Construction of inorganic–organic 2D/2D WO₃/g-C₃N₄ nanosheet arrays toward efficient photoelectrochemical splitting of natural seawater

Abstract

Hydrogen production from seawater and solar energy based on photoelectrochemical cells is extremely attractive due to earth-abundance of seawater and solar radiation. Herein, we report the successful fabrication of novel inorganic-organic 2D/2D WO3/g-C3N4 nanosheet arrays (WO3/g-C3N4 NSAs) grown on a FTO substrate via a facile hydrothermal growth and deposition-annealing process, and their application in natural seawater splitting. The results indicate that the WO3/g-C3N4 NSAs exhibit a photocurrent density of 0.73 mA cm(-2) at 1.23 V versus RHE under AM 1.5G (100 mW cm(-2)) illumination, which is 2-fold higher than that of WO3 NSAs. More importantly, the WO3/g-C3N4 NSA photoanode is quite stable during seawater splitting and the photocurrent density does not substantially decrease after continuous illumination for 3600 s. The remarkably enhanced performance originates primarily from the formation of the WO3/g-C3N4 heterojunction between WO3 and g-C3N4 nanosheets, which accelerates charge transfer and separation, and prolongs the lifetime of electrons as demonstrated by EIS and Mott-Schottky analyses. Finally, a possible mechanism for the improved performance was proposed and discussed.

Tailoring a Zinc Oxide Nanorod Surface by Adding an Earth‐Abundant Cocatalyst for Induced Sunlight Water Oxidation

“…For instance, it was verified that a small fraction of Cl − remained in solution and it was suggested that the chlorine oxidation reaction may be an intermediate process for seawater splitting . These reports used an artificial solution and a filtrated natural seawater where the pH was 6.5, the same used in this work . At this condition, it is known that there is the highest chlorine oxidation reaction.…”

“…[34] These reports used an artificial solution and a filtrated natural seawater where the pH was 6.5, the same used in this work. [34][35][36] At this condition, it is known that there is the highest chlorine oxidation reaction. Hence, this may be the reason why the photocurrent density has a lower value in comparison to the experiment using Na 2 SO 4 as electrolyte -the major contribution in this case is the chlorine reaction, but still there is oxygen evolution.…”

Preparation of WO3/CNT catalysts in presence of ionic liquid [C16mim]Cl and catalytic efficiency in oxidative desulfurization

“…The peak for C 1s is located at 284.53 eV, which is a CC in which carbon atoms exist in the form of sp 2 hybridization, reflecting the graphitized structure of CNT . The peaks for W 4f at 35.7 and 37.9 eV correspond to W 4f 7/2 and W 4f 5/2 of W 6+ oxidation state respectively . The major peak for O 1s located at 530.8 eV contributes to WO, and O of WO 3 exists in the form of O 2− , while the broad peak at 532.4 eV corresponds to OH groups of adsorbed water molecules …”

Synthesis of g‐C3N4/ZnGa1.9Al0.1O4 Heterojunction Using Narrow and Wide Band Gap Material for Enhanced Photoelectrochemical Water Splitting

“…Solar energy is renewable in nature and no harmful by‐product(s) is produced. Photoelectrochemical (PEC) water splitting is one of the most promising, economically viable and sustainable way of clean solar fuel production in the form of hydrogen . Despite the recent advancement in PEC, many challenges still remain in improving energy conversion efficiency, such as utilizing wider range of photons for hydrogen production, enhancing the reaction kinetics and increasing the stability and lifetime of semiconductor materials …”