Boron‐Nitrogen‐Edged Biomass‐Derived Carbon: A Multifunctional Approach for Colorimetric Detection of H₂O₂, Flame Retardancy, and Triboelectric Nanogenerator

Abstract

Enhancing the concentration and type of nitrogen (N) dopants within the Sp2‐carbon domain of carbon recycled from biomass sources is an efficient approach to mimic CNT, GO, and rGO to activate oxidants such as H2O2, excluding toxic chemicals and limiting reaction steps. However, monitoring the kind and concentration of N species in the Sp2‐C domain is unlikely with thermal treatments only. A high temperature for graphitization reduces N moieties, leading to low electron density. This inhibits H2O2 adsorption and activation on catalyst surfaces. In this study, coffee waste (CW) is converted into B, N‐doped biochar (BXNbY) using boric acid‐assisted pyrolysis (H3BO3 mass = X and carbonization temperature = Y) under N2 to overcome the challenge. The B dopant regulates the concentration and type of N, provides Lewis's acid sites, and converts graphitic‐N to pyridine‐N in BXNbY. The optimized B3Nb900 exhibits excellent colorimetric sensing performance toward H2O2 with a low detection limit (36.9 nM) and high selectivity in the presence of many interferences and milk samples due to high pyridinic‐N and Sp2 domain sizes. Interestingly, B enhances other properties of N‐containing CW‐derived carbon and introduces self‐extinguishing and tribopositive properties. Hence, BXNbY‐coated polyurethane foam shows excellent flame retardancy and energy harvesting performance.