Nitrogen‐Doped Graphene Quantum Dot‐Decorated ZnO Nanorods for Improved Electrochemical Solar Energy Conversion

Abstract

Nitrogen‐doped graphene quantum dots (N‐GQDs) have been synthesized using a hydrothermal process. The N‐GQDs are highly crystalline with a size of 3–7 nm and made up of 1–3 layers of graphene. UV/Vis absorption studies reveal two major absorption peaks at 237 and 334 nm, which are attributed to the π→π* transition of C=C and n→π* transition of C=O bonds, respectively. The additional broad peak observed at 460–500 nm is attributed to the n→π* transition of C=N bonds. The N‐GQDs are highly luminescent and exhibit excitation‐dependent emission. The photoelectrochemical properties of pristine ZnO and N‐GQD‐sensitized ZnO nanorods have been investigated. N‐GQD‐sensitized nanorod photoanodes demonstrate superior photoconversion efficiency, incident photon‐to‐current conversion efficiency, and power conversion efficiency compared with pristine ZnO nanorods.

Growth of Carbon‐Functionalized, Carbon‐Doped ZnO/C Core‐Shell Nanorods for Photoelectrochemical Solar Energy Conversion

“…Figure (b) shows the variation of photoconversion efficiency (i. e. photon to hydrogen) as a function of external bias vs. Ag/AgCl for all photoanodes. The photoconversion efficiencies were calculated using the following equation, …”

“…NGQDs were synthesized using hydrothermal method. The detail growth and characterization have been discussed elsewhere . The schematic diagram of a typical QDSSC device is presented in Figure (a).…”

Graphene quantum dots as a green photosensitizer with carbon-doped ZnO nanorods for quantum-dot-sensitized solar cell applications

“…All GQDs were synthesized by a hydrothermal process [13][14][15]. ZnO NRs were grown on FTO-coated glass substrates by a two-step chemical process.…”

Biomass‐Derived N‐doped Carbon Materials with Silica‐Supported Ultrasmall ZnO Nanoparticles: Robust Catalysts for the Green Synthesis of Benzimidazoles

“…[6,33] The deconvolution of N1senergy-level signals ( Figure 6d)s uggests that ZnO/SiO 2 -NC-600 contains several nitrogen species, including intact NH 2 groups (397.74 eV); pyridinic,p yrrolic,a nd graphitic nitrogen atoms (398.73, 399.72, and 400.70 eV,respectively), and pyridinic N-oxide functions (402.01 eV). [6,[34][35][36] In addition, an N1 ss ignal also appears at 398.13 eV,w hich falls in the range of the binding energies of NÀZn bonds, thus further verifying that interactions be- tween ZnO nanoparticlesa nd the N-doped carbon support exist. [24,37] The scope of applicability of the ZnO/SiO 2 -NC-600 catalyst was explored for the synthesis of 2-arylbenzimidazoles by using various aromatic aldehydesa nd diamines in methanol.…”