Enhanced Piezo‐Photoelectric Catalysis with Oriented Carrier Migration in Asymmetric Au−ZnO Nanorod Array

Abstract

Current photocatalytic semiconductors often have low catalytic performance due to limited light utilization and fast charge carrier recombination. Formation of Schottky junction between semiconductors and plasmonic metals can broaden the light absorption and facilitate the photon‐generated carriers separation. To further amplify the catalytic performance, herein, an asymmetric gold‐zinc oxide (Asy‐Au−ZnO) nanorod array is rationally designed, which realizes the synergy of piezocatalysis and photocatalysis, as well as spatially oriented electron−hole pairs separation, generating a significantly enhanced catalytic performance. In addition to conventional properties from noble metal/semiconductor Schottky junction, the rationally designed heterostructure has several additional advantages: 1) The piezoelectric ZnO under light and mechanical stress can directly generate charge carriers; 2) the Schottky barrier can be reduced by ZnO piezopotential to enhance the injection efficiency of hot electrons from Au nanoparticles to ZnO; 3) the unique asymmetric nanorod array structure can achieve a spatially directed separation and migration of the photon‐generated carriers. When ultrasound and all‐spectrum light irradiation are exerted simultaneously, the Asy‐Au−ZnO reaches the highest catalytic efficiency of 95% in 75 min for dye degradation. It paves a new pathway for designing unique asymmetric nanostructures with the synergy of photocatalysis and piezocatalysis.

Piezocatalysis and Piezo‐Photocatalysis: Catalysts Classification and Modification Strategy, Reaction Mechanism, and Practical Application

“…The surface plasmon resonance (SPR) effect can endow the photocatalyst with intense light absorption, [42] and the schottky barrier at the metal-semiconductor contact can prevent the charge recombination. Under light irradiation, the SPR-induced hot charge carrier from Au will transfer to the semiconductors, like BaTiO 3 , [146] MoS 2 (Figure 16e) [147] and ZnO [148,149] due to the their work function difference. Piezo-potential of BaTiO 3 altered the charge distribution of nearby Au nanoparticles under ultrasonic (Figure 16a-c), resulting in a lower SBH.…”

Photothermal Structural Dynamics of Au Nanofurnace for In Situ Enhancement in Desorption and Ionization

“…[66,67] Therefore, the piezopotential was effectively generated across the extended ZNT crystal along the c-axis, and the Schottky barrier at the AuNI/ZNT interface was lowered. [68] These results reveal that the laser-induced restructuring/melting behavior occurring in the AuNI nanofurnace facilitated the alignment of electric dipoles in the ZNT along the c-axis and generated a piezoelectric field with the modulation of the Schottky barrier height, which possibly separated the photoinduced charge carriers and enhanced the ionization process in LDI-MS.…”

Photocatalysis Within Intrinsic Spontaneous Polarization Electric Field

“…Moreover, nonsymmetric Au/ZnO was constructed, which completed the efficient photocatalytic activity under ISPEF action, along with the effective spatial separation of electron–hole pairs. [ 31 ] Ag and graphene were also used to construct asymmetric ZnO‐based piezophotocatalysts. [ 32 ] In addition, a BaTiO 3 photocatalyst was considered as a typical piezoelectric polarization semiconductor, which could enhance the ISPEF by external force to deform crystal structure.…”