EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Driven by the decreasing fossil fuel consumption, increasing energy demand, and environmental pollution, the search for clean and sustainable energy is attracting tremendous research interest. Photocatalytic water splitting to produce hydrogen (H2) using a semiconductor material is considered one of the most promising technologies to take advantage of solar energy conversion [1,2]. However, the core challenge of this process lies in the low efficiency offered by single semiconductors, which often suffer from the fast recombination of electron-hole pairs. The construction of two-dimensional (2D) heterostructures nanomaterials has proven to be an effective strategy for enhancing photocatalytic performance. These 2D/2D nanohybrids can offer a short migration distance and boost the separation of photoinduced carriers, thus improving light conversion efficiency. In this context, the present work aims to fabricate and optimise the design of 2D/2D materials by coupling different loads of a CuAl layered double hydroxide (CuAl-LDH) material with graphitic carbon nitride nanosheets (GCNN) by electrostatic co-assembly. The photocatalytic results revealed that all the nanohybrids exhibited higher visible-light-driven photocatalytic H2 and O2 evolution than the bare GCN and CuAl-LDH. Several characterisation methods depicted the physical chemistry and morphology nature of the photocatalysts. The enhanced performance efficiency was ascribed to efficient electron-hole separation at the intimate heterojunction interface (according to steady-state and time-resolved photoluminescence), improved visible light absorption and narrower bandgap (shown by diffuse reflectance spectroscopy) and increased number of active sites (higher specific surface area). These results will hopefully offer new insights on the construction of innovative LDH-GCN nanomaterials for photocatalytic applications.

[1] E.S. Da Silva, N.M.M. Moura, M.G.P.M.S. Neves, A. Coutinho, M. Prieto, C.G. Silva, J.L. Faria, Appl. Catal. B-Environ., 221, 2018, 56-69.
[2] E.S. Da Silva, N.M.M. Moura, A. Coutinho, G. Dražić, B.M.S. Teixeira, N.A. Sobolev, C.G. Silva, M.G.P.M. S. Neves, M. Prieto, J.L. Faria, ChemSusChem, 11, 2018, 2681-2694