Enhancing the Photocatalytic Hydrogen Evolution of ZnCdS through Induced Dipole Polarization
Jiaxin Liu, Guangmin Ren, Guojing Hu, Chengwei Wang, Tuo Guo, Qingjie Guo, Pei Sean Goh
Abstract
Photocatalytic hydrogen evolution reaction (HER) faces challenges due to inefficient charge transfer, limited active sites, and water activation difficulties. Effective manipulation of the dipole polarization electric field offers a solution to overcome these obstacles. Herein, the introduction of highly electronegative element N into the ZnCdS (ZCS) structure increased the dipole moment from 2.58 to 3.35 eÅ via a one-step solvothermal method. The increased dipole moment generates a spontaneous polarization field within the photocatalyst, promoting directed charge migration and enhancing H 2 evolution efficiency. Through a combination of comprehensive experimental and theoretical analyses, we confirm that the introduction of N induces a dipole polarization electric field in ZCS, decreases the distance between H 2 O and the active site N, and reduces the HER energy barrier. Consequently, the best performing catalyst ZCS-TETA-8 demonstrates significantly improved activity of 115.7 mmol/g/h and maintains stability over 5 cycles. This work provides a new strategy for developing efficient HER catalysts.