Title: Effect of Controlled Oxygen Vacancy on H2‐Production through the Piezocatalysis and Piezophototronics of Ferroelectric R3C ZnSnO3 Nanowires
Abstract: This study is the first to demonstrate that ferroelectric R3c LiNbO3‐type ZnSnO3 nanowires (NWs), through the piezocatalysis and piezophototronic process, demonstrate a highly efficient hydrogen evolution reaction (HER). The polarization and electric field curves indicate that ZnSnO3 NWs exhibit typical ferroelectric hysteresis loops. Time‐resolved photoluminescence spectra reveal that the relaxation time increases with the increasing concentration of oxygen vacancies. Moderated 3H‐ZnSnO3 NWs (thermally annealed for 3 h in a hydrogen environment) have the longest extended carrier lifetime of approximately 8.3 ns. The piezoelectricity‐induced HER, via the piezocatalysis process (without light irradiation), reaches an optimal H2‐production rate of approximately 3453.1 µmol g−1 h−1. Through the synergistic piezophototronic process, the HER reaches approximately 6000 µmol g−1 in 7 h. Crucially, the mechanical force–induced spontaneous polarization functions as a carrier separator, driving the electron and hole in opposite directions in ferroelectric ZnSnO3 NWs; this separation reduces the recombination rate, enhancing the redox process. This theoretical analysis indicates that the photocatalytic and piezocatalytic effects can synergistically enhance piezophototronic performance through capitalizing on well‐modulated oxygen vacancies in ferroelectric semiconductors. This study demonstrates the essential role of this synergy in purifying water pollutants and converting water into hydrogen gas through the piezophototronic process.