P-Doped g-C₃N₄ Nanosheet-Modified BiVO₄ Hybrid Nanostructure as an Efficient Visible Light-Driven Water Splitting Photoanode

Abstract

Here, a solution combustion method was employed to construct a photoanode based on bismuth vanadate (BV) composition. To curtail the fast charge recombination, phosphorus-doped g-C 3 N 4 nanosheets (PCNS) in combination with BV are considered a potential approach. The prepared solution combustion facilitated the formation of a BiVO 4 -PCNS (BV-PCNS) hybrid photoanode with worm-like morphology with a simple setup. The weight ratio of PCNS/BiVO 4 and the loading volume/cm 2 were optimized to determine the most efficient photoanode. The highest photocurrent density of 0.5 mA/cm 2 at 1.23 V vs reversible hydrogen electrode (RHE) under 1 sun illumination was achieved for the hybrid nanostructure at 2 wt % of PCNS/BiVO 4 and 50 μL loading volume/cm 2 (BV-PCNS2-50), which is fivefold higher than that of the BV control sample. It was found that the presence of PCNS resulted in the formation of mid-gap states to enhance the visible light activity of BV-PCNS. A possible charge transfer mechanism is proposed under photoirradiation to show how the optimized deposition parameters influence the reduction of the electron−hole recombination rate of the photoanode and thus improve its photoelectrochemical water splitting performance. Density functional theory calculations were also performed to find the band alignment type formed across the BV/PCNS interface and to suggest the charge transfer mechanism in the BV/PCNS interface.

BiVO4 Heterojunctions as Efficient Photoanodes for Photoelectrochemical Water Oxidation

“…A solution combustion method was employed to construct a phosphorus‐doped g‐C 3 N 4 /BiVO 4 (PCNS/BiVO 4 ) photoanode by Mohazzab and co‐workers. The high photocurrent density could be ascribed to the presence of PCNS, providing larger carrier lifetime, highest charge carrier density, high surface area and construction of Type II alignment, which retard the electron‐hole recombination rate and decrease charge transfer resistance [13] . In addition, Wang et al.…”

“…The high photocurrent density could be ascribed to the presence of PCNS, providing larger carrier lifetime, highest charge carrier density, high surface area and construction of Type II alignment, which retard the electronhole recombination rate and decrease charge transfer resistance. [13] In addition, Wang et al designed the Type II heterojunction CdIn 2 S 4 /BiVO 4 to increase the photocurrent density from 1.22 (original BiVO 4 ) to 2.68 mA/cm 2 at 1.23 V. Compared with the reversible hydrogen electrode (RHE), the bulk separation of photoinduced carriers from the built-in field of the matching band was accelerated. With the introduction of CQD, the photocurrent density of CQD/CdIn 2 S 4 /BiVO 4 increased to 4.84 mA/cm 2 , which enhanced the light absorption and changed the initial potential of the cathode.…”

Direct Z-Scheme Heterostructure of In Situ Planted ZnO Nanorods on g-C3N4 Thin Sheets Sprayed on TiO2 Layer: A Strategy for Ternary-Photoanode Engineering toward Enhanced Photoelectrochemical Water Splitting

“…9 Despite its good stability even at high temperatures (up to 600 °C), 10 the low conductivity, small specific surface area, and rapid charge-hole recombination limit its widespread use in many photocatalytic processes. 11 Thus, several approaches have been employed to improve the photocatalytic activity of g-C 3 N 4 , such as doping with metal/nonmetal, 12 creating defects, 13 forming heterostructured composites, 14 and morphological engineering. 15 Among these approaches, combining g-C 3 N 4 with other photocatalysts to form heterojunctions has been particularly effective in enhancing the photocatalytic processes.…”

“…Moreover, g-C 3 N 4 can be a material for visible-light photoexcitation due to its suitable band gap of 2.7 eV . Despite its good stability even at high temperatures (up to 600 °C), the low conductivity, small specific surface area, and rapid charge-hole recombination limit its widespread use in many photocatalytic processes . Thus, several approaches have been employed to improve the photocatalytic activity of g-C 3 N 4 , such as doping with metal/nonmetal, creating defects, forming heterostructured composites, and morphological engineering .…”

Application of biowaste and nature-inspired (nano)materials in fuel cells

“…12 Due to the vast energy applications, there is a high demand for energy, and hence it is important to boost the preparation of cost-effective, abundant, and efficient materials. 13,14 In the last few decades, nature-inspired materials have been considerably used as renewable, nontoxic, and risk-free sources in research and industrial activities to synthesize inexpensive and environment-friendly nanocomposites and nanocatalytic systems. 15 Natural materials are a good option for the stabilization of NPs, and consequently the preparation of catalytic structure.…”