Integration of interface engineering and La doping to boost two-electron oxygen reduction to hydrogen peroxide over La2Sn2O7@La-doped ZnSnO3 heterostructures

Abstract

Perovskite oxides have shown great potential application in fuel cells due to the unique crystal structures and tunable composition as well as effective capability toward the oxygen reduction reaction (ORR), whereas the investigation on the electrocatalytic performance of perovskite oxides toward the two-electron ORR to H₂O₂ production remains very limited. Herein, a facile synthetic method has been developed to prepare La₂Sn₂O₇@La-doped ZnSnO₃ heterostructures comprising of amorphous La₂Sn₂O₇ and crystalline La-doped ZnSnO₃. The optimal La₂Sn₂O₇@La-doped ZnSnO₃ heterostructures catalyst exhibits a significantly improved two-electron ORR performance to H₂O₂ production with onset potential of 0.77 V and large current density of 2.51 mA·cm⁻² at 0.1 V compared to ZnSnO₃ (0.75 V, 1.80 mA·cm⁻², 0.11 mA) as well as maintains high H₂O₂ selectivity of 80%, which has been theoretically demonstrated to be contributed to the synergistic effect of amorphous La₂Sn₂O₇ and crystalline La-doped ZnSnO₃. Moreover, high H₂O₂ yield rate of 2.9 mM·h⁻¹ at 0.1 V can be achieved with a superior turnover frequency (TOF) of 3.31 × 10⁻² s⁻¹ compared to the ZnSnO₃ catalyst (2.10 × 10⁻² s⁻¹). This work reveals the great potential of perovskite oxide as promising candidates for the environmentally friendly synthesis of hydrogen peroxide.

Graphical abstract

Perovskite oxide-based La-doped ZnSnO₃ (La₂Sn₂O₇@La-doped ZnSnO₃) heterostructures were prepared as a high-efficient electrocatalyst, delivering a high H₂O₂ yield rate of 2.9 mmol·L⁻¹·h⁻¹ at 0.1 V.