Enhanced Photocatalytic CO <sub>2</sub> Reduction over Ni-doped Bi <sub>4</sub> O <sub>5</sub> Br <sub>2</sub> /NiCo <sub>2</sub> O <sub>4</sub> Heterojunction: Synergistic Enhancement Effect between Spin Polarization and Built-in Electric Field
Zhixiong Yang, Bo Hu, Xiaotian Wang, Dmitry Selishchev, Gaoke Zhang
Abstract
The development of high-performance photocatalysts is crucial for enabling efficient CO 2 conversion in photocatalytic systems. Here, we developed a novel heterojunction (N-BON) composed of Ni-doped Bi 4 O 5 Br 2 and NiCo 2 O 4 for CO 2 photoreduction with the help of simulated sunlight. The optimized 21N-BON composite exhibited the highest activity, producing 18.66 μmol·g –1 ·h –1 of CO with a selectivity of 95.7%, which represents a remarkable 2.15-fold and 4.75-fold increase in CO yield compared to the Bi 4 O 5 Br 2 /NiCo 2 O 4 heterojunction and Ni-doped Bi 4 O 5 Br 2, respectively. Photoelectrochemical testing, photoluminescence analysis, and theoretical calculations demonstrated that the enhanced performance of the 21N-BON composite is attributed to improved photogenerated carrier separation, driven by the synergistic effects of Ni-doping-induced spin polarization and the built-in electric field from heterojunction construction. Additionally, theoretical calculations and in situ DRIFTS analyses was used to clarify the CO 2 reaction mechanisms on the photocatalyst surface, showing that Ni doping improved CO 2 adsorption and promoted the formation of key reaction intermediates. This study offers important guidance for developing advanced photocatalysts for solar-driven CO 2 reduction, contributing to sustainable energy solutions.