Spin polarization-coupled piezocatalysis in Fe-doped Bi3TiNbO9: Synchronous kinetic and thermodynamic optimization for superior H2O2 production

Regulation of electron spin polarization (SP) has been demonstrated to significantly influence the reaction rates and pathways of diverse catalytic reactions. However, the application of SP in piezocatalysis and its underlying mechanisms remain poorly understood. In this study, we design a Fe-doped Bi 3 TiNbO 9 piezoelectric semiconductor to synergistically integrate SP and piezocatalysis, optimizing both the kinetics and thermodynamics of H 2 O 2 production. Structural analyses reveal that Fe incorporation enhances the piezoelectric response through inducing off-centering displacement of [TiO 6 ]/[NbO 6 ] octahedra. Crucially, the combination of intrinsic SP form Fe dopants and magnetically enhanced SP substantially improves carrier mobility. Density functional theory calculations further verify that SP greatly reduces the Gibbs free energy barrier for the direct one-step 2e − oxygen reduction reaction (ORR) pathway, successfully shifting the O 2 activation mechanism from the two-step 2e − ORR to the more efficient one-step 2e − ORR. The synergy of these effects enables Fe-doped Bi 3 TiNbO 9 to achieve an exceptional H 2 O 2 yield of 1421.2 μmol g −1  h −1 under mechanical stimulation and magnetic fields — a 10.4-fold enhancement over pristine Bi 3 TiNbO 9 . This work pioneers a new paradigm for mechanical-energy-driven green chemical synthesis by innovatively coupling piezoelectric effects with spintronics.