Stand-Alone CdS Nanocrystals for Photocatalytic CO2 Reduction with High Efficiency and Selectivity.

The development of a cost-effective photocatalyst is highly anticipated to achieve efficient photocatalytic CO2 reduction with superior selectivity, which is still facing the lack of valid settlements. Herein, 4-mercaptopyridine (PD) as the building block of a capping ligand is tightly decorated on the surface of CdS nanocrystals (CdS-PD) using a facile ligand-exchange strategy, to exploit a cost-effective photocatalyst for photocatalytic CO2 reduction without any cocatalysts. The conjugated structure of PD can facilitate the delocalization of photogenerated electrons in CdS nanocrystals, bringing forth an improved charge separation efficiency. More importantly, N-protonated PD can enable the easy formation of a six-membered ring intermediate with CO2 assisted by water, which can serve as the efficient active site to achieve photocatalytic CO2 reduction. In the absence of a cocatalyst, stand-alone CdS-PD nanocrystals exhibit an excellent CO yield of 20.35 mmol g-1 h-1 concomitant with a high selectivity of 95.3% for the CO2-to-CO conversion under visible light, which are remarkably superior than those of CdS nanocrystals possessing traditional alkyl-chain and other conjugated capping ligands.

Glycine-Functionalized CsPbBr3 Nanocrystals for Efficient Visible-Light Photocatalysis of CO2 Reduction.

Capping ligands are indispensable for the preparation of metal-halide-perovskite (MHP) nanocrystals (NCs) with good stability; however, the long alkyl-chain capping ligands in conventional MHP NCs will be unfavorable for CO2 adsorption and hinder the efficient carrier separation on the surface of MHP NCs, leading to inferior catalytic activity in artificial photosynthesis. Herein, CsPbBr3 nanocrystals with short-chain glycine as ligand are constructed through a facile ligand-exchange strategy. Owing to the reduced hindrance of glycine and the presence of the amine group in glycine, the photogenerated carrier separation and CO2 uptake capacity are noticeably improved without compromising the stability of the MHP NCs. The CsPbBr3 nanocrystals with glycine ligands exhibit a significantly increased yield of 27.7 µmol g-1 h-1 for photocatalytic CO2 -to-CO conversion without any organic sacrificial reagents, which is over five times higher than that of control CsPbBr3 NCs with conventional long alkyl-chain capping ligands.

Synergetic catalysis of a cobalt-based coordination polymer for selective visible-light driven CO2-to-CO conversion.

Herein, based on the strategy of synergetic catalysis, we report a cobalt-based coordination polymer PEI6-Co. As a heterogeneous catalyst, PEI6-Co shows a selectivity of 95% and a yield of 1170 mmol g-1 for visible-light-driven CO2-to-CO conversion in a water containing system, which is almost 2.8 times that of the mononuclear cobalt catalyst CoL1 and is comparable to that of the dinuclear cobalt catalyst Co2L.