Band alignment in Zn₂SnO₄/SnO₂ heterostructure enabling efficient CO₂ electrochemical reduction

Engineering heterojunction is an underlying strategy to develop remarkable electrocatalysts for carbon dioxide (CO₂) reduction due to its ability to tune electronic properties by interfacial cooperation. Herein, we report a novel type of cube-like Zn₂SnO₄/SnO₂ heterostructure catalyst for CO₂ reduction through a simple co-precipitation process. The high-quality heterostructures with band alignment promote interfacial charge transfer from Zn₂SnO₄ to SnO₂, achieving the electronic modulation of  Zn₂SnO₄/SnO₂ for reducing the kinetic barriers of CO₂ reduction. Density functional theory further reveals that  Zn₂SnO₄/SnO₂ allows HCOO* intermediate favorably stabilizing on its surface through improved hydrogen coverage effect comparing to pure  Zn₂SnO₄ or SnO₂. The hybrid catalyst presents satisfactory CO₂ reduction properties with a stable HCOOH selectivity of 77% during 24 h at −1.08 V vs. RHE. This study provides a new heterostructure modeling and general methodology for electronic modulation and electrocatalysts development for high-performance CO₂ reduction.