Biomass-inherent nitrogen doping in utilized chopsticks carbon for alkaline electrolysis

Abstract

As the requirement for the generation of green hydrogen enhances, there is a critical necessity for electrocatalysts which are inexpensive, and resource efficient. In this research, we present a facile and chemically unmodified technique to transform utilized chopsticks doped with urea, overabundant single-use biogenic waste, into biochar for water splitting reactions. The biochar was prepared through straightforward pyrolysis devoid of reagent activation or doping of metals, affirming a minimalist and sustainable approach. The chopsticks derived biochar displayed notable dual functional electrocatalytic performance, attaining an overpotential of 333 mV for hydrogen evolution reaction (HER) and 351 mV for oxygen evolution reaction (OER), in an alkaline media at 10 mA cm⁻². Further, the catalyst delineated stable activity over prolonged electrolysis, accentuating the robustness and the feasibility of biochar for real-time applications. The improved catalytic performance is attributed to the nitrogen species, from urea, that modulate the electronic, structure, create abundant active sites, and accelerate interfacial charge transfer. This research introduces an unexplored route to untreated biochar from post-consumer chopsticks that could directly serve as a promising and renewable electrocatalyst for both HER and OER, independent on expensive materials or complex preparation procedures. With the exploitation of single-use biomass residue via an extensible approach, this study provides to solid waste utilization and evolution of off-grid hydrogen energy systems.