Multipoint-bridging structure with a piezoelectricity-induced S-scheme junction for piezoelectricity-enhanced photoelectrochemical H2O2 production

Abstract

The construction of efficient heterojunctions can significantly facilitate the rapid separation and transfer of photogenerated charges, but the formation of an S-scheme homojunction induced by external electric fields has not been reported. Herein, a vertically aligned Sb-doped p-type CdS nanowire (p-CdS_NW) array was hydrothermally synthesized on an ITO electrode, followed by the end-capping agent-assisted photodeposition of transverse Au nanorods (Au_NR) to multipoint-bridge the p-CdS_NW to yield a novel Au_NR/p-CdS_NW/ITO photocathode with a multipoint bridging structure for piezoelectricity-enhanced photoelectrochemical (PPEC) H₂O₂ production. The Au_NR/p-CdS_NW/ITO photocathode gave a PPEC photocurrent density of −6.34 mA cm⁻², significantly higher than that of the electrode without stirring (−2.85 mA cm⁻²) and an Au nanoparticles/p-CdS_NW/ITO electrode without Au-bridging (−3.36 mA cm⁻²). The excellent PPEC performance is explained mainly by the transverse piezoelectric field generated by the piezoelectric effect, which bends the bands of adjacent p-CdS_NW at both ends of the Au_NR to form interlaced energy band positions and electrostatic attraction, meeting the three essential elements of S-scheme heterojunctions, thus forming a novel piezoelectricity-induced S-scheme p-CdS_NW/Au_NR/p-CdS_NW junction, which may contribute to the innovation and application of high-performance PPEC materials.