The growing demand for sustainable energy has intensified interest in photoelectrochemical (PEC) water splitting for green hydrogen production. Titanium dioxide (TiO 2 ), though stable and cost-effective, suffers from a wide bandgap (∼3.2 eV) and rapid charge recombination. Here, a TiO 2 –carbon–Pt/graphene composite photoelectrode was developed to overcome these limitations and achieve efficient solar-driven hydrogen generation. Anatase TiO 2 nanoparticles and carbon nanoparticles (CNPs) were synthesized via sol–gel and pyrolytic methods, decorated with photodeposited platinum (Pt) nanoparticles, and integrated onto a graphene substrate. Structural and optical analyses confirmed successful component integration. CNPs enhanced visible-light absorption and induced photothermal effects, enhancing visible-light absorption through carbon-induced sub-bandgap states. Pt (2–5 nm) provided catalytic hydrogen evolution sites, while graphene enabled rapid charge transport. Under AM 1.5 G illumination (100 mW/cm 2 ) in 0.27 M KOH, the composite delivered an effective steady-state photocurrent density of ∼3.5 mA cm −2 at 0.5 V vs reversible hydrogen electrode during continuous PEC operation. The electrode achieved an applied bias photon-to-electron efficiency of 4.3%, with comparable performance under direct sunlight. It retained ∼82% of its initial photocurrent after 100 h continuous operation, confirming long-term durability. Scalable electrodes (10 cm²) exhibited near-linear scaling of steady-state photocurrent, confirming reproducibility while accounting for expected series-resistance effects at larger areas. Enhanced performance arose from synergistic effects: CNPs broadened absorption and accelerated kinetics, Pt catalyzed the hydrogen evolution reaction, and graphene facilitated efficient electron transport. Overall, this work highlights the effectiveness of synergistically integrating light-absorbing CNPs, catalytic platinum, and conductive graphene to overcome the intrinsic limitations of TiO 2 photoelectrodes.
Dey et al. (Wed,) studied this question.