Bifunctional Perovskite‐BiVO₄ Tandem Devices for Uninterrupted Solar and Electrocatalytic Water Splitting Cycles

Abstract

Photoelectrochemical (PEC) fuel synthesis depends on the intermittent solar intensity of the diurnal cycle and ceases at night. Here, an integrated device that does not only possess PEC water splitting functionality, but also operates as an electrolyzer in the nocturnal period to improve the overall capacity factor is described. The bifunctional system is based on an “artificial leaf” tandem PEC architecture that contains an inverse‐structure lead halide perovskite protected by a graphite epoxy/parylene‐C coating (conferring 96 h stability of operation in water), and a porous BiVO4 semiconductor. The light‐absorbers are interfaced with a H2 evolution catalyst (Pt) and a Co‐based water oxidation catalyst, respectively, which can also be directly driven by electricity. Thus, the device can operate in PEC mode during irradiation and switch to an electricity‐powered mode in the dark through bypassing of the semiconductor configuration. The bifunctional perovskite‐BiVO4 tandem provides a solar‐to‐hydrogen efficiency of 1.3% under simulated solar irradiation and an onset for water electrolysis at 1.8 V. The compact design and low cost of the proposed device may provide an advantage over other technologies for round‐the‐clock fuel production.

Reforming of Soluble Biomass and Plastic Derived Waste Using a Bias‐Free Cu30Pd70|Perovskite|Pt Photoelectrochemical Device

“…The perovskite|Pt cathode was formed by sandwiching the hybrid organic‐inorganic halide perovskite between electron and hole transporting layers (Figure S13, Supporting Information shows the cross‐section FESEM of the cathode), and was then encapsulated before Pt deposition (see Experimental Section for details and Figure S14, Supporting Information, for optical images). [ 40 ] For the PEC measurements, the perovskite layer was back‐illuminated through FTO‐glass. The perovskite devices achieved an average open circuit voltage ( V oc ) of 1.08 ± 0.03 V (Figure S15, Supporting Information), and the perovskite|Pt photocathode irradiated with simulated solar light (AM 1.5G, 100 mW cm −2 ) showed an onset potential of ≈1.0 V versus RHE for H 2 evolution in a three‐electrode configuration (Figure S16a, Supporting Information).…”

“…Preparation of Inverse Structure Perovskite: The inverse structure triple cation mixed halide perovskite devices were prepared according to the previously reported method with minor modifications. [14,40] Briefly, a NiO x hole-transporting layer (HTL) was uniformly deposited on FTO-coated glass via spin-coating of 1 M Ni(NO 3 ) 2 •6H 2 O, 1 M ethylenediamine solution in ethylene glycol. The FTO-coated glass was then subjected to annealing treatment at 573 K. A second HTL was added over the NiO x layer by spin coating F4TCNQ-doped PTAA solution inside an N 2 -filled glove box.…”

“…Product Detection and Quantification: The amount of H 2 evolved from the perovskite|Pt cathode was detected and quantified by manual injection from the PEC cell headspace into a Shimadzu GC-2010 Plus gas chromatograph (GC) and quantified using methane as the internal standard. [40] The chromatographic separations for oxidation products were conducted with a Phenomenex Rezex 8% H+ column at 75 °C column temperature. Samples were analyzed in the isocratic flow mode (flow rate 0.0025 M H 2 SO 4 in water, 0.5 mL min −1 ) using a Waters breeze system equipped with refractive index (RID-2414) and diode array UVvis (λ = 202 nm) [51] detectors.…”

A Semi‐artificial Photoelectrochemical Tandem Leaf with a CO2‐to‐Formate Efficiency Approaching 1 %

“…Lead halide perovskite solar cells are notoriously moisture‐sensitive, but encapsulation strategies enable their application as photoelectrodes in aqueous solution [33–36] . Here, a previously reported triple cation lead mixed halide perovskite (Cs 0.07 (FA)(MA) 0.22 Pb 1.32 I 3.27 Br 0.66 ; formamidinium (FA); methylammonium (MA); see Figure S3 for photovoltaic performance), was sandwiched between hole/electron charge transfer layers and encapsulated by a graphite epoxy (GE) paste (PVK; Figure S4) [37] . The IO‐TiO 2 scaffold was combined with the PVK photoelectrode via a Ti foil, which provided structural support and enhanced the moisture protection of the photoabsorber [24] .…”

Developments and Perspectives on Robust Nano‐ and Microstructured Binder‐Free Electrodes for Bifunctional Water Electrolysis and Beyond

“…The wire notation corresponds to panel a. Reproduced with permission. [ 499 ] Copyright 2020, Wiley. ii‐a) J – V curves of solar‐assisted overall water splitting cells under AM 1.5 G 1 sun illumination of BVO (−) versus Ni foam (+) and MX@C/BVO (−) versus MX@C (on Ni foam, +).…”