Boron-Nitrogen-Edged Biomass-Derived Carbon: A Multifunctional Approach for Colorimetric Detection of H 2 O 2 , Flame Retardancy, and Triboelectric Nanogenerator.

Enhancing the concentration and type of nitrogen (N) dopants within the Sp 2 -carbon domain of carbon recycled from biomass sources is an efficient approach to mimic CNT, GO, and rGO to activate oxidants such as H 2 O 2 , excluding toxic chemicals and limiting reaction steps. However, monitoring the kind and concentration of N species in the Sp 2 -C domain is unlikely with thermal treatments only. A high temperature for graphitization reduces N moieties, leading to low electron density. This inhibits H 2 O 2 adsorption and activation on catalyst surfaces. In this study, coffee waste (CW) is converted into B, N-doped biochar (B X Nb Y ) using boric acid-assisted pyrolysis (H 3 BO 3  mass = X and carbonization temperature = Y) under N 2 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 B X Nb Y . The optimized B 3 Nb 900 exhibits excellent colorimetric sensing performance toward H 2 O 2 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 Sp 2 domain sizes. Interestingly, B enhances other properties of N-containing CW-derived carbon and introduces self-extinguishing and tribopositive properties. Hence, B X Nb Y -coated polyurethane foam shows excellent flame retardancy and energy harvesting performance.