A Single-Junction Cathodic Approach for Stable Unassisted Solar Water Splitting

Wang, Yongjie; Wu, Yuanpeng; Schwartz, Jonathan; Sung, Suk Hyun; Hovden, Robert; Mi, Zetian

doi:10.1016/j.joule.2019.07.022

Cited by 42 publications

(31 citation statements)

References 69 publications

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“…The tabulated data from this figure can be found in Tables 1 and 2. 2,16,[52][53][54][55][56][57][58][59][60][61]21,[62][63][64][65][66][67][68][69][70][71][45][46][47][48][49][50][51] These solar-driven water splitting devices have several device architectures: 1) A monolithic device integrating semiconductor(s), an HER catalyst, and an OER catalyst without wires. 2) One photoelectrode integrating semiconductor(s) and either an HER catalyst or an OER catalyst, which is wired to a counter electrode.…”

Section: Figurementioning

confidence: 99%

Addressing the Stability Gap in Photoelectrochemistry: Molybdenum Disulfide Protective Catalysts for Tandem III–V Unassisted Solar Water Splitting

et al. 2020

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While photoelectrochemical (PEC) solar-to-hydrogen efficiencies have greatly improved over the past few decades, advances in PEC durability have lagged behind. Corrosion of semiconductor photoabsorbers in the aqueous conditions needed for water splitting is a major challenge that limits device stability. In addition, a precious-metal catalyst is often required to efficiently promote water splitting. Herein, we demonstrate unassisted water splitting using a non-precious metal molybdenum disulfide nanomaterial catalytic protection layer paired with a GaInAsP/GaAs tandem device. This device was able to achieve stable unassisted water splitting for nearly 12 hours, while a sibling sample with a PtRu catalyst was only stable for 2 hours, highlighting the advantage of the non-precious metal catalyst. In situ optical imaging illustrates the progression of macroscopic degradation that causes device failure. In addition, this work compares unassisted water splitting devices across the field in terms of the efficiency and stability, illustrating the need for improved stability. TOC GRAPHICThe primary strategy that has emerged to mitigate semiconductor surface corrosion is depositing thin films, such as titanium dioxide, that can act as protective barriers to prevent the electrolyte from coming into contact with the semiconductor surface. 7,8 These films have to be stable, thin enough to prevent significant light blocking, conformal, and conductive to create a stable and functional device. 9-11 Furthermore, if these films do not demonstrate intrinsic catalytic activity, an additional hydrogen and/or oxygen evolution catalyst is needed to promote efficient water splitting. Molybdenum disulfide nanomaterials have been shown to stabilize a variety of singlejunction Si and III-V PEC systems, functioning as a hydrogen evolution reaction (HER) catalyst and protection layer. [9][10][11][12][13][14][15] Because of the promising performance in single-junction photocathodes, it is of interest to use MoS2 with tandem semiconductor systems to improve the stability during unassisted solar water splitting.While most III-V-based unassisted water splitting devices to date have incorporated a Ga0.51In0.49P (hereafter GaInP2) (1.8 eV) top cell, device lifetimes have been limited to <100 h. 7,16 GaxIn1-xAsyP1-y (1.7 eV) has shown promise as a PV material and has been paired with a GazIn1-zAs bottom cell (1.1 eV) for efficient tandem PV systems, motivating efforts to incorporate GaxIn1-xAsyP1-y into PEC systems and investigate the stability of this quaternary top cell. [16][17][18][19] The composition of GaxIn1-xAsyP1-y (hereafter GaInAsP), nominally x ~ 0.68 and y ~ 0.34, gives the desired bandgap of 1.7 eV and a lattice constant matching that of GaAs. 16,18 A GaInAsP/GaAs (1.7/1.4 eV) pairing has a predicted maximum STH efficiency of ~12%, 16,19 far from the ideal combination of absorbers to achieve the highest of efficiencies, however sufficiently high to perform durability studies on active, unassisted water splitting systems, guiding t...

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Section: Figurementioning

confidence: 99%

Addressing the Stability Gap in Photoelectrochemistry: Molybdenum Disulfide Protective Catalysts for Tandem III–V Unassisted Solar Water Splitting

et al. 2020

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“…Noble metals (e.g., Pt, Rh, Ag, and Au NPs) and noble metal oxides (e.g., IrO 2 and RuO 2 ) were found to be effective co‐catalysts for the HER/CRRs and OER, respectively. [ 18,20,21,42,43 ] However, the high cost of the noble materials restricts the scaling up of the production of noble‐metal‐based PEC devices and encourages the development of low‐cost, transition‐metal‐based surface modifications. As far as CRR is considered, the product selectivity mainly depends on the co‐catalysts.…”

Section: Design Of Electrode Materials For the Pec Cellmentioning

confidence: 99%

“…[ 49 ] The two‐electrode PEC cell consisting of mixed CuFeO 2 /CuO photocathode and Pt anode couples produced formate with an Eff STFm of 1% and >90% selectivity over 1 week without any external bias (Figure 3b and Table 1 ). Mi and co‐workers reported a single‐junction approach of p‐type In 0.25 Ga 0.75 N NWs for the first time (Figure 3c), [ 42 ] which exhibited an Eff STH of about 3.4% without an external bias with a photocurrent density of 2.8 mA cm −2 . Herein, the addition of an InGaN tunnel junction suppressed the recombination of the photogenerated charge carriers at the interface.…”

Section: Design and Development Of Stand‐alone Pec Cellsmentioning

confidence: 99%

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Stand‐Alone Photoelectrochemical Energy Conversions

et al. 2021

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The photoelectrochemical (PEC) conversions of water and atmospheric CO2 to value‐added fuels, such as H2, CH4, and CH3OH, can provide potential alternative sources for clean and environment‐friendly solar fuels. Several efforts are reported on the designing and developing stand‐alone PEC cells that efficiently produce H2 and O2 from water and minimize atmospheric CO2 via conversion to fuels under only sunlight. However, in reality, high overpotential, poor product‐selectivity, competitive side‐reactions, and self‐reduction of a catalyst limit the performance of the PEC cells, thereby requiring high power inputs. The choice of electrode materials and architectures of PEC cells are very important for designing stand‐alone and durable PEC cells with high solar‐to‐fuels conversion efficiency (EffSTF) and high selectivity. The present review provides a complete account of recent published works on stand‐alone PEC systems with different architectures; development of electrode materials for high EffSTF, selectivity, and stability; and the current challenges. Furthermore, this review describes the future outlook on stand‐alone PEC systems for future production of clean solar fuels and mitigation of atmospheric CO2 levels by utilizing only solar energy.

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“…reported a single‐junction approach of monolithically integrated InGaN NWs photocathode on n‐type Si wafers through an InGaN tunnel junction. [ 135 ] This single‐junction photocathode shows an STH efficiency of 3.4% at 0 V versus Pt and excellent stability for ≈300 h without using any extra passivation layers for unassisted solar water splitting.…”

Section: Recent Advances Of Surface/interface Structure Modulation Onmentioning

confidence: 99%

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

Lin

Wang

2020

Adv Funct Materials

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Photoelectrochemical (PEC) water splitting provides a promising approach to convert solar energy into hydrogen. Developing active, stable, and cost-effective semiconductors photoelectrodes is of great significance for achieving high-efficiency and large-scale hydrogen production. InGaN nanowires as an important candidate have gained a great upsurge in solar water splitting due to its tunable gap, high electron mobility, large active area, and excellent chemical stability. To obtain state-of-the-art InGaN nanowires-based photoelectrodes, tremendous efforts have been devoted to enhance light absorption capacity, charge carrier dynamics, and redox activity. In this review, recent advances in InGaN nanowires as photoelectrodes for PEC water splitting are comprehensively presented, with a focus on photoelectrode optimization strategies from the aspects of surface and interface structure modulation including doping engineering, energy band engineering, heterostructure engineering, and micro-nano engineering. The representative applications of InGaN nanowires-based PEC tandem cell are also discussed. Finally, perspectives on remaining challenges and future development are outlined.

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A Single-Junction Cathodic Approach for Stable Unassisted Solar Water Splitting

Cited by 42 publications

References 69 publications

Addressing the Stability Gap in Photoelectrochemistry: Molybdenum Disulfide Protective Catalysts for Tandem III–V Unassisted Solar Water Splitting

Addressing the Stability Gap in Photoelectrochemistry: Molybdenum Disulfide Protective Catalysts for Tandem III–V Unassisted Solar Water Splitting

Stand‐Alone Photoelectrochemical Energy Conversions

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

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