Promoting the Photoelectrochemical Properties of BiVO₄ Photoanode via Dual Modification with CdS Nanoparticles and NiFe-LDH Nanosheets

Bismuth vanadate (BiVO₄) has long been considered a promising photoanode material for photoelectrochemical (PEC) water splitting. Despite its potential, significant challenges such as slow surface water evolution reaction (OER) kinetics, poor carrier mobility, and rapid charge recombination limit its application. To address these issues, a triadic photoanode has been fabricated by sequentially depositing CdS nanoparticles and NiFe-layered double hydroxide (NiFe-LDH) nanosheets onto BiVO₄, creating a NiFe-LDH/CdS/BiVO₄ composite. This newly engineered photoanode demonstrates a photocurrent density of 3.1 mA cm⁻² at 1.23 V vs. RHE in 0.1 M KOH under AM 1.5 G illumination, outperforming the singular BiVO₄ photoanode by a factor of 5.8 and the binary CdS/BiVO₄ and NiFe-LDH/BiVO₄ photoanodes by factors of 4.9 and 4.3, respectively. Furthermore, it exhibits significantly higher applied bias photon-to-current efficiency (ABPE) and incident photon-to-current efficiency (ICPE) compared to pristine BiVO₄ and its binary counterparts. This enhancement in PEC performance is ascribed to the formation of a CdS/BiVO₄ heterojunction and the presence of a NiFe-LDH OER co-catalyst, which synergistically facilitate charge separation and transfer efficiencies. The findings suggest that dual modification of BiVO₄ with CdS and NiFe-LDH is a promising approach to enhance the efficiency of photoanodes for PEC water splitting.