Amphiphilic heterojunctions with atomically dispersed copper–alkynyl active units for highly efficient CO2 photoreduction

The efficiency of CO photoreduction is limited by slow charge kinetics and the mass transfer of hydrophobic CO and HO over the photocatalyst. Herein, we present a copper–alkynyl bond coordination polymer (CA-CP) with atomically-dispersed copper–alkynyl units (ADCAUs). By incorporating hydrophobic CA-CP with hydrophilic iodine vacancy-rich bismuth oxyhalides (I-BX), we construct amphiphilic heterojunction photocatalysts (CA-CP/I-BX) for visible-light-driven CO photoreduction. CA-CP/I-BX achieves excellent stability, 100 % CO selectivity and a CO-evolution rate of 157.6 μmol g h coupled with O releasing. Experimental and theoretical calculations elucidate that the ADCAUs favor adsorption and activation of CO, and have high CO selectivity. Moreover, the amphiphilic janus structure not only ensures the spatial synergy effect of CO reduction and HO oxidation, but also promotes charge separation and proton feeding, boosting CO photoreduction activity. This work develops Cu–alkynyl coordination polymer photocatalysts with ADCAUs and provides insights into hydrophobic–hydrophilic biphasic photocatalysts for synergistic CO reduction and HO oxidation.