Breaking the Limits of Piezo‐Photocatalysis: Pd‐O d‐p Orbital Hybridization Mediated Charge Reconstruction and Polarization Enhancement

ABSTRACT

Piezo‐photocatalysis has emerged as a promising strategy to suppress charge recombination in conventional photocatalysis for the removal of refractory organic pollutants and green hydrogen peroxide (H ₂ O ₂ ) production. Nevertheless, sulfide‐based piezo‐photocatalysts still suffer from weak piezoelectric response and ambiguous coupling mechanisms between atomic orbitals and polarization. Herein, we designed Pd‐doped and lattice oxygen‐modified Zn ₃ In ₂ S ₆ piezo‐photocatalyst (Zn ₃ In ₂ S ₆ ‐Pd‐350) by regulating d‐p orbital hybridization at Pd sites to achieve efficient piezo‐photocatalytic performance. Lattice oxygen occupies sulfur vacancies and converts Pd–S into Pd–O coordination, enabling strong Pd 4d–O 2p orbital hybridization. The σ* and π* antibonding orbitals act as electron acceptors to accelerate charge separation. The charge asymmetry induced by Pd and lattice oxygen enhanced piezoelectric properties of catalyst, resulting in a 156% increase of the piezoelectric coefficient. Zn ₃ In ₂ S ₆ ‐Pd‐350 achieved 100% degradation of 2,4‐DCP and H ₂ O ₂ yield of 327.9 µmol·g ⁻¹ ·h ⁻¹ , accompanied by •OH, •O ₂ ⁻ and ¹ O ₂ synergistic oxidation. Calculations confirm that single‐atom Pd replacing Zn is the active center with optimal Pd–S ₁ O ₃ coordination, and external strain further enhances O ₂ /H ₂ O adsorption. This work establishes an atomic‐level design strategy via orbital engineering, reveals the essential synergy among orbital hybridization, charge distribution and piezoelectric polarization, and provides a feasible route for chlorophenol wastewater remediation and low‐carbon H ₂ O ₂ synthesis.