Constructing boosted charge separation for efficient H2O2 production and pollutant degradation by highly defective ZnIn2S4/ carbon doped boron nitride

Abstract

Solar-driven photocatalytic production of H2O2 as a promising environmentally-friendly approach has been applied as a chemical reagent and for enhancing photocatalytic remediation. However, this process is still limited by unsatisfactory efficiency and hard separation of photogenerated charge carriers. Herein, we design a dual pathway to improve hydrogen peroxide production by establishing a 2D/2D heterojunction between carbon-doped boron nitride (BCN) and defective zinc indium sulfide (ZIS). The introduction of multiple vacancies and dopants at the interface successfully promoted the interfacial charge transfer and peroxide generation. The Z-scheme heterojunction establishes a built-in electronic field, facilitating continuous electron accumulation and depletion, thereby inducing band bending. As a result, the optimized BCN/ZIS-30 composite (>420 nm wavelength) exhibits 925 μmol/g/h in pure water with no other additions and advances this production to 2006.1 μmol/g/h (2 times as defective ZIS and 12.1 times as BCN) under the existence of isopropanol and aeration. Mechanism investigation indicated that H2O2 is generated via a two-step electron reduction route and water oxidation reaction. The generated H2O2 successfully constructs a self-photo-Fenton system by forming hydroxyl radicals. Accompanied by strong oxygen activation ability, the photo-Fenton system also exhibits rapid degradation of antibiotics with 95 % elimination in 60 minutes. The practical applicability of this photocatalyst was demonstrated through real water remediation tests, exhibiting its effectiveness in removing antibiotics, COD, and total ammonia nitrogen, highlighting its potential for practical water treatment applications. This work provides a novel idea on constructing heterojunction materials for energy saving and water remediation.