In-situ formation of Au nanoparticles with surface plasmon resonance confined in the framework of Cu ions doped NH2-MIL-125(Ti) to enhance photocatalytic hydrogen production and NO removal

Abstract

A novel bifunctional photocatalyst Au@NML-(Cu/Ti) was fabricated to improve the photocatalytic performance of hydrogen production and NO removal, in which the Cu ion was first doped into the titanium oxide clusters of NH2-MIL-125(Ti) (NML) via a convenient method, and uniformly dispersed gold nanoparticles with surface plasmon resonance effect in-situ generated under the constraint of NML-(Cu/Ti) framework. The introduction of copper ions reduced the band gap of NML and accelerated the charge separation rate. Moreover, the NML-(Cu/Ti) framework could prevent the Au nanoparticles agglomeration as far as possible via confinement effect to obtain highly dispersed gold nanoparticles in very small size, which can effectively improve the atom utilization efficiency for enhancing photocatalytic performance. The photocatalytic hydrogen production of Au@NML-(Cu/Ti) was 5193.4 μ mol·g−1, which was 11.8 times that of the original NML. Meanwhile, the NO removal rate of Au@NML-(Cu/Ti) was about 25.6% higher than that of the pristine NML. Moreover, the photocatalytic NO oxidation process was also monitored by in-situ DRIFTS, which indicates Au@NML-(Cu/Ti) could realize the effective oxidation of NO. These results showed that the synergistic combination of central metal cluster modification of MOFs with surface plasma resonance provided a feasible strategy for improving photocatalytic hydrogen production and NO removal.