Photoinduced deposition of AuCu cocatalyst and polyaniline conducting layer on graphitic-C3N4 for enhanced CO2 photoreduction

Abstract

Photocatalytic CO2 conversion into solar fuel is of great significance for addressing energy crisis and climate change, but this process is generally hampered by insufficient electron deliverability and sluggish reaction kinetics. Herein, polyaniline (PANI) conducting layer and AuCu alloy cocatalyst are successively deposited on graphitic carbon nitride (g-C3N4) nanoflakes via a two-step photoinduced process, to fabricate an AuCu/PANI/g-C3N4 heterostructure photocatalyst. The presence of PANI layer improves electron deliverability and CO2 adsorption capacity of photocatalyst. The AuCu cocatalyst affords efficient active sites for accelerating the reaction kinetics of CO2 photoreduction, and the surface plasmon resonance (SPR) of Au further enhances light utilization and charge separation. Benefiting from these merits, the AuCu/PANI/g-C3N4 photocatalyst exhibits a superior performance toward CO2 reduction with 100% CO selectivity, affording a CO production rate of 9.2 μmol·gcat−1·h−1 under simulated sunlight, which is 1.3 times that from AuCu/g-C3N4 and 2.3 times that from PANI/g-C3N4, respectively. The photocatalytic CO2 reduction mechanism of AuCu/PANI/g-C3N4 catalyst is investigated by a series of control experiments and in-situ infrared spectroscopy. This study demonstrates a rational construction of heterogeneous photocatalysts and highlights the synergistic effect of multiple components in enhancing CO2 photoreduction.