An antimonene/Cp*Rh(phen)Cl/black phosphorus hybrid nanosheet-based Z-scheme artificial photosynthesis for enhanced photo/bio-catalytic CO2 reduction

Developing a biocatalyzed artificial photosynthesis system (APS) with a Z-scheme for CO2 conversion has a promising outlook. However, it remains unexplored and challenging. Herein, we present an antimonene (AM) and black phosphorus (BP) hybrid nanosheet (HNSs) based Z-scheme APS for enhanced photo/bio-catalytic CO2 reduction. An "amphipathic" polymer PEI-PEG-C18 with a positively charged PEI-head and hydrophobic C18-tail was synthesized and further modified with an electron mediator (M, Cp*Rh(phen)Cl). Using this PEI-PEG-C18-M as a "double-side tap", AM/M/BP HNS-based Z-scheme photocatalytic systems were constructed through catenating AM NSs via a hydrophobic interaction with the hydrophobic C18-tail and subsequent BP NSs via electrostatic interactions with the positively charged PEI-head. Thereafter, the biocatalytic system, including NAD(H)(+) and redox enzymes, were sandwiched between the AM and BP layers through an electrostatic attraction with the amide groups in the "double-side tap". Due to the high separation efficiency of the photogenerated electrons and holes and the improved reduction and oxidation potentials, the integrated Z-scheme APS shows excellent performance. In particular, although neither AM nor BP could catalyze NADH regeneration using H2O as an electron donor under visible light, a 35 +/- 4% regeneration of NADH and 160 +/- 24 mu mol formic acid production were achieved by the AM/M/BP HNS-based Z-scheme APS. Moreover, the compatibility and omnipotence of the HNS-based APS for the synthesis of other high value-added products from CO2 have been demonstrated through assembling the corresponding biocatalysts.