Nickel incorporated graphitic carbon nitride supported copper sulfide for efficient noble-metal-free photo-electrochemical water splitting

Chaudhary, Preeti; Ingole, Pravin P.

doi:10.1016/j.electacta.2020.136798

Cited by 31 publications

(14 citation statements)

References 39 publications

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“…In Nyquist plots, the semicircle diameter is used as an indicator of the electron-transfer resistance on an electrode surface. Smaller and larger semicircles reflect lower and higher charge transfer resistances, which imply faster and slower charge transfer at the electrode/electrolyte interface, respectively. , The FeS 2 /TiO 2 electrode has a smaller semicircle than Ann.FeS 2 and NonAnn.FeS 2 electrodes, i.e., it can effectively enhance charge transfer from the electrode surface to the electrolyte. , The thin (∼72 nm) and porous TiO 2 layer may allow charge transfer from the electrode surface to the electrolyte. , Significantly, the TiO 2 thin layer inhibited the weathering process, which agrees with the previous results of the present study. Remarkably, the FeS 2 /TiO 2 electrode displayed enhanced conductivity with a lower charge transfer resistance and fast kinetics.…”

Section: Results and Discussionsupporting

confidence: 91%

“…Due to the annealing of TiO 2 , it became more crystalline and porous, as observed from the TiO 2 FESEM image (Figure S8). The crystalline grains enhance the electrical conductivity, which is a key characteristic of electrical transport from the electro-adsorbed materials to the catalyst. − It is well reported that the Ann.TiO 2 protective layer showed columnar crystallinity, conductivity, and stability and became electronically leaky during the OER process. , Different studies reported similar electronically leaky behavior during the electrochemical reaction with a range of coating thicknesses of the TiO 2 layer. ,, These results indicate that the TiO 2 overlayer could help to display better electrocatalytic durability toward the OER than that we actually noted for FeS 2 /TiO 2 samples studied in the present report. The i – t curve measurements were performed to assess the electrochemical stability of the FeS 2 /TiO 2 catalyst by holding the potential at 1.7 V. Figure e shows that the current density ranges from 2.8 to 6.7 mA/cm 2 in 14 h. The initial current density (2.8 mA/cm 2 ) is increased with time due to the activation process of the FeS 2 /TiO 2 electrode, which produces more active sites on the electrode surface, and then remains stable at 6.7 mA/cm 2 for over 14 h. Consequently, without any surface oxidation, FeS 2 /TiO 2 maintained OER stability (Figure e) for 14 h with a constant current density of 6.7 mA/cm 2 at 1.77 V vs RHE.…”

Section: Results and Discussionmentioning

confidence: 99%

“…50,52 The FeS 2 /TiO 2 electrode has a smaller semicircle than Ann.FeS 2 and NonAnn.FeS 2 electrodes, i.e., it can effectively enhance charge transfer from the electrode surface to the electrolyte. 45,52 The thin (∼72 nm) and porous TiO 2 layer may allow charge transfer from the electrode surface to the electrolyte. 44,45 Significantly, the TiO 2 thin layer inhibited the weathering process, which agrees with the previous results of the present study.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Physical Barricading at the Nanoscale: Protecting Pyrite from Weathering toward Efficient and Stable Electrocatalysis of the Oxygen Evolution Reaction

Pandey

Gahlawat

Ingole

2020

ACS Sustainable Chem. Eng.

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The unique atomic arrangement and excellent charge transfer properties of two-dimensional (2D) metal chalcogenides (MX 2 ; M = transition metal, X = S, Se) make them effective electrocatalysts toward water splitting. But, so far, none of them have been able to replace noble-metal catalysts for the oxygen evolution reaction (OER), and it remains a great challenge to develop these catalysts. Specifically, cost-effective and earth-abundant FeS 2 has shown potential, but it is less acknowledged due to the associated weathering process. Here, we report a spin-coated TiO 2 layer on hydrothermally synthesized 2D-FeS 2 nanoplates to control weathering through physical barricading at the nanoscale. Notably, the electrochemical and chemical weathering studies suggest that the TiO 2 layer stabilized FeS 2 oxidation in alkaline solution, while the latter gets oxidized without TiO 2 overlayers. To the best of our knowledge, this would be the first report on an FeS 2 /TiO 2 photoanode for efficient and stable OER without any composite or doping. It displayed improved long-term durability of OER activity. Moreover, the annealed crystalline leaky TiO 2 layer (∼72 nm) remarkably displayed enhanced charge transfer at the FeS 2 /TiO 2 interface. Also, Mott−Schottky measurements confirmed that the leaky TiO 2 served as a protective layer (physical barrier) against the weathering of FeS 2 . The current study may provide new insights into the rational design of low-cost FeS 2 /TiO 2 layered electrocatalysts for OER and renewable energy applications.

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Section: Results and Discussionsupporting

confidence: 91%

Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Physical Barricading at the Nanoscale: Protecting Pyrite from Weathering toward Efficient and Stable Electrocatalysis of the Oxygen Evolution Reaction

Pandey

Gahlawat

Ingole

2020

ACS Sustainable Chem. Eng.

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“…[11,[54][55] Co doping induced a decrease in the band gap, consequently lowering the charge transfer resistance and facilitating the dynamic kinetics, resulting in excellent HER activity. [56][57] In contrast, Fe doping increased the band gap, inevitably increasing the charge transfer resistance and decreasing the HER activity. The results showed that the band gap variation was in agreement with the results of the activity and EIS measurements, suggesting that the band gap was an essential factor in modifying the HER performance in this study.…”

Section: Resultsmentioning

confidence: 99%

Tuning the Electronic Structure of Tungsten Oxide for Enhanced Hydrogen Evolution Reaction in Alkaline Electrolyte

Zhang

et al. 2022

ChemElectroChem

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Engineering the electronic structure of HER catalysts has been suggested to improve the performance of noble metal‐free catalysts in alkaline electrolytes. Herein, we demonstrated that a suitable cation doping in the tungsten oxide catalyst modified the interfacial structure, surface chemical state and band gap value, which enhanced the HER performance. For the experiments, the cation (Ni, Co and Fe) doped tungsten oxide catalysts were synthesized on nickel foam, on which Ni‐based alloy was decorated. The Co doped catalyst (Co−WO) exhibited an extraordinary HER activity, with a low overpotential of 30 mV at a current density of 10 mA cm−2, Tafel slope of 32 mV dec−1. In this system, the Ni‐based alloy–tungsten oxide interface facilitated water dissociation. Moreover, the decreased band gap and improved conductivity induced by Co doping, further enhanced the charge transfer ability in the HER process. The regulated metal‐oxide heterostructure coupled with cation doping endowed the catalyst with efficient interface active sites, superior electrical conductivity, and enhanced electron transfer kinetics, facilitating the HER performance.

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“…In this field, the research on photoelectrochemical (PEC) water splitting (WS) relies on semiconductor electrodes (generally metal oxides) that exhibit appreciable photogenerated charge separation at the solid/liquid interface when illuminated by sunlight [6][7][8][9]. To the best of our knowledge, studies on photoelectrochemical cells were conducted, even recently [10][11][12][13][14], in a liquid electrolyte, thus requiring post-processing energy to separate evolved gas from water splitting. In our recent work, tandem photoelectrochemical cells were constituted by a solid polymeric membrane, acting as both gas separator and electrolyte, sandwiched between a photoanode and a photocathode [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Water Splitting with Enhanced Efficiency Using a Nickel-Based Co-Catalyst at a Cupric Oxide Photocathode

et al. 2021

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Homemade non-critical raw materials such as Ni or NiCu co-catalysts were added at the photocathode of a tandem cell, constituted by photoelectrodes made of earth-abundant materials, to generate green solar hydrogen from photoelectrochemical water splitting. Oxygen evolving at the Ti-and-P-doped hematite/TCO-based photoanode and hydrogen at the cupric oxide/GDL-based photocathode are separated by an anion exchange polymer electrolyte membrane placed between them. The effect of the aforementioned co-catalysts was studied in a complete PEC cell in the presence of the ionomer dispersion and the anionic membrane to evaluate their impact under practical conditions. Notably, different amounts of Ni or NiCu co-catalysts were used to improve the hydrogen evolution reaction (HER) kinetics and the overall solar-to-hydrogen (STH) efficiency of the photoelectrochemical cells. At −0.6 V, in the bias-assisted region, the photocurrent density reaches about 2 mA cm−2 for a cell with 12 µg cm−2 of Ni loading, followed by 1.75 mA cm−2 for the cell configuration based on 8 µg cm−2 of NiCu. For the best-performing cell, enthalpy efficiency at −0.4 V reaches a first maximum value of 2.03%. In contrast, the throughput efficiency, which is a ratio between the power output and the total power input (solar + electric) provided by an external source, calculated at −1.225 V, reaches a maximum of 10.75%. This value is approximately three times higher than the best results obtained in our previous studies without the use of co-catalysts at the photocathode.

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Nickel incorporated graphitic carbon nitride supported copper sulfide for efficient noble-metal-free photo-electrochemical water splitting

Cited by 31 publications

References 39 publications

Physical Barricading at the Nanoscale: Protecting Pyrite from Weathering toward Efficient and Stable Electrocatalysis of the Oxygen Evolution Reaction

Physical Barricading at the Nanoscale: Protecting Pyrite from Weathering toward Efficient and Stable Electrocatalysis of the Oxygen Evolution Reaction

Tuning the Electronic Structure of Tungsten Oxide for Enhanced Hydrogen Evolution Reaction in Alkaline Electrolyte

Water Splitting with Enhanced Efficiency Using a Nickel-Based Co-Catalyst at a Cupric Oxide Photocathode

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