TRANSFORMING BIOMASS INTO HIGH-PERFORMANCE CARBON-BASED ELECTRO-CATALYSTS FOR SUSTAINABLE OXYGEN, WATER, AND CO₂ CONVERSION REACTIONS

Abstract

Introduction The high requirement for sustainable and cheap electro-catalysts for clean energy applications has driven certain exploration of bio-resources derived-carbon materials. Heteroatoms and hierarchical structures can be provided by Biomass based precursors which show a high potential in multifunctional electro catalysts for ORR, HER, OER and CO₂RR. Objective: The purpose of this work is to develop high-performance carbon-based electro-catalysts from biomass resource using heteroatom-doping and structural engineering for boosting the electro catalytic activity in ORR, HER, OER, and CO₂RR. Methods: After hydrothermal carbonization, biomass was paralyzed at different temperatures using nitrogen and phosphorus as dopants. The products were then characterized by SEM, TEM, XRD, Raman spectroscopy, and BET surface area analysis. Linear sweep voltammetry, chrono-amperometry, and electrochemical impedance spectroscopy were used to assess the electrochemical performance in alkaline and neutral electrolytes. Results: The as-obtained N, P-co-doped biomass-derived carbon as electro catalyst presented an onset potential of 0.91 V (vs. RHE) for ORR with almost ideal four-electron ORR process. In the case of HER, the over potential required to deliver a current density of 10 mA cm⁻² was 112 mV, while for OER, the catalyst achieved 10 mA cm⁻² at 1.51 V. CO₂RR tests indicated good Faradaic efficiency (89%) for CO production, along with exceptional long-term stability. The superior performances of CO2 adsorption were ascribed to synergistic dopant, large surface area, and good pore structure. Conclusion: The biomass-to-doped carbon framework transformation represents a green and large-scale platform for the production of multifunctional electro-catalysts and the evolution of sustainable energy conversion platforms.