Doping-reinforced interfacial electric field for charge oriented accumulation in Ohm junction boosting photocatalytic N₂ fixation

The interfacial electric field (IEF) determines the charge carriers transport and the reactivity of heterostructure photocatalyts. Nonetheless, the restricted IEF lead to inefficient interfacial charge transport and oriented accumulation, resulting in low photocatalytic efficiency. Herein, a interfacial chemical-bonded Ti-BiOBr/1T-MoS_1.85 Ohm junction is fabricated via electrostatic self-assembly strategy, in which Ti doping precisely regulates the local electrical structure and work function of BiOBr, thus boosting the IEF to efficiently drive charge transfer and oriented accumulation to active sites. The femtosecond transient absorption spectroscopy verified that the Ti_0.1Bi_0.9OBr/1T-MoS_1.85-6% increased the shallow electron trapping (τ₁ = 0.57 ps) while the depressed recombination of photoinduced electrons with trapped holes (τ₂ = 71.88 ps) compared to the BiOBr/1T-MoS_1.85-6% (τ₁ = 0.78 ps, τ₂ = 54.61 ps). More Importantly, the interfacial charge carriers transfer from Ti_0.1Bi_0.9OBr to 1T-MoS_1.85 (τ₃ = 86.53 ps) was significantly accelerated by the reinforced IEF compared to BiOBr/1T-MoS_1.85-6% (τ₃ = 221.51 ps). The N₂-to-NH₃ conversion rate of Ti_0.1Bi_0.9OBr/1T-MoS_1.85-6% Ohm junction (36.8 µmol g_cat⁻¹ h⁻¹) was 1.9 and 6.9-fold higher than that of BiOBr/1T-MoS_1.85-6% and 1T-MoS_1.85, respectively. This work provides a new insight into the design of Ohm junction with reinforced IEF for efficient interfacial charge carrier transfer and oriented accumulation towards efficient N₂ fixation.