerogel was obtained from the sequential process of freezing-drying and carbonization of hydrogel containing TEMPO-oxidized cellulose nanofiber (TOCNF) and cationic guar gum (CGG). In particular, a carbon aerogel (denoted as C-TOCNF/CGG) exhibited good electrical conductivity, electron diffusion ability and large surface area. Its hierarchical porous structure allowed better diffusion of electrolyte solution and dispersion of La-PbO₂ particles, improving the electrocatalytic activity. This La-PbO₂@C-TOCNF/CGG exhibited good electrocatalytic degradation performance in treating methyl orange solution with a degradation ratio of 85.26 % within 180 min. Additionally, La-PbO₂@C-TOCNF/CGG also has excellent degradation rates for methylene blue (91.5 %) and Congo red (94.5 %). The cyclic electrodeposition and degradation analysis verified the robustness and recyclability of this C-TOCNF/CGG. This La-PbO₂@C-TOCNF/CGG also showed good performance in treating industrial dyes-contaminated wastewater (20 mg/L) and antibiotic drugs-containing water (10 mg/L) at the efficiency of 88.7 % and 73.2 % at 50 mA cm^-2 within 120 min, respectively. This work demonstrated a promising way to make the most of biomass-derived hydrogels in designing electrocatalyst for wastewater treatment.