Piezotronic Effect Enhanced Plasmonic Photocatalysis by AuNPs/BaTiO₃ Heterostructures

Abstract

Piezopotential-assisted catalysis is of great significance for low cost and efficient catalysis processes. Here, Au x /BaTiO 3 plasmonic photocatalysts are fabricated by precipitating Au nanoparticles on piezoelectric BaTiO 3 nanocubes through a chemical approach. The Au nanoparticles (<8 nm) are decorated uniformly on the surface of BaTiO 3 , which endows the heterostructure with a wide light absorption from 300 to 600 nm. The photocatalytic properties of the heterostructures are investigated in detail toward methyl orange (MO) degradation. The Au content, piezoelectric potential of the BaTiO 3 substrate, and surface plasmon resonance (SPR) are confirmed to be vital to the photocatalytic activity. The Au 4 /BaTiO 3 shows an optimum photocatalytic performance for a complete degradation of MO in 75 min under full spectrum light irradiation with auxiliary ultrasonic excitation. The piezoelectric field originating from the deformation of BaTiO 3 further enhances the separation of photon-generated carriers induced by SPR and promotes the formation of hydroxyl radicals, which results in a strong oxidizing ability of organic dyes. This work introduces the piezotronic effect to enhance plasmonic photocatalysis with Au x /BaTiO 3 heterostructures, which is ready to extend to other catalytic systems and offers a new option to design high-performance catalysts for pollutant treatment.

Advances in Piezo‐Phototronic Effect Enhanced Photocatalysis and Photoelectrocatalysis

“…Some researchers focused on the interaction of BaTiO 3 and metals or electrocatalysts, such as Al, Au, Ag, etc., [ 106,111–113 ] and further clarified the mechanism of the coupling effect between piezotronics and surface plasmonic resonance. [ 33 ] For example, Xu et al reported Ag–BaTiO 3 piezo‐photocatalysts synthesized by a photochemical reducing approach.…”

“…By introducing Au nanoparticles, the visible‐light‐driven catalytic degradation of methyl orange by BaTiO 3 was much enhanced. [ 112 ] The cooperation of BaTiO 3 with other semiconductors such as ZnO/BaTiO 3 heterostructure has also been demonstrated to work well in the degradation of pollutants, which endows a suitable bend alignment formed at the interface to promote charge transfer behavior. [ 114 ]…”

“…[ 115 ] In another work, Xu et al used Au/BaTiO 3 nanostructures to illustrate the piezo‐enhanced plasmonic degradation mechanism. [ 112 ] As shown in Figure 19b, when Au is in contact with BaTiO 3 , a Schottky barrier is formed at the interface due to their work function difference (left panel). Under light illumination, the surface electrons of Au exhibit collective oscillations localized surface plasmon resonance (LSPR) and decay into energetic hot electrons.…”

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“…To attest the ferroelectric property of BTO, the sample's XRD was checked ( Figure S7, Supporting Information), which describes that the phase of BTO has been changed from cubic to tetragonal (presence of ferroelectricity) by the splitting peaks. [39] From the TEM image, the size of annealed BTO is found to be 50 nm with a d-spacing of 0.231 nm attributed to (111) crystal plane (Figure 2e). Moreover, the selected area electron diffraction image makes known that the main crystal planes of BTO are (100), (110), (111), (211), and (320) (Figure 2f), but the (200) plane exhibits a tiny scattering, revealing that the crystal plane spacing is split and matched well with the XRD data.…”

“…To attest the ferroelectric property of BTO, the sample's XRD was checked (Figure S7, Supporting Information), which describes that the phase of BTO has been changed from cubic to tetragonal (presence of ferroelectricity) by the splitting peaks . From the TEM image, the size of annealed BTO is found to be 50 nm with a d ‐spacing of 0.231 nm attributed to (111) crystal plane (Figure e).…”