Engineering g-C3N4 with CuAl-layered double hydroxide in 2D/2D heterostructures for visible-light water splitting.

[Display omitted] • CuAl-LDH/g-C 3 N 4 heterostructures were successfully fabricated via non-covalent co-assembling. • CuAl-LDH/g-C 3 N 4 own higher separation and transportation of charge carrier at interface. • The introduction of CuAl-LDH extends the photoresponse to long wavelength region. • CuAl-LDH/g-C 3 N 4 exhibited outstanding visible-light photoactivity towards H 2 and O 2 generation. • CB and VB positions of CuAl-LDH/g-C 3 N 4 heterojunction suggest a S-scheme mechanism. CuAl layered double hydroxide (LDH) and polymeric carbon nitride (g-C 3 N 4 , GCNN) were assembled to construct a set of novel 2D/2D CuAl-LDH/GCNN heterostructures. These materials were tested towards H 2 and O 2 generation from water splitting using visible-light irradiation. Compared to pristine materials, the heterostructures displayed strongly enhanced visible-light H 2 evolution, dependent on the LDH content, which acts as a cocatalyst, replacing the benchmark Pt. The optimal LDH loading was achieved for 0.2CuAl-LDH/GCNN that exhibited an increased number of active sites and showed a trade-off between charge separation efficiency and light shading, resulting in a 32-fold increase in the amount of evolved H 2 compared with GCNN. In addition, the 0.2CuAl-LDH/GCNN heterostructure generated 1.5 times more O 2 than GCNN. The higher photocatalytic performance was due to efficient charge carriers' separation at the heterojunction interface via an S-scheme (corroborated by work function, steady-state and time-resolved photoluminescence studies), enhanced utilisation of longer-wavelength photons (>460 nm) and higher surface area available for the catalytic reactions. [ABSTRACT FROM AUTHOR]