Controlled Construction of Copper Phthalocyanine/α‐Fe2O3 Ultrathin S‐Scheme Heterojunctions for Efficient Photocatalytic CO2 Reduction under Wide Visible‐Light Irradiation

Abstract

The wide visible‐light‐driven CO2 reduction to acquire solar fuels is a highly desired green route. Herein, novel ultrathin copper phthalocyanine (CuPc)/α‐Fe2O3 heterojunctions as efficient wide visible‐light‐driven photocatalysts for CO2 reduction are controllably synthesized by the hydroxyl‐induced self‐assembly of CuPc onto ultrathin α‐Fe2O3 as‐pre‐prepared through an Al3+‐regulated hydrothermal method. The optimized CuPc/Fe2O3 heterojunction exhibits about 15‐fold high photoactivity for reducing CO2 to CO and CH4 compared with reported Fe2O3 nanoparticles. The exceptional photoactivity is mainly attributed to the enhanced S‐scheme charge transfer and separation in the resulting closely contacted heterojunction, the extended visible‐light range from molecularly disperse CuPc, and its provided central metal cation (Cu2+) with favorable catalytic function for CO2 activation, mainly by means of the dual‐wavelength photocurrent action spectra, the electrochemical reduction tests, and the in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS). This investigation provides new insight about designing and constructing novel metal phthalocyanine (MPc)‐involved S‐scheme heterojunction photocatalysts.

Keywords

• CO2 reduction
• copper phthalocyanine assembly
• S-scheme charge transfer
• ultrathin α-Fe2O3
• wide visible-light photocatalysis