Abstract
Dual direct Z-scheme photocatalysts for overall water decomposition have demonstrated strong redox abilities and the efficient separation of photogenerated electron–hole pairs. Overall water splitting utilizing NiAl-LDH-based binary and ternary nanocomposites has been extensively investigated. The synthesized binary and ternary nanocomposites were characterized via XRD, FTIR, SEM, HRTEM, XPS, UV-DRS, and photoelectrochemical measurements. The surface wettability properties of the prepared nanocomposites were measured via contact angle measurements. The application of the NiAl-LDH/g-C3N4/Ag3PO4 ternary nanocomposite was investigated for photocatalytic overall water splitting under light irradiation. In this work, we found that in the presence of Ag3PO4, the evolution of H2 and O2 is high over LCN30, and 2.8- fold (O2) and 1.4-fold (H2) activity increases can be obtained compared with the use of LCN30 alone. It is proposed that Ag3PO4 is involved in the O2 evolution reaction during water oxidation and g-C3N4 is involved in overall water splitting. Our work not only reports overall water splitting using NiAl-LDH-based nanocomposites but it also provides experimental evidence for understanding the possible reaction process and the mechanism of photocatalytic water splitting. Photoelectrochemical measurements confirmed the better H2 and O2 evolution abilities of NiAl-LDH/g-C3N4/Ag3PO4 in comparison with NiAl LDH, g-C3N4, Ag3PO4, and LCN30. The observed improvement in the gas evolution properties of NiAl LDH in the presence of Ag3PO4 is due to the formation of a dual direct Z-scheme, which allows for the easier and faster separation of charge carriers. More importantly, the LCNAP5 heterostructure shows high levels of H2 and O2 evolution, which are significantly enhanced compared with LCN30 and pure NiAl LDH.
Highlights
The photocatalytic production of hydrogen and oxygen is one of the most promising approaches for overcoming both the energy and environmental issues that currently exist worldwide
The peak at 806 cmÀ1 is related to the stretching mode of the s-triazine unit of g-C3N4.40,41 In the case of pure Ag3PO4, the peaks observed at 1030 and 550 cmÀ1 can be ascribed to the P–O stretching vibration of PO4.42 As can be seen, all the characteristic peaks of NiAl-layered doubled hydroxides (LDHs), Ag3PO4, and g-C3N4 are observed in the LCNAP samples, con rming the formation of
The results obtained from the PL measurements of LCNAP5 support the photocurrent measurement results, which indicated that electron–hole-pair separation was improved upon introducing Ag3PO4 on LCN30, which further leads to efficient photocatalytic evolution
Summary
2D layered materials have attracted extensive attention for photocatalytic water splitting. As a representative of layered materials, layered doubled hydroxides (LDHs) have attracted much attention in the eld of catalysis due to their structures They have large surface-to-volume ratios, excellent chemical stability, low cost, low toxicity,. If suitable water redox composites are formed with LDHs, gaseous hydrogen and oxygen evolution could be achieved through water splitting.[18] Polymeric g-C3N4 has recently attracted attention due to its enhanced visible response, tunable band structure, and extraordinary thermal and chemical stability.[19,20] Formerly, our group studied the photocatalytic H2 evolution rates of LDH/g-C3N4 (in the presence of TEOA) composites through water splitting, which exhibited remarkable activities.[11] the excellent photocatalytic performance of LCN30 could be further improved through increasing the lifetimes of electrons and holes. The enhanced activity of the dual direct Z-scheme photocatalyst can be attributed to Ag3PO4
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
