In situ fabrication of N-doped Ti3C2Tx-MXene-modified BiOBr Schottky heterojunction with high photoelectron separation efficiency for enhanced photocatalytic ammonia synthesis

Abstract

NH3 synthesis under ambient conditions remained great challenge owing to the strong NN bond energy, high ionization energy, and poor proton affinity of NH3. Herein, dopamine hydrochloride was selected as a N doping source to in-situ polymerization on the Ti3C2Tx MXenes surface forming a highly efficient co-catalyst, and then integrated into BiOBr to induce a super high photocatalysis for ammonia synthesis. As expected, BiOBr was evenly dispersed on the N-Ti3C2Tx MXene surface. The photocatalysis possessed a high degree of photocatalytic ammonia evolution (270.73 μmol/g·h and 3.27 times higher than that of BiOBr) and retained about 60 % of its ammonia evolution after five consecutive cycles. The photocatalyst mechanism is high dispersion and elevated conduction band potential of N-Ti3C2Tx MXene nanosheets facilitated charge transfer to the active sites of the nanosheets. This study proved the potential use of dopamine hydrochloride in MXene photocatalytic materials for solar energy utilization ammonia synthesis.