Enzymatic synthesis of supported CdS quantum dot/reduced graphene oxide photocatalysts

Abstract

Biomineralization provides a route towards scalable, aqueous phase synthesis of heterostructured photocatalysts for solar driven hydrogen production.

Fast and efficient electrical–thermal responses of functional nanoparticle decorated nanocarbon aerogels

“…1g) for the rGO aerogels indicates the formation of a large number of small-sized sp 2 hybridized domains within the structure. 20 Almost identical I D /I G ratios are observed for the MMO/rGO aerogel (I D /I G = 1.56) and BN/rGO aerogel (I D /I G = 1.54), suggesting that the decoration of NPs have no impact on the rGO sheets after thermal reduction (similar results for the rCNT aerogel, see Fig. S7).…”

Tailored Coupling of Biomineralized CdS Quantum Dots to rGO to Realize Ambient Aqueous Synthesis of a High-Performance Hydrogen Evolution Photocatalyst

“…26 Additionally, attempts to postsynthetically couple CdS/cys to rGO simply by lowering the pH fail due to the low pK a (1.96) of terminal carboxylic groups of Lcysteine, 27 which disfavors binding to the negatively charged rGO (Figure S1). Therefore, without addition of secondary macromolecular binders, 19 the efficient coupling of CdS to rGO in the aqueous phase and at ambient temperature requires replacement of the native surface-bound L-cysteine in favor of alternative capping agents that are capable of both stabilizing the nanocrystal in aqueous solution and binding the CdS nanocrystals to rGO. The electrostatic assembly is a simpler route to formation of the CdS/rGO heterostructure than through direct chemical binding, which would require introduction of carbodiimide coupling agents.…”

“…The CdS nanoparticles were found to have a diameter in the 2−4 nm range, which is consistent with the optical properties reported in Figure 1 and with our previously reported size distributions for the biomineralized CdS nanocrystals. 19,38,39 Low-magnification HAADF-STEM and high-angle annular bright-field (HAABF)-STEM clearly demonstrate that CdS is associated with rGO (Figure S3a−d). STEM images show that the distribution of CdS on rGO is not homogenous and that the particles are most likely attaching to both sides of the sheet.…”

“…20 While we have previously demonstrated the enzymatic synthesis of CdS nanocrystals and rGO in the development of a CdS/rGO photocatalyst, the efficiency and hydrogen production rates of this photocatalyst were far below their chemically synthesized counterparts, likely owing, at least in part, to poor interfacial connectivity between rGO and the semiconductor nanocrystals. 19 The components of the chemically synthesized heterostructured photocatalysts are typically annealed together or grown simultaneously at elevated temperatures, forming strong attachment between the constituents. Low-temperature synthesis routes must rely on other means of attachment.…”

Ultrasensitive Detection of Tetracycline Using Boron and Nitrogen Co-Doped Graphene Quantum Dots from Natural Carbon Source as the Paper-Based Nanosensing Probe in Difference Matrices

“…The synthesis of nanomaterials such as silver [ 4 ], gold [ 5 ], magnetic nanoparticles [ 6 ], V 2 O 5 [ 7 ], organic-metal frameworks [ 8 ] and inorganic quantum dots [ 9 ] for biological applications has recently received increasing interest. Moreover, carbon dots (CDs) synthesized from natural carbon sources such as fruit juice [ 10 ], pine wood [ 11 ], vegetable [ 12 ], grass [ 13 ] and tobacco [ 14 ] has been reported to exhibit an excellent optical property for the bio-imaging of microorganisms as well as for the detection of chemicals.…”