Exploring the Impact of Ni Doping on Bagasse Biochar and Its Efficient Hydrogen Production via Assisted Water Electrolysis

Abstract

Heteroatom doping in carbon matrices has been widely used to prepare efficient carbonaceous electrocatalysts. Biochar-assisted water electrolysis (BAWE) is a promising hydrogen production method that can efficiently utilize waste biomass. However, it is often limited by the slow anode biochar oxidation reaction (BOR). In addition, pure biochar typically lacks enough active catalytic sites; hence, its electrochemical reactivity is unsatisfactory. Herein, Ni is doped into bagasse biochar to improve its BOR. Its electrochemical properties and hydrogen production performance are measured using linear sweep voltammetry, electrochemical impedance spectroscopy, and chronopotentiometry. The reaction characteristics of the bagasse biochar are analyzed. The impact of its physiochemical properties on its oxidation process is discussed. Compared to the undoped biochar, the Ni-doped biochar shows a larger specific surface area, a higher degree of graphitization, and stronger biochar oxidation reactivity (including a lower onset potential and larger electric current density), which significantly increase the electric current density and hydrogen production. This study provides a beneficial strategy for improving BAWE.