CuBi₂O₄ Based Hybrid Photocathodes for Enhancement of the Photoelectrochemical Reduction of CO₂

Abstract

Photoelectrochemical (PEC) CO 2 reduction reaction (CO 2 RR) is a promising strategy to mitigate energy shortage and global warming by conversion of CO 2 into chemical fuels. CuBi 2 O 4 (CBO) is an attractive p-type photoelectrode, because it has a suitable band gap (1.5 to 1.8 eV) for visible light absorption and band edge position for PEC CO 2 RR. Furthermore, Cu-based catalysts can convert CO 2 into multi-carbon products. However, the photoconversion efficiency of CBO is limited by short carrier diffusion length and poor photostability. In this work, we fabricated hydrothermal CBO based hybrid photocathode. The hydrothermal CBO/cellulose nano fibers (CNFs) composites with a large surface area and a porous network structure were prepared to achieve higher photocurrent density, in which CNFs are an abundant, non-toxic, and eco-friendly polymer, offering a porous and flexible network structure as a template during hydrothermal treatment. To enhance the PEC CO 2 RR, we introduce the ultrathin TiO 2 a passivation layer deposited by atomic layer deposition (ALD) and NiO as a hole transport layer (HTL) to increase charge transport efficiency. Therefore, we will discuss enhanced performance and stability by introducing these improvement methods.