Experimental and DFT Insights on Microflower g-C₃N₄/BiVO₄ Photocatalyst for Enhanced Photoelectrochemical Hydrogen Generation from Lake Water

Abstract

Herein, an experimental and density functional theory (DFT) analysis of the composite g-C 3 N 4 /BiVO 4 microflower photocatalysts are comprehensively discussed. A remarkable photoelectrocatalytic solar hydrogen production has been observed for the as-developed photocatalysts, with different loading amounts of g-C 3 N 4 (0.1, 0.4, 0.8, and 1.2 wt %), using lake water without the addition of sacrificial reagents. The 0.8 wt % g-C 3 N 4 /BiVO 4 microflower photocatalyst evinced remarkable photoelectrocatalytic activity of 21.4 mmol/h of hydrogen generated in comparison to other samples with an AQE of 4.27% at 420 nm. In addition, the photocurrent density of 0.8 wt % g-C 3 N 4 /BiVO 4 microflower was 2fold higher than that of pure BiVO 4 . This was attributed to its better crystallinity and optical properties, confirmed from XRD and DR-UV−vis analysis. The DFT analysis further corroborated that the efficient photocharge carrier separation and limited photocharge carrier recombination corresponded to the synergistic effect of the band offset and built-in electric field.

Modulating Local Charge Distribution of Carbon Nitride for Promoting Exciton Dissociation and Charge‐Induced Reactions

“…Many effective strategies have been developed in this direction, such as constructing heterojunctions and hybridizing carbon nitride with different structure. [ 30,31 ] Lu and co‐workers introduced BiOBr with oxygen vacancies into carbon nitride. [ 32 ] The oxygen vacancies in BiOBr can trap electrons and effectively reduce electron–hole recombination.…”

Superior photoelectrocatalytic performance of ternary structural BiVO4/GQD/g-C3N4 heterojunction

“…Generally, the pure BiVO4 and g-C3N4 were individually prepared via a modified hydrothermal method and thermal polycondensation of urea, respectively. The details of these synthesizing protocols can be found 6 elsewhere [7]. Meanwhile, the RGO was synthesized using a modified Hummer's method reported by Samsudin et al [17] and GQDs were prepared according to the previously reported literature [20].…”

“…Meanwhile, the tetragonal structure was made up of only O 2p orbitals, consequently, lengthen the transition of the photocharge carrier which can promote the recombination rate and limits the photocatalytic performance. Nevertheless, there are several bottleneck issues of the pure BiVO4 which has hindered the overall practicality of this semiconductor material [7,8].…”

Activation Strategy of WS2 as an Efficient Photocatalytic Hydrogen Evolution Cocatalyst through Co2+ Doping to Adjust the Highly Exposed Active (100) Facet

“…[ 65 ] The charge distribution in WS 2 is uniform, which is attributed to the high spatial symmetry of its 2D nanosheets structure, and the charge is difficult to transfer between layers because of the van der Waals forces inhibit further transfer of photoelectric charges. In contrast, due to the doping of Co 2+ on the (100) crystal plane of WS 2 that the defective energy level is generated and promoted the secondary migration of charge to Co 2+ , the charge density in the (100) crystal plane of Co–WS 2 has significant change, which manifests that the reduction process occur on the interface of Co–WS 2 , [ 66 ] respectively. This shows that after the element doping, the intrinsic symmetry structure of the WS 2 2D material was broken, and the surface is formed an electron transfer channel.…”