Tuning near-gap electronic structure, interface charge transfer and visible light response of hybrid doped graphene and Ag3PO4 composite: Dopant effects

Abstract

The enhanced photocatalytic performance of doped graphene (GR)/semiconductor nanocomposites have recently been widely observed, but an understanding of the underlying mechanisms behind it is still out of reach. As a model system to study the dopant effects, we investigate the electronic structures and optical properties of doped GR/Ag3PO4 nanocomposites using the first-principles calculations, demonstrating that the band gap, near-gap electronic structure and interface charge transfer of the doped GR/Ag3PO4(100) composite can be tuned by the dopants. Interestingly, the doping atom and C atoms bonded to dopant become active sites for photocatalysis because they are positively or negatively charged due to the charge redistribution caused by interaction. The dopants can enhance the visible light absorption and photoinduced electron transfer. We propose that the N atom may be one of the most appropriate dopants for the GR/Ag3PO4 photocatalyst. This work can rationalize the available experimental results about N-doped GR-semiconductor composites, and enriches our understanding on the dopant effects in the doped GR-based composites for developing high-performance photocatalysts.

Carbon-Based Materials for Electrochemical Reduction of CO2 to C2+ Oxygenates: Recent Progress and Remaining Challenges

“…An approach to tune the electronic structure of catalysts is incorporation of heteroatom, especially for carbon-based materials. Generally, different dopants (B, N, P, and F) possess various electronegativities, which are different from the electronegativity of carbon atoms, thus breaking electroneutral carbon networks and inducing redistribution of electrons (Figure a–d). , The most common dopant heteroatoms for improving CO 2 reduction activity is N atoms . The N dopant can be classified into quaternary N, pyridinic N, pyrrolic N, and oxidized N species (Figure e).…”

Charge transfer of carbon nanomaterials for efficient metal‐free electrocatalysis

“…[ 57 ] To get a comparative view, the Mulliken electron population on N‐, S‐, B‐, and P‐doped graphene has been presented in Figure 3. [ 58 ] Unlike B, N, and P doping, there exists a negligible charge transfer in S‐doped graphene lattice because of the similar electronegativities of S (∼2.58) and C (∼2.55) atoms. [ 59 ] However, in contrast to the zero electronic spin density of the pristine graphene lattice, the mismatch of the outermost orbitals of S and C atoms introduces a nonuniform electronic spin density distribution on the S‐doped graphene with a large S–C bond length (∼1.78 Å), which in‐turn provides active catalytic functionalities to graphene useful for energy conversion applications, including ORR.…”

Silver Phosphate/Graphene Oxide Aerogel Microspheres with Radially Oriented Microchannels for Highly Efficient and Continuous Removal of Pollutants from Wastewaters

“…Although silver phosphate (Ag 3 PO 4 ) has a highly efficient visible light catalytic activity, its small specific surface area and easy photocorrosion in the absence of a sacrificial agent limit its wide application in the environmental field. − Because GO is an effective acceptor of photoexcited electrons, the combination of Ag 3 PO 4 with GO aerogels would efficiently prevent the photocorrosion of Ag 3 PO 4 by accelerating charge transfer. Thus, in the present work, by utilizing ice templates, the radially diverged internal microchannels are formed in the GO-based aerogel microspheres, which not only possess high specific surface area to enhance the adsorption of pollutants but also favor the fast adsorption equilibrium by shortening the diffusion pathway for pollutants entering into the porous aerogel microspheres.…”