Dual-functional PANI/MIL-125(Ti) photoanodes for enhanced photoelectrochemical H2 generation and photothermal heating

MIL-125(Ti) metal-organic framework coated with HCl doped conducting polyaniline (PANI) photocatalyst (PANI/MIL-125(Ti)) was fabricated for photoelectrochemical (PEC) hydrogen production under visible LED illumination. PANI coating not only decreased the band gap of MIL-125(Ti), but also increased electron mobility of the overall structure due to its π-conjugated structure that provided a remarkable increase in current density, reaching to 6.55 mA/cm 2 (at 1.23 V vs. RHE) under visible LED irradiation. Furthermore, the applied bias photon-to-current efficiency (ABPE) revealed that the highest ABPE value (2.36%) was found for PANI/MIL-125(Ti) photoanodes (under LED illumination at 1.01 V vs RHE). These superior PEC H 2 evolution performance strongly imply the role of PANI as a hole-transporter upon visible LED irradiation for efficient charge separation and reduced electron hole recombination with prolonged life time using PANI/MIL-125(Ti) photoanodes. Besides, the noteworthy photothermal power conversion efficiency (PCE = 79.3%) provides a unique platform to enhance the energy-conversion in the fields of photocatalysis, energy storage, and photothermal applications. • Novel PANI/MIL-125(Ti) nanostructures were fabricated for PEC hydrogen production. • PANI coating improved the light absorption in visible spectrum (450–525 nm). • PANI/MIL-125(Ti) showed higher PEC performance (6.55 mA/cm 2 at 1.23 V vs. RHE). • PANI utilized as hole-transporter upon LED irradiation for superior H 2 evolution. • Photoanodes showed good photothermal power conversion efficiency (PCE = 79.3%).