Advanced Nanostructured Conjugated Microporous Polymer Application in a Tandem Photoelectrochemical Cell for Hydrogen Evolution Reaction

Abstract

Solar energy conversion through photoelectrochemical cells by organic semiconductors is a hot topic that continues to grow due to the promising optoelectronic properties of this class of materials. In this sense, conjugated polymers have raised the interest of researchers due to their interesting light‐harvesting properties. Besides, their extended π‐conjugation provides them with an excellent charge conduction along the whole structure. In particular, conjugated porous polymers (CPPs) exhibit an inherent porosity and three‐dimensional structure, offering greater surface area, and higher photochemical and mechanical stability than their linear relatives (conjugated polymers, CPs). However, CPP synthesis generally provides large particle powders unsuitable for thin film preparation, limiting its application in optoelectronic devices. Here, a synthetic strategy is presented to prepare nanostructures of a CPP suitable to be used as photoelectrode in a photoelectrochemical (PEC) cell. In this way, electronic and photoelectrochemical properties are measured and, attending to the optoelectronic properties, two hybrid photoelectrodes (photoanode and photocathode) are designed and built to assemble a tandem PEC cell. The final device exhibits photocurrents of 0.5 mA cm−2 at a 0.7 V in the two electrode configuration and the hydrogen evolution reaction is observed and quantified by gas chromatography, achieving 581 µmol of H2 in a one‐hour reaction.

Light-Driven Nitrogen Fixation to Ammonia over Aqueous-Dispersed Mo-Doped TiO2 Colloidal Nanocrystals

“…On the one hand, the R s (Figure b) shows a flat behavior with the applied potential for both samples, showing values between 25 and 60 Ω cm 2 range. On the other hand, the charge-transfer resistances of both samples (Figure c) decrease under illumination, as expected for a photoelectrode. − Additionally, under dark and illumination conditions, the Mo-doped sample shows lower values of R ct along the whole potential window, in good agreement with its higher photocurrent. Furthermore, both samples show a clear decrease in the capacitance with the applied potential (Figure d), as a consequence of an enhanced extraction of the photogenerated holes from the semiconducting absorber to the electrolyte, as expected for an n-type semiconductor. , Mo-doped TiO 2 shows higher capacitance values along the whole potential window, which can be related to a higher density of photogenerated holes.…”

Solar-Driven Hydrogen Production Using a BODIPY Covalent Organic Framework Hybrid Photocatalyst

“…Photovoltage measurements confirm the photoactive properties of IEC-1, exhibiting the characteristic behavior of a p-type semiconductor and showing an increase in the signal under illumination (Figure S16A). 47 The photoresponse of the electrode when illuminating in open circuit potential is 130 mV. Besides, the linear sweep voltammetry measurements under chopped illumination (Figure S16B) confirm the photoactivity of this material and its potential to be used as a photocathode due to the presence of negative photocurrents along the whole potential window.…”

Disentangling the Role of Ag‐Based Nanocorals as Efficient Cocatalyst over CuBi2O4 Photocathodes Toward Hydrogen Evolution Reaction

“…Under illumination, the CuBi 2 O 4 samples show an increase in the OCP values, associated with the positive splitting of the pseudo‐Fermi levels, characteristic of a p‐type semiconductor, confirming the photoactive and semiconducting nature of this material and its possible use as a photocathode. [ 29 ] Specifically, the samples presented herein show a photovoltage of 0.350.05 V. Figure 3B shows the J–V under front (blue trace) and back (brown trace) chopped illumination at the CuBi 2 O 4 photocathode. As shown in this figure, the sample shows around twice photocurrent densities under back illumination, due to a slow hole transport in the film.…”