Hydrogen production and electrochemical energy storage with a dual-function application of boron and oxygen-doped biomass-based porous activated carbon-based composite material

Abstract

In this study, boron (B) and oxygen (O) atoms were doped into activated carbon (AC) derived from pomegranate peel biowaste through potassium hydroxide (KOH) activation using boric acid. This material (B, O doped ACPP) is used both as a metal-free catalyst in the production of hydrogen (H2–P) with sodium borohydride (NaBH4) in methanol (CH3OH) and as an electrode for a supercapacitor in the energy storage field. The results provide significant increases in both application areas with the same material. The TEM analysis revealed the formation of uniformly distributed nanoscale particles (∼8.25 nm), which further increases the accessible surface area and shortens ion diffusion paths. The completion time of H2 release by NaBH4 reaction in only CH3OH is 16 min. However, the H2–P reaction of NaBH4 in CH3OH with B, O doped ACPP is completed in 7 min. H2 production rate (HGR) value obtained using B, O doped ACPP with 0.25 g NaBH4 is 18471 mLmin−1gcat−1. A substantial enhancement of approximately 2.5 times in specific capacitance is observed for B, O-doped ACPP compared to ACPP. At a current density of 1.6 A g−1, the B, O-doped ACPP-GCE electrode demonstrates excellent cycling stability, 87.8 % of its capacitance after 10.000 cycles. The charge transfer resistance (Rct) values were measured to be 41.1 Ω for ACPP and 17.7 Ω for B, O doped ACPP.